An Applied Approach to Viking-Era Brewing

If you’ve been following along – and of course you’ve been – you’ll have realized by now that I can get sidetracked by the details. Fall down rabbit holes. Go off on lengthy tangents that few people truly care about. Belabor the point. Beat a dead horse. Drive a joke into the ground so far that it comes out the other side at near escape velocity, sinks into a low orbit, passes funny 7 more times, and eventually makes landfall in an unassuming country bumpkin’s backyard in a fiery cataclysm that obliterates any semblance of joy or amusement said joke may have once imparted – and removes all other sorts of enjoyment with it.

I apologize for nothing. As is tradition.

However, I’ve realized more and more that I might want to make my brewing research somewhat more…approachable. My initial foray into simplification has been fairly successful – though it does take some commitment to peruse a poster and a number of references – but it’s always worthwhile to try new approaches.

In other words, I need to make this doable without digging kilns and drying malt with horse shit.

“But Pete! I love hard labor and the pungent smell of mostly-dried equine excrement!”

I know, I know, gentle readers – who doesn’t love picking over dead languages in pursuit of a pint? But information that cannot be digested by its audience is of little value – the bran muffin of the intellectual world. Boring, tasteless, and probably good for you – but seriously, blueberry is so much better and really the bran is just there to remind you of the better things in life, right?

Right, right, tangents. Back to business. Here, I will present a summary of the Viking-era brewing process I’ve cobbled together in some more specific detail; following that, I will present several ways that you can implement the principles without drifting too far from your comfort zone.

I am, after all, very concerned with your comfort.

I really just wanted to post this .gif again. Let's say it's something about experiments in human psychology. Yeah, that sounds right.


The Viking Method Summarized

1.) The Grains

Archaeological evidence suggests that the dominant cereals among the Norse included barley, oats, rye, and wheat in some locations. “Bread” finds from a number of Viking-age sites show that grains were often combined together. In addition, legumes and vetches were sometimes seen in conjunction with cereals.

Barley is the dominant grain type by far, and has been found as far north as Iceland and Greenland, indicating widespread intentional cultivation of the crop. 6-row barley seems to be found exclusively; a cultivar named “Bere” is believed to be descended from Viking-era barley crops.

Grains were probably sown in the spring and harvested not too long after – many landrace 6-row barleys can reach full maturation in 90 – 100 days. Grain would likely have been processed for storage soon after harvesting.

2.) The Processing

Malting was likely rooted in a form of grain processing that was originally intended to de-husk the grains. Grains would be soaked in water and then dried, allowing the husk to be removed easily. Such a method is also reflected in a fragmentary writing attributed to Zosimos of Panopolis, where a method of de-husking grain involves a few days of soaking in water.

The Senchas Mar, an 8th century Irish legal text, includes a detailed method for the malting of grain. This technique may have been passed along routes of cultural transmission to the Scots, who had contact with the Vikings – indeed, there were many Norse settlements in northern Scotland. A book on Norwegian farmhouse brewing traditions includes information about malting techniques purportedly derived from Viking tradition. In both cases, the processing is essentially the same: grains are steeped, heaped, allowed to sprout, and dried by a fire. The process takes 9 – 12 days depending on your specific method.

Corn-drying kilns in Scotland have been discovered. Fuels include local hardwoods, grasses, dung, and peat. Grains were probably soaked and dried en masse not too long after harvesting, to assist in processing.

Quern finds from Jorvik demonstrate the ability to generate flour. The technique in the Senchas Mar discusses turning the malt into “cakes;” it is plausible that the Viking-era “breads” which are found in the archaeological record are the result of this malting process. The flour would be mixed with water – possibly seawater – and formed into small unleavened biscuits which were dried over a fire.

As noted above, some of the Viking-era “breads” contained oil seeds and herbs. It is unclear when those may have been added, but addition either to the malting or to the grinding of the dried grain both seem plausible. It is unlikely that all grain was fortified, as most bread finds do not include flax or herbs.

3.) The Mashing

The “breads” that would result from processing acted as a method of easily preserving the grains for later use; these would form the “malt” for brewing. There is virtually no evidence pointing to a concrete mashing method employed by the Norse. However, disparate evidence may indicate a method.

Merryn Dineley suggests that structures identified as bath houses may have been brewhouses, and that fire-cracked rocks would have been used to heat liquid contained in wooden vessels. Capacious wooden vessels from the Viking era have been found in the Oseberg burial as well as others. Recent work by Dr. Pat McGovern indicates that heat-treated tree resins (including birch and juniper) were present in beverages from precursor cultures in what would become Viking-age Scandinavia.

A plausible method that joins all of this evidence would be something similar to the Finnish sahti brewing tradition. A wooden vessel (possibly a hollow log like the Finnish kuurna, or else any one of a number of large wooden barrels) would be lined with juniper branches and possibly birch. Grain biscuits and water would be added to the vessel, and hot rocks would be used to gradually heat the batch to near boiling. The liquor would then be drained off to be fermented.

4.) The Product(s)

Two types of beverages would be produced. The first was a common nutritional/medicinal beverage that would be produced with frequency, akin to the “zythum” of the Talmud and other sources. This lightly fermented beverage would double as a yeast propagation medium; the residue of this beverage would remain in a wooden fermentation vessel, and would be referred to as “gruit.”

The second beverage would be a strong alcoholic drink, similar to hydromel. Literary use and linguistic origins relate such a drink to “wine,” indicating a plausible similarity in purpose (sacrament, celebration, mourning, etc). A combination of grain, honey, and fruit was likely collected in a large wooden vessel, and some of the residue of the daily drink was added. This would inoculate the batch with yeast, enabling alcohol production. The beverage was likely sweet, owing to its probably short fermentation time and large collection of sugars.

Herbs (including hops in some locations) may have been added to the drink prior to fermentation. More than likely, the alcoholic version was reserved for special occasions, and its production was a secret known to few.

Um, excuse me, I was told there’d be beer. Excuse me?

Recreating the Past on a Budget

OK, on to the stuff you’re really after – how to do this without reading 1198 rambling words from some pontificating blowhard.

1200, now.

I’ll break the modern version down into the same steps, and go over some possible ways to interpret them easily.

Remember, all steps on the path can be valid. The important thing is to know why you’re making the choices that you’re making, and to document them for review later. It’s an excellent method of learning and developing a process while recreating an ancient technique.

Pick one option for each of the categories below, and plug ’em together. That will give you your method guidelines. From there, you can feel free to experiment by picking other options on another pass. Or invent your own interpretations! After all, I’m not the be-all-end-all on this topic.

1.) and 2) The Grains and Their Processing

Several options exist.

  • You can malt your own grain using sprouting barley or whole oats; barley is easier to find. Soak the barley in water for a couple of days (changing the water a couple of times) until it’s fat, then heap it up and turn it periodically until it starts to sprout. Drying the grain can be achieved in a smoker or on a grill using wood and peat (and dung if you’re adventurous). Grinding grain can be accomplished with a food processor – or if you’re feeling adventurous, a concrete rotary quern modeled on historical example. This will produce a coarse flour which can be made into unleavened biscuits.
  • Optionally, one can use malted barley flour (also known as “diastatic malt powder”) and add some darker crystallized grain to make a biscuit. The stuff is pricey, but if you’re willing to throw money at something to save labor, this method will allow you to make the biscuits in a fairly convincing manner while saving a bunch of work.

Picture1 Picture2 Picture3     3.) The Mashing and Formulation

Obviously, if you’ve chose to go an extract route, mashing is less important. Still, read on for general principles of recipe construction.

Based on physical evidence and batch sizes extrapolated from writings and serving vessel size, we can conclude that the Norse brewed in batches of at least 6 gallons. The ratio of grain to water is unknown, but based on glosses with “hydromel,” it is reasonable to conclude that the product would have been higher-gravity – in the 1.080 to 1.100 OG range.

This can be achieved by using a thick mash (1 qt/lb) typical of a wee heavy, or can be achieved using a thinner mash that is later supplemented with honey. A proportional recipe would more accurately reflect the processing technology the Norse likely had. An example proportional recipe could be (by volume) 1 part honey, 2 parts grain, and 8 parts water. That’s roughly 60% honey/40% malt by weight. Feel free to adjust the proportion of honey to malt as you see fit, or omit the honey altogether – it was rare and expensive then, and not everyone would have it. Smoked, roasted, peated, and crystal malts are all appropriate choices.

The most likely vessel for mashing would be a large wooden bucket, trough, or hollowed-out log akin to the Finnish kuurna. The vessel would be lined with branches from resinous trees (juniper, fir, and pine are the most common), and hot rocks could be inserted to achieve heating.

  • A reasonable way to replicate this is to add wood to your normal mash tun (or even just a big pot). Layer the bottom with birch, juniper, pine, and/or fir. Heat rocks in your oven (grill stones or garden stones work very well) and drop them in one at at time, slowly raising the temperature close to boiling. The high-intensity localized heat from the rocks will caramelize the wort, and heat-treat the tree resins.
  • Most hardware stores and agricultural supply stores will carry wood shavings, chips, and other such products. If you don’t have a source of naturally-occuring resinous wood near you, the store-bought options will suffice in a pinch. Add a good layer of various shavings to the mash and proceed as normal. Hot rocks are still a good idea for mashing.
  • If all else fails, juniper berries are usually pretty easy to find. Add some to your normal mash routine. Be generous, because their flavor can be subtle against a heavy malt bill. Direct-fire or infusion mashing will be fine, though the wort will probably not be as heavily caramelized and the juniper resins may be harsher.

Picture4Picture5Picture6 4.) The Product

Once the mash is finished, you should let the wort cool before running it into another vessel. The Norse probably didn’t boil their wort after the mash – the mash temperature is sufficient to kill most microbes, and boiling would just expend additional fuel. Aside from that, no metal or stone vessels of sufficient capacity are found to permit boiling an entire batch.

The wort was probably fermented using the dregs of fermentation of a previous batch; typically, this would have come from a medicinal/nutritional beverage that was being produced on a daily basis. This product would contain grains and herbs, and often flax or other oil seeds. Tart fruit (wild apples, polar berries, sloe, and others) and honey may have also been added at this point to add additional sugar and flavor; honey was rare and expensive for the Norse, so it would have been a very coveted beverage!

Given the lack of good storage options, the product was likely consumed very young – 3 to 7 days typically, and perhaps up to two weeks at most.

  • Use a mix of malt, appropriate herbs, and optionally some flax seeds to create a yeast propagation medium. Ferment in whatever’s handy, and add the residue (or the whole liquid if you’d like) to your batch. Give it a few days and you’re good to go! Appropriate herbs include yarrow, arctic thyme, bog rosemary, and bilberry. Hops would also have been available in southern Scandinavia and were probably used like any other flower or herb.
  • If you’re a brewer, the odds are good that you have a bucket with yeast lying around somewhere during you brew time. Rather than make a specialized starter, you can just dump the beer on an old yeast cake, and sprinkle the herbs on top. They’ll provide flavor and aroma while the old yeast will go to work on the beer. Be careful when re-using old yeast – depending on what they last fermented, they may be stressed and may ferment poorly.
  • Can’t find weird herbs? We have roughly as much evidence supporting the use of hops in Viking brewing as we do any other herb. Hops appear less frequently in finds, but they do exist. Most finds are limited to southern Scandinavia. Get yourself some whole-leaf German noble hops and use them to dry-hop the product; use about 2 grams of dried hop per pound of fermentable. Bittering hops are probably not appropriate for a Viking brew (that’s what the tree resins are for). Use whatever yeast you normally would.

Picture7 Picture8 Picture9   And there you have it! The shortcut to Viking-era beer! Now go forth and make your ancestors proud!

Zythum: An Egyptian Precursor to Beer

*tap tap tap*

Is this thing on?

So it’s been a little while since I last wrote an entry. Fear not! I’m still plugging along, brewing crazy things and writing weird poetry and telling stories about people who kill other people over beer. Good things all around! I’ve just had a double helping of Life and Such, and so things have gone off track.

Enough excuses. Back to writing.


A couple of weeks ago, I followed up on an opportunity to talk about historical brewing at a local museum. The event was focused primarily on the history of brewing in the Hudson Valley of New York, but as the museum was also running a piece on ancient Egypt, the program director wanted someone to speak about ancient Egyptian brewing.

Through some various channels, I was tapped to give a brief talk on this topic. Now, it’s not my primary area of research, but mindful readers may remember that I touched on a prospective Egyptian precursor to beer as part of my research on Viking-era brewing. I eventually settled on its existence as being somewhat central to my reconstructed processing technique, representing a yeast starter of sorts that would have been prepared daily as a medicine, and which would result in a healthy yeast culture in the residue.

One of the things I’ve begun to question is the oft-repeated “story” of ancient beer – ancient peoples are often alleged to have drunk a weak alcoholic beverage that was filled with yeast and residual grain. It is sometimes argued that this was drunk in lieu of water (an idea which I and others seriously question, and for which extraordinarily little evidence actually exists), and it is sometimes argued that such a beverage would be an extremely nutritious “liquid bread” (though we also know that ethanol inhibits the absorption of many nutrients).

What I’m going to do here is take you through my talk about a particular Egyptian grain beverage called “zythum,” deconstruct the standard story, and reconstruct a plausible alternative (which is also supported experimentally).

Because getting your historical knowledge base from popular TV can't possibly go wrong.  Right guys?  Guys?

Because getting your historical knowledge base from popular TV can’t possibly go wrong.
Right guys?

So What the Hell is “Zythum?”

“Zythum” is the Latin equivalent of a Greek word “zythos.” “Zythos” is first seen in the writings of the 1st century BCE Greek historian Diodorus Siculus, who wrote the Bibliotheca Historica. There, he describes “zythos” thusly:

κατασκευάζουσι δὲ καὶ ἐκ τῶν κριθῶν Αἰγύπτιοιπόμα λειπόμενον οὐ πολὺ τῆς περὶ τὸν οἶνονεὐωδίας, ὃ καλοῦσι ζῦθος.

Now, as evidenced in the text above, “zythos” is a-

Wait, what? You don’t read ancient Greek? Shame on you!

To be fair, neither do I, and that’s why we often must rely on translations of such writings. Here, try this:

The Egyptians also make a drink out of barley which they call zythos, the bouquet of which is not much inferior to that of wine.

The reason I point this out is that the process of translation is not a perfect one – ideas sometimes have difficulty crossing cultural boundaries, and so we must attempt to capture the “sense” of a word. Sometimes this means that we may obscure part of its literal meaning, or we may lose some nuance that is really only understood by the native culture. And of course, English has this nasty habit of grabbing older words from other languages to talk about lots of things – so sometimes we use an older word from another language to talk about a thing that we do, even if our practice differs from the old one. Keep that in mind as we proceed.

OK, so! If we look at this one source, we can see how one might reasonably conclude that “zythos” is an analogue to beer, right? Diodorus compares it to wine on the parameter of its bouquet, so perhaps we could reason that the two must share some commonalities. I mean, why compare it to wine if it wasn’t being used like wine, right? And it’s made of barley, so we have the possibility of an alcoholic drink made of barley. Heck, even the actual word “zythos” gives us a clue as to its nature – it’s closely related to lots of other words that indicate leavening.

So a barley drink that is related to wine and that is leavened? Sounds like beer to me!

But it’s a poor researcher who limits himself to one source. Let’s look for other evidence of Egyptian barley liquids:

From the Greek historian Herodotus in the 6th century BCE:

For wine, they use a drink made from barley, for they have no vines in their country.

Well, there it is again. We have evidence of a barley drink that is related to wine. Seems that one could draw a line from “zythos” back to at least the 6th century BCE, right? So there we go, reinforcement that “zythos” is beer and it goes back a ways.

Well, not so fast, cowboy. See, “wine” doesn’t have to mean alcohol – that’s our most common sense of the word, but in ancient Greece and Rome, “wine” was used to refer to several different products of the vine. Cato the Elder gives a “wine” recipe in De Agri Cultura that involves diluting the must 1:5, adding seawater and vinegar, and waiting a bit. It makes an excellent vinegar after a fashion. Doesn’t really sound like merlot, does it? And in many places, the juice of grapes is called “wine” as soon as it is pressed – the fermentation doesn’t seem to be the critical factor there. So while Herodotus talks about “wine” and Diodorus talks about “wine,” there’s no guarantee they’re talking exclusively about a strong alcoholic beverage.

Let’s move on. How about Hippocrates, the father of medicine? He wrote an entire treatise on the use of barley in remedies in the 5th century BCE:

Ptisans are to be made of the very best barley, and are to be well boiled, more especially if you do not intend to use them strained.

Fun fact: “ptisan” is etymologically connected to “tisane,” which is a term we use to refer to “teas” made of things that don’t actually involve tea leaves. Neat, huh? Also as a side note: Hippocrates mentions that people routinely refer to various remedies over-broadly, lumping several different things together under a single name. Something else to think about when you read about “wines” made of barley, eh?

But it seems like we’re seeing alternate uses for barley drinks – here, a medicinal beverage is concocted.

How about we jump ahead a bit to one of my favorites, Pliny the Elder, who wrote Naturalis Historia in the 1st century CE. I’ve talked about many of his writings in various places on this blog, but there’s one in particular that is of note here. He discusses a variety of non-wine beverages made from grains:

Different beverages, too, are made from the cereals, zythum in Egypt, cælia and cerea in Spain, cervesia and numerous liquors in Gaul and other provinces. The yeast of all of these is used by women as a cosmetic for the face.

Several things are notable about this statement. For one, the specific chapter in which this is found is in a book that deals with medicinal remedies derived from plants (book XXII). Pliny also discusses “wines” of grain in a completely separate section (book XVIII), and it is clear that these are distinct types of beverages.

“Zythum” is the Latin equivalent of “zythos,” and here we see Pliny discussing it. So now we have yet another possible view of the drink.

One should also note the other listed beverages. Pliny is calling them different things, but sort of lumping them together in the same functional category: a book all about remedies from plants discussing several beverages in the same sentence hints at a similar function. The word “cervesia” is notable because similar words are used to mean “beer” in modern Romance languages. Yet here, it is clearly discussed outside of a “wine” context and in a remedy context.

We also see a common utilitarian purpose; the “yeast” (actually, the word was “spuma,” which means “foam” – one of those interesting translator choices again) is used by women as a facial cosmetic. Such a use may indicate a more frequent production, assuming Roman women were applying facial cosmetic regularly. In order to use it so, there’d have to be enough kicking around frequently enough.

And of course, the mention of “spuma” may help indicate a possibly fermented beverage – but one that is not as strong as wine, and which is used for remedy/utility purposes.

Well, now I’ve done it. I’ve gone and muddied the waters that had previously been clear and over-simplified. While one might be able to look at the evidence for “zythos” and argue for an alcoholic beverage, a more careful look at additional evidence calls that into question. It seems to be related to medicine (and the use of barley medicine is quite old), is noted separately from “wine,” and even the word “wine” may not mean what you think it means.

Many people, in times of confusion or need, have turned to various holy books for guidance. While I don’t normally put stock in such things, it seems that it will take a miracle to resolve this confusion. Let’s see what the gods have to say about this.

"Thou shalt not fruit thy beer, for that is totally lame and only appropriate for yellow swill in clear bottles."

“Thou shalt not fruit thy beer, for that is totally lame and only appropriate for yellow swill in clear bottles.”

The Babylonian Talmud contains numerous laws, and in Pesachim 42b, we find this written:

What is EGYPTIAN ZITHOM? — R. Joseph learned:  [a concoction made of] a third part barley, a third part safflower, and a third part salt.  R. Papa omitted barley and substituted wheat.  And your token is ‘sisane.’ They soaked them [these ingredients], then roasted them, ground them and then drank them. From the [Passover] sacrifice until Pentecost, they who
are constipated are relieved, while they who are diarrhoeic are bound. [But] for an invalid and a
pregnant woman it is dangerous.

The specific section in which we find this is a list detailing additional specific items which must be removed during Passover because they are chametz (typically meant as “leavened,” but Jewish law calls grain chametz in many other circumstances). One explanation for such a list is that they are mainly items which may be in the house, but whose manner of preparation is not known to the keeper of the house. Perhaps they are purchased from elsewhere. It would also seem to follow that the products must not be obviously leavened or fermented, or not obviously grain-based – otherwise, it would be obvious to remove them.

Note that a medicinal use again is indicated, and no specific mention of fermentation is made. One could suppose a sort of fermentation may happen (it is in a book talking about taking leavened things out of the house), but grain is chametz when mingled with water for 18 minutes – so it doesn’t have to be fermented.

Well, OK, so it may or may not be fermented. Probably isn’t obviously fermented, and given the high salt content (more about this later), the stuff would have to be fairly dilute to be reasonably drinkable – so it wouldn’t ferment far if it even did. In fact, it seems like the salt may be an attempt to control the fermentation – either it’ll be too salty to ferment but have a lot of calories from grain, or it’ll be too dilute to have appreciable alcohol.

Now let’s try something from the 10th-century Islamic empire. Here’s a recipe for something called fuqa (lit. “bubbly drink”) from a translation of an ancient cookbook:

Boil water, enough for making 50 beer glasses, and pour it on the malted barley. Stir and mix until only barley shells remain. Set it aside to cool down then strain it and take the amount enough for making 50 beer glasses. Add a suitable amount of salt (pure and white rock salt) so that the beer will be neither too salty nor bland. The best way to judge is for the beer-maker to taste it. Set the liquid aside until it settles and looks like clear water.

The recipe calls for ~1.1 kg of malted barley. A “beer glass” may have been as large as one cup (~250 mL) in capacity, so this recipe could be looking to make up to 12.5 L of liquid from 1.1 kg of barley malt – about a 1.022 OG assuming flawless extraction. That’s not very much at all. Also note the salt addition – seems reminiscent of the Talmud method, eh? And of course, the very beginning of the chapter about fuqa talks about the medical use of barley water – so again we have a medicinal context.

Here, you are ultimately instructed to sort of ferment the beverage – you leave it for 12 hours in a jar that was previously used to brew beer. The text warns against using the same jar too many times – it must be discarded once fermentation is apparent. So again we see evidence of a processing technique that may involve a weak non-obvious fermentation of a very dilute beverage.

Christian scholarship may also give us some clues. A 19th-century German scholar of ancient medicine found a fragment of text that was attributed to Zosimos of Panopolis, a 4th century CE Greek alchemist. You may recall that I discussed this before in another post, but I’ll repost the method here:

Take good pure barley and water, and soak it for a day. Spread it out and put it in a windy place for another day. Again soak it for 5 hours, then collect it in a sieve with handles, and soak it again after it has drained until it becomes puffy.

When this is done, dry it in the sun, until it deflates: The husk is indeed bitter.

Now mill (it), and make a bread-dough, adding leaven as in bread-making, and bake it very well. Then boil it well, and separate the sweet water, straining it through a sieve.

Some heat toasted bread in a pan with water, and cook it a bit, but neither must he boil it nor heat too long, and taking it from the fire, transfer to other vessels, and again heat and reserve (the liquid).

So now we’ve got a bread beer thing that also doesn’t talk about fermentation. Sounds an awful lot like Russian kvass, eh?

Hm. Based on my reading of all this information, I’m putting together a different picture than that oft-repeated story about daily beer. What I’m seeing is evidence of a non-or-lightly fermented beverage akin to a kombucha or kvass, probably made with a weak dilution of grain (and possibly herbs) and salt, that was used as a medicine and common drink. A lot like a fermented barley tea.

And that makes sense when you boil it down, doesn’t it? We know that alcohol is a diuretic, and that it lowers blood sugar, and that it has all kinds of properties that make it nutritionally deficient. At least two full processing methods seem to attempt to minimize ethanol production.

Imagine this: you’re the guy in charge of building the pyramids, and you’ve got your team with you (evidence suggests that the pyramids were actually built by skilled laborers and not slaves as previously thought). It’s hot as hell, and they’re hauling really heavy blocks. Do you want them drinking something that will dehydrate them and drop their energy levels, or would you give them a drink that is mostly water with added electrolytes (salt), carbohydrates (sugar and starch from the grain), B vitamins (assuming a light fermentation, yeast will grow and contribute nutrients), and possibly some poorly-controlled medicinal effects (herbs)? Like drinking pickle brine when you’ve been in the hot sun all day.

When you get right down to it, the idea of daily booze doesn’t make sense, and the evidence really seems to support this sort of fermented tea process.

But that’s all talk. How about some experimentation?
IMG_20140406_164412IMG_20140406_165116IMG_20140410_193602IMG_20140409_081031IMG_20140411_190512 IMG_20140411_192121























Equal parts barley, salt, and safflower (by volume), steeped in water until it was fully saturated, dried as per the method attributed to Zosimos. I was curious about the salt content, so I did a version with salt and another without. Picture 2 is the salted version; picture 3 shows the unsalted version, which began fermenting not too long after being submerged in water. This reinforces the idea that the salt content is at least in part intended to control fermentation.

The mass of stuff I started with in 2 was 134 g; after drying, I had 157 g. The unsalted version gained no mass at all. This indicates to me that the grains took up 23 g of salt during processing – giving a final salt content of roughly 15%.

That’s really damn salty, so I diluted the grains 1:10 as per the method indicated in the Islamic text. That would reduce the salt content in the drink to 1.5% – probably a manageable level. I also wanted to know about fermentation or not, so I did a Punnet square: salted/unsalted and fermented/unfermented.

What I discovered is that the beverage didn’t generate any alcohol at all, not even after days of fermentation. It did encourage yeast growth, and the salted/fermented version tasted something like chicken soup after about 24 hours. The unsalted version were flat and boring, but the salted version were pleasantly full – not quite as strong as pickle brine, but definitely filled with electrolytes. After enough time, the fermented versions became somewhat sour, but not unpleasantly so.

Really, this is like an ancient form of Gatorade. It’s all manner of not bad, and I highly recommend trying it! The high salt content seems to necessitate an extreme dilution of the stuff, and if it was being consumed every day, it really wouldn’t have time to make alcohol. When post people think of a “low alcohol” beverage, they mean 2 – 3% ABV, but I am talking about a drink that is literally non-alcoholic – probably under 0.5% ABV.

The most interesting part of all of this is the connection to other words that we translate to mean “beer.” I’ve used that connection to suggest that this processing method carries forward into Viking-era brewing – a grain/herb mixture fermented frequently, whose residue could be used to start a strong beverage. Makes sense, right? You’ve got a yeast propagation medium with a strong connection to health and cleanliness – seems like the kind of thing that would make a pure beverage, right?

And maybe this technique carried into the Germanic tribes outlying Rome, and maybe some brewers out there saw some pretty flowers growing around a tree and thought, “Man, I bet those would go well in that grain tea I love so much.” Maybe that’s how hops entered the equation all those years ago.

Of course, none of this analysis precludes an alcohol interpretation, either. “Wine” can mean a lot of things, and that includes wine. So maybe there were several traditions that existed at the same time. Maybe the daily beverage existed and a strong beverage was made as well, and both were called “zythos.” Hey, Bud Light and Sam Adams Utopias are both “beer,” right?

This is why we have to interpret archaeological evidence, and consider the paradigm under which we are operating – because sometimes we bring our modern biases into history, and they just don’t belong there.

This is perhaps how beer actually saved the world.

Historical Brewing 201: OK, Sometimes, It’s as Hard as You Think

I’ve talked at you all before about how easy it can be to do historical brewing research and recreation. We often attempt to take the principles of period processing methods and attempt to translate them into modern methodology, to give  a sense of historical practice by varying the familiar.

We can also alter ingredient bills, to attempt to emulate the flavor profiles that may have existed at the time. This is all well and good, and it’s an important part of the process of experimental recreation.

Sometimes, though, the task is not so clear-cut, and attempting accurate recreation becomes a real challenge. How were the ingredients grown? What units of measurement were at play? Water quality? We can’t always answer all of these questions, but the attempt to do so can yield valuable information, and the process of extrapolating will teach us things whether or not we get a useful end-product.

So let’s talk about wood.

Wooden Bottle

(Archaeological Museum of Baden-Württemberg. Photo: Manuela carpenter – click for a link to the gallery page)

This bottle is part of an excavation of Trossingen grave 58, a find in Germany that dates to the 6th century CE. The picture above links to a gallery of the find.

This bottle is identified as a vessel with the remains of a hopped barley beer. This is sort of A Big Deal in the historic brewing world, because this would constitute the oldest existing physical evidence of the use of hops in a fermented beverage ever found. Not only that, but this is solid physical evidence of the use of hops a good 500 years before we had thought hops were really coming into use. This find has the power to really re-shape what we think of the history of brewing and hopped beverages. Neat stuff.

There is a publication which details the find (and its numerous artifacts) which you can obtain here; of course, the entire thing is available exclusively in German, so you may have to find a linguistically-inclined friend to help you out with it. Fortunately, I have some connections, and I managed to acquire the part of the journal detailing the bottle find. A bit of OCR, Google translate, dictionary consultation, and linguistically-inclined friend consultation, and I managed to figure out most of what the find was about.

Evidently, there was pollen residue in the bottle (~3500 grains), and researchers were able to identify the sources of the pollen grains:

Gut 17% davon stammen von Getreide, wobei der Gerste-Typ überwiegt. Getreideunkräuter machen zusammen fast 11% aus, Hopfen und die Weinrebe sind mit jeweils 0,4% vertreten. Mit gut 29% die größte und auch die artenreichste Gruppe sind Pflanzen…

If my translation is right, the contribution is 17% barley, 11% cereal weeds (possibly rye or oats?), 0.4% hops, 0.4% grapes, and 29% “bee pollen” (which is taken as a marker of honey). The bottle also contained evidence of fermentation (oxalate crystals), and so the author concludes that the beverage was probably a mixture of the above ingredients in the mentioned proportions, fermented together and hopped. The beer came first, and it was “enriched” with honey – or so the author concludes.

But I don’t like that analysis. For one thing, the author doesn’t seem to try to figure out the actual proportions of the plant matter represented by the pollen; the text seems to assume that all ingredients will convey the same amount of pollen, which may not be the case. They also don’t elaborate too much on their rationale for their experiments or on the type of hop present – which is too bad, because this is a pretty big find!

So let’s tear this down and show how you can extrapolate a recipe from scant information. What if you wanted to try recreating a beverage like this? No recipe, no method, just some pollen grains in a bottle – how can we do it?

Watch and learn.


That feel whenever you take off autopilot and try to land the science jet yourself.

When we do this kind of analysis, we often have to make lots and lots of assumptions and extrapolations. In archaeology, the variables are often well beyond our control – so experimental archaeology must try to control what it can or accept the limitations of uncontrolled variables. I’ve advocated a sort of “mapping” approach to redacting and analyzing ancient recipes, and that principle will aid us here as well; by listing out my assumptions and reasoning, I can go back and nitpick and refine and strengthen my arguments.

The goal here is to get to something that resembles a more accurate technique, and in the process to enumerate some other possible and plausible methods. Most of the time, these sorts of analyses are rarely definitive, and tend to leave us with more questions than when we started – but it helps us to focus our inquiries, so that our questioning can be more productive. This is the heart of science.

Let us assume:

1) That a total of 28% of the 3500 pollen grains are attributable directly to barley which has been malted (that would be 17% attributed mostly to barley and 11% attributed to “cereal” weeds – we know that barley is not generally insect-pollinated, so the “bee pollen” probably does not cross with this group);

2) That 29% of the pollen grains are attributable to raw honey (bee pollen shows up often in raw honey);

3) That 0.4% of the pollen grains are attributable to Hallertau hops (they’re alleged to be the first hops that were ever domesticated, and the Trossingen area was close-ish to Hallertau);

4) That 0.4% of the pollen grains are attributable to grapes (though as you will see shortly, I haven’t rolled grapes into my analysis yet because I can’t find information about them);

5) That the ingredients were fermented together in a single beverage (as opposed to the pollen contribution coming from, say, 3 different beverages which all touched the bottle at some point);

6) That a single kernel of barley (which contains three anthers) will produce ~4500 pollen grains, about half of which can be removed relatively freely – so ~2250 pollen grains will survive through malting and will make it into the final beverage;

7) That a single kernel of dry barley weighs one grain (0.06 grams – the origin of the term “grain” is the weight of one kernel of barley), and that malted barley is ~10% less dense than unmalted barley;

8) That raw honey contains, on average, 6000 pollen grains per gram (based on estimates of average pollen load of “normal” New Zealand honey);

9) That hops used were wild, and thus grew at a ratio of 1:1 male:female plants (hops are a dioecious plant, and wild-type examples of such plants grow in a ratio pretty close to 1:1 – this indicates that the pollen load of a male plant reported represents a single female flower);

10) That hops pollinate in a manner similar to their nearest botanical relative, Cannabis (note that hops are a cannaboid) – which produces an average of 36,500 pollen grains per male flower;

11) That the mechanism of wind pollination results in ~95% of the pollen accumulating on the windward (i.e. exterior) surfaces of the plant, and that this pollen load would be removed in hop processing (i.e. the pollen that didn’t make it into the interior of the female flower just falls off);

12) That there are 100 wet hop flowers (we use the female flower of the hop in brewing) per 50 grams of hops, or 0.5 grams wet per hop flower (which translates to roughly 0.1 grams per dried flower);

13) And that these estimates actually apply to 6th century German plants.


Y’know, I never noticed the completely incredulous look on his face until right now.

So, basically, I’m making shit up. “Educated guesses” if you’re feeling generous – but I’m basically winging it in the absence of any more useful information.

One thing that we can definitely see by my analysis so far: it is a great mistake to assume that all of the ingredients going into a beverage would have the same pollen representation per gram.

Let’s look at my numbers. Each barley grain produces 2250 pollen grains, each gram of honey has 6000 pollen grains, and each hop flower has 1825 pollen grains (5% of 36.5k). Let’s convert these to a standard measure: pollen grains per gram of plant matter.

Barley: 37.5k pg/g
Honey: 6k pg/g
Hops: 3650 pg/g

Now, how about the proportional representation of pollen grains in the find? 3500 pollen grains total, so:

Barley: 28% = 980 pg
Honey: 29% = 1015 pg
Hops: 0.4% = 14 pg

And then we just do the math to figure out the possible mass of plant matter that delivered that pollen load!

Barley: 0.026 g
Honey: 0.17 g
Hops:  0.0038 g wet (1/5 as much dried)

That gives us a ratio of barley:honey:wet hops (by weight) of 26:170:3.8, or to make things easier: 7:45:1

So let’s turn this into amounts that make more sense, shall we? Let’s also not forget that malted barley weighs 10% less than “green” barley:

63 g malted barley (about 2 oz)
450 g honey (about 1 pound)
10 g wet hops (2 g dried)

The first thing I notice straight away – this ain’t a barley beer. Not by any stretch. The mass of barley is so small that it really seems much more like a flavoring or additive than anything else. The vast majority of sugar here is coming from the honey – enough that I’d really call this a “mead.”

Of course, as you will remember, the word “beor” (which is a root of “beer”) is glossed with “hydromel,” which refers to a honey-based strong beverage. So really, it’s not outside the realm of possibility that one could call a honey-based drink a “beer” in the ancient world – it seems to have fulfilled that role.

In fact, the amount of barley is so small that I really think about a starter biscuit more than I do an actual source of grain sugar. Remember how I’ve been hypothesizing about Viking-era “breads” really being used as yeast starters? This may be the sort of thing I’m looking at here. And remember how I’ve talked about those same breads really being grain/herb mixtures? And how that grain/herb mixture, once fermented, could be used as the basis for fermenting a strong drink?

Pliny specifically discusses the various methods of making “leaven,” and one method is to incorporate grape must into barley flour and make a biscuit. Grape must incorporated into such a “bread” as I’ve talked about previously could explain the grape pollen in the original find. The use of herbs in the bread may give us a clue as to how the hops came into play; perhaps grape must and hops were mixed into barley flour, and the resultant “cake” was used as a yeast starter to then ferment a honey/water solution.

We can make a wide number of recipes simply by varying the amount of water that goes into such a thing. Generally, “hydromel” was a 1:4 honey:water ratio. A pound of honey occupies a space of about 10 fluid ounces, so we’d need about 40 fluid ounces of water to properly dilute that honey. Do that, add in your 65 grams of barley/dried hop mix (which has been previously fermented), and wait a bit. Yeast from the grapes eat those sugars, and you get a little more than a quart (about 1.5) of slightly hopped mead.

How hopped? Well, 2 dried grams of hops at that density of sugar yields ~12 IBU – roughly the same bittering content of Budweiser. For reference, an English Ordinary bitter is somewhere in the 25 – 35 IBU range. American pale ales are in the 50’s, and IPAs are up in the 70’s or more.

You could even add a bit more water – maybe go to half a gallon of final volume (1:5 ratio) with all that honey, which would give you a lighter-bodied beer with only 8  IBU. A little less sweet, a little less hoppy. The evidence still supports such an idea. Hell, it supports a lot of ideas.

Or you could go heavier (1:3 ratio) and make something really sweet with about 16 IBU. It’s all up to you and what you prefer!

Therefore, based on my analysis of the evidence, I conclude that the Trossingen bottle may have contained the remnants of a lightly hopped mead, which may have been fermented using the residue of a light grain fermentation.

Possible OG (Original Gravity) Range: 1.059 – 1.120
Possible bitterness (IBU) Range: 8 – 16
Possible volumes (quarts) Range: 1 – 2


The lesson here: archaeological evidence always requires interpretation. Using the same set of facts, we can come up with very different conclusions simply by varying the manner of our interpretation and the set of assumptions used to perform an analysis.

This is far from a definitive answer. I have thirteen listed assumptions, any variation on any of which can completely alter my outcome. I have no idea how much water was added, or how long it was fermented, or what proportion the grapes represent. We could re-analyze the model with an attempt to figure out what “cereal weeds” means and re-evaluate the contribution of plant matter from those (here’s a hint: rye produces ~10x the pollen that barley does – so there may be even less grain in this recipe than I’ve indicated).

But at least for now, I have something to work with – and that’s how science works.

Cooking with Njall: Burn Baby Burn! Salt-Burn, Anyhow.

As you will remember, I’ve been screwing around with Viking-era salt production methodology. Based on a review of the language and literature, scant archaeological evidence, and good ol’ fashioned guesswork, I’ve been cobbling together a method that involves steeping kelp ashes in water in order to extract their mineral essence. That link back there is proof-of-concept. It can work, at least in principle. Cool, right?As a scientist, I’m never satisfied with an answer. Ever. It’s kind of like the Creator’s Curse, in a way – in the process of investigating a hypothesis, we learn things that often cause us to alter our understanding of that hypothesis. Rarely are you “right” at the outset. More often than not, you’ll be confronted with how the magnitude of how little you actually knew at the beginning – because you’ve gained knowledge in the process.
So we’re doomed to keep asking questions about things we’ve already investigated over and over again, because dammit we just keep learning new things.
Knowing that it’s possible simply isn’t enough. I need to know how well the method works. Is it actually feasible at a production level? Would it make sense from a fuel consumption standpoint? How hard is it to pull off? What kind of product is left behind? These are all things that we can investigate through experimentation and review, and that’s what I’m starting on here. Investigation! Skeptical inquiry! Lighting shit on fire! All the best aspects of science!
Bro, do you even science?

Bro, do you even science?

In order to investigate plausible extraction methodology, I wanted to test two different factors: water source and heat of extraction. Previously, I simply soaked charred kelp in room-temperature water and boiled the runoff. That’s great, but we also know that the solute holding capacity of water increases with temperature – so hypothetically, a hot water extraction should allow more salts to dissolve than a room-temperature one.

I also used water from my tap, which is all good and well – but this is a utility endeavor, and it was practiced on beaches isolated from major population centers. Would a salt-karl really haul fresh water from somewhere just to make salt, or would he use the seawater that’s right next to his setup? Remember, Pliny indicates that many cultures (including various Germanic tribes) made salt by evaporating seawater, and some by pouring it over the hot coals of wood. It’s plausible that seawater plus ashed kelp could be used to produce a salt; Atlantic seawater is only 3.5% salt in composition, and the saturation point for a saltwater solution is around 26% (barring any hypersaline water oddities).

Before I could do anything, though, I needed to burn some shit.


For a dude who writes about Viking stuff, you’d think I’d have more pictures of things on fire.

As I’ve mentioned before, I bought 50 pounds of Icelandic kelp meal some time ago. Since then, I’ve been trying to figure out a way to effectively burn the stuff. The configuration makes it useless as a fuel item; a friend had suggested burning it as food, and even offered up the above-pictured Lodge cookware for it. The test-run many moons ago was successful but stinky – I figured my 60,000 BTU propane burner could get the job done.

Man, did it ever. My previous efforts never resulted in significant combustion, but this stuff really took off after the initial heavy smoke phase. Interestingly enough, it also burned out and never re-ignited; my guess is that most of the carbon content burned off, leaving behind mostly mineral salts. The fire itself produced a fairly noxious-smelling black smoke, with a chewy oily texture.

Let me just reiterate how awful this shit smells. It’s extremely smokey, takes a while to burn off (I think the pot above smoked for 45 solid minutes before catching fire), and smells like a rotting whale carcass stuffed with fermented shark that is also on fire. Also the whale is on fire. Also the entire ocean is on fire.

It’s really not pleasant.

Seems there’s a good reason that “salt-karl” was an insult, and why the Norse did this on a beach well away from other people. When I came in after 3 hours of burning stuff (during which I reduced 12 lbs of kelp to ~5 lbs of ash), my fiancee could only say “UGH. What’s that smell?” And today, two days later, my peacoat still reeks.

A Sunny Day

You could smell it at the porch, and 1/4 mile into the woods down our walking path. Also STANDING NEXT TO IT FOR 3 HOURS.
Man, if only we could BUY salt or something.

So after I finished standing outside freezing my ass off while inhaling fumes of unknown toxicity, I had a tub of charred stuff that smelled fairly awful. It needed to cool overnight before it could really be useful – ashes tend to stay warm for some time. They never fully ashed, not even when combusted – but again, I believe that to be a byproduct of the configuration. Future experiments will look at trying to use sheet kelp as an actual fuel source, rather than expending heating fuel to make ashes.

Once you’ve got cooled kelp ash, it’s time to extract the mineral content! I’m used water as an extraction medium, and tried both conventional tapwater and a seawater analogue consisting of 3.5% salt.

Charred Kelp AshBoiling Water The Setup

It’s always prudent to assemble your materials before you proceed with an experiment. Here, I’ve procured my kelp ashes (~2.35 kg), propane burner and propane (set to 50% maximum output), several measuring containers, a strainer and bowl, and of course a kitchen scale.

The faux seawater solution was prepared by combining 5 kg of tapwater with 175 g of kosher salt, giving a final salt concentration of ~3.5%. Note that I weighed the water as opposed to measuring volumetrically – that’s because water has a density of 1 gm/cm^3 (until it gets near freezing, at least), so that 1 gram = 1 mL and 1 kg = 1 L. Convenient! My scale has better resolution (minimum 1 g) than my volume equipment, so this will allow for maximum accuracy.

Controls are crucial in any experiment, and it’s important to identify needed controls at the outset of an experiment – let your hypothesis govern the choices. In this case, I’m specifically looking to assess the difference in extraction efficiencies between 1) salt and fresh water and 2) low-temperature and high-temperature extractions. Because I will ultimately be measuring a mass of solid product, it’s important to know what will be contributing solids to the extracts. In order to provide controls, I boiled down 1.5 kg each of tap water and “seawater” and measured the mass of residue that could be removed from the pan.

Hard Water Residue Saltwater Aftermath

On the left, you can see the residue remaining from boiling off tapwater. We’ve got hard water here (perfect for brewing), so it’s not surprising that there is a scale left on the pan. However, it proved to be too little to effectively harvest or measure, failing to register any mass on my scale. Thus, 1.5 kg tapwater contributes less than 0.5 grams of solids to final counts. On the right, we see the residue of the “seawater,” representing the base contribution to the method as well as accounting for the losses that invariably occur when trying to harvest the salt.

1.5 kg of saltwater with a concentration of 3.5% salt by weight yielded a final salt load of 46 grams. Hypothetical yield was 52 grams, but some salt was lost in processing. Still a fairly efficient extraction. The salt was initially rather wet after drying – something like 70 grams and a consistency not unlike brown sugar – but it was heated in the microwave for 1 minute to fully dry.

For sample setup, I basically drew a Punnet square and did the appropriate combinations. 4 500-gram portions of kelp were measured into appropriately-labeled dry containers. 1.5 kg of either salt or fresh water was added to each sample. Two of the samples (one fresh and one sea) were left to steep at room temperature for 30 minutes, while the other two samples (fresh and sea) were heated in a pot on the kitchen stove. Heated samples were brought to a visible boil, and dropped to a simmer for 5 minutes after the first bubbles breached the surface. Following all extractions (whether heated or room temperature), the water/kelp masses were strained through a wire mesh strainer, and the liquid phase collected. The kelp mass was allowed to drain for 5 minutes, ensuring collection of a significant portion of the liquid.

Steeping Kelp Hot Water ExtractionDraining the Stuff

I didn’t measure the volume of runoff from each (though now I’m wishing I had) since I was only focusing on final solid extract generated by the methodology. However, all 4 extract methods appeared to produce roughly the same volume of runoff – roughly 400 – 500 mL. Future experiments will more accurately determine runoff volume generated by these extraction methods.

Once extracts were obtained, they were boiled down as the controls were. The pan was washed and dried in between each boiling (actually, all common equipment was thoroughly cleaned and dried in between samples to eliminate the possibility of cross-contamination), and the same equipment was used to extract the salt from the pan (i.e. a spoon and a spatula). Extract mass was determined using the same scale used to measure all of the ingredients. In order to standardize the moisture level, all samples were microwaved for 1 minute after collection as the saltwater control was.

KRF The Aftermath KRS The Aftermath

KHF The Aftermath KHS Aftermath

I devised an abbreviation scheme to represent the four sample configurations. All samples are identified by three consecutive letters indicating their combination of treatments: K/[R or H]/[F or S], indicating [K]elp, [R]oom-temperature or [H]igh-temperature extraction, and [F]resh or [S]altwater extraction. Top row from left to right shows the solids extracted from KRF and KRS; bottom row from left to right shows extracts of KHF and KHS.

Yields for all samples and controls are given below. Compounded uncertainty in measurements is +/- 1.5 g; the scale has no listed uncertainty of its own, and 10 consecutive weighings of identical volumes showed no deviation. Uncertainty is thus half the value of the smallest unit of measure (1 g), added for each step that involves weighing. In this case, 3 different weighings of different components were used to determine the components of the extraction process – their uncertainties add together.

Sample Name                            Mass of Extract (+/- 1.5 g)

Saltwater control                     46 g

Freshwater Control               <0.5 g

KRF                                            42 g

KRS                                            112 g

KHF                                            90 g

KHS                                           120 g

The results are not terribly surprising. Both of the hot water extractions yield more salt content than the lower-temperature extractions. The difference is greatest when using fresh water for the extraction, which indicates that the charred kelp contains quite a lot of salt to potentially extract. It is curious that the yield from KRS is larger than [KRF + Saltwater]; one would expect that the yield would simply be additive and thus the two would be mostly equivalent.

It appears that the high-temperature extraction with salt water yields the largest quantity of salt, but the gain from heating is minimal compared to a simple room-temperature salt water extraction. It appears that the use of salt water for extracting leads to the greatest gains in salt yield. This is unsurprising, as the salt water contributes a significant salt portion. It may be that the addition of charred kelp to salt water allows the solution to approach saturation; assuming 500 mL of final volume, the KHS solution would have had a solute concentration of ~24% prior to boiling.

Recovery efficiency seems to decrease as final salt mass increases. When evaporating KHS, several larger globs of salt “popped” out of the pan in response to heating. This phenomenon was observed in other extracts, and is generally exacerbated as the amount of salt condensing increases. This may also account for the observed decrease in effectiveness of heating in extracting additional salt from the kelp.

Ultimately, this demonstrates the utility of using kelp ash to increase salt yield from boiling seawater. 1.5 kg of seawater, when boiled off, yields 46 g of salt. The addition of kelp ashes to that same mass of seawater, while reducing final liquid volume, can increase the final salt yield by a factor of approximately 2.5, for a maximum yield of 120 g. This has the potential to consume less fuel (boiling a smaller volume of liquid) while simultaneously increasing salt yield.

It should be noted that expending fuel specifically to ash the kelp is likely a fuel-losing prospect. More than likely, sheets of dried kelp were themselves burned as a fuel source, and the ashes collected and used for various home purposes.

So what’s next? Fuel consumption estimation, liquid extract volume yields, experimenting with sheet kelp as fuel, additional experiments for the sake of rigor…

But before that, I’m a Norwegian, and I have salt. Let’s get some cod and see what happens when I apply kelp-ash salt to it. Next time, we’ll see how that works out.

Final Products

Seriously guys, just buy your salt. It’s way cheaper and your clothes won’t smell like a terrible tragedy at the docks.


Element symbol: amount (ppb)
Note: BDL = Below Detection Limit
1 PPB = 1 ug/kg

Kelp Salt

V: 386.0
Cr: 491.6
Co: 180.0
Ni: 342.2
As (total): 574.2
Mo: 913.8
Cd: 186.3
U238: 96.01

Control Salt (Kosher Salt boiled in a pan)

Cr: 361.6
Ni: 225.6
As (total): BDL
Pb: 79.08
U238: BDL

The arsenic (As) level was not speciated, as it was not considered a level of general concern for salt.

The FDA sets a level of concern for arsenic in juice of 23 ppb, at which point the arsenic must be speciated. Inorganic arsenic in juice has a tolerance level of 10 ppb.

The US does not set an arsenic standard for any other product.

Codex Alimentarius maintains internationally-recognized standards for contaminants in some products:

The standard for food grade salt is 500 ppb total arsenic, so this slightly exceeds that. However, they also note that marine products (seafood and kelp) routinely have higher levels of arsenic (mostly organic, with ~1 – 3% as inorganic), often up to 50 mg/kg (50,000 ppb).

A 2007 study by Amster et al raised some concern about arsenic in kelp supplements, but was highly criticized because it failed to speciate the arsenic, and thus could not demonstrate the toxic link it claimed. The paper also suffered other severe methodological flaws.

In general, the amount of arsenic observed in the salt is not of concern. 10 g of the salt (twice the RDA for sodium) would contain 5 ug of arsenic, well within the typical human daily consumption range. And it is unlikely that all of the arsenic is inorganic – most is likely the organic (non-toxic) form, rendering the salt largely non-toxic.

But I would not use this salt as a day-to-day table salt, to be on the safe side. As a preservative for fish which is likely to be soaked out, it should be fine.

Thanks to Tom King and the chemistry division of the NYS Department of Agriculture and Markets Food Lab!

Brewing with Egil: On Nordic “Grog” and How I (Sort of) Totally Called It

A mid-cycle update?! Madness! Pandelerium! Falling skies and cohabitating felines and canines and other social currency references!

Several people have pointed me at some very recently published research coming from Dr. Pat McGovern regarding Norse brewing. If you’re a nerd like me who is conversant with science, the paper is available for free from the journal – ain’t open access grand? McGovern’s analysis of biochemical residues reveals that the ancient Danes may have drunk a concoction of honey, grains, local fruits (cranberries), possibly imported grapes, and local herbs.

Sound familiar? Well, it did to me – because I reached this conclusion independently in February 2013. I presented it as an SCA class in April of 2013, and of course I made my poster a bit after that.

Yeah, I totally called it.

Physical evidence? I don’t NEED that.

But who’s counting, right? Certainly not I. Truth be told, I was not the first person to come to that conclusion; Ian Hornsey reached a similar conclusion in 2003 in his book  A History of Beer and Brewing.

Until now, the primary issue in figuring out Viking-age booze was the small matter of a near-complete absence of physical or written evidence. No finished product has been recovered, no obvious brewing facilities have been found, and few pieces of ancillary equipment exist. In addition, there is no written method documenting any alcohol production by the Norse – they weren’t a writing-centric society, and even the few written works that do exist don’t bother with something as simple as alcohol production.

My research pulled together linguistic, literary, and indirectly-related archaeological evidence to build a plausible paradigm for Viking-age brewing – including figuring out what ingredients may have gone into it.

McGovern’s findings represent the first complete physical evidence pointing to actual ingredients that may have plausibly been involved in producing Norse alcohol – and that evidence completely supports the hypotheses I’ve been developing for over a year now!

Now, granted, the time period of his findings pre-dates the age of the Vikings – but my current research combined with this new evidence makes a very compelling case for its continuation. In addition, the presence of multiple sugar residues in a vessel is not de facto evidence that all of those were mixed into the same beverage – but considered in conjunction with my research, the case is certainly strong that it was probably being done. And the residue evidence is still not evidence of any particular processing technique – so the paradigm and processing research I’ve done is still fairly speculative.

Really, it’s the processing and goal that matter the most; a brewer could technique a set of ingredients and produce several radically different beverages simply by altering his processing technique. The question is then: what are you trying to accomplish, and how can you accomplish that?

Some of the evidence recovered by McGovern does help tie into the processing methods that I and others have begun to reconstruct. For example, one of the analyzed residues contained evidence of resins derived from birch and pine. I had previously speculated that wooden vessels were likely used as both mash tubs and fermentation vessels – they may have even been used to store finished product for a time. I’ve speculated that a birch and fir vessel may have been used to ferment some part of this product – an excellent avenue for dissolving tree resins. Merryn Dineley has worked on reconstructing mash houses using wooden troughs or vats and hot stones – depending on the wood, the hot water will extract various resins with great efficiency. Either of those methods could account for the presence of the tree resins in McGovern’s findings.

The evidence regarding the presence of grape sugars is also particularly interesting, as it constitutes the earliest evidence of the fermentation of the grape in northern Europe to date. It shows that ancient cultures were trying to – and able to – get their hands on the grape for a long long time. It’s most likely that grapes were still comparatively rare in Denmark and farther north – so their inclusion likely represents a person of wealth and status. It also helps reinforce the cultural parity between these ancient strong drinks and wines – occupying the same cultural purpose, it makes sense that they would perhaps share ingredients when possible.

So I’m excited! Largely because dammit I was right. It’s always good to get solid evidence confirming a speculative hypothesis.

Next up: reconstructing artifacts to pin down the processing method.

Cooking with Njall: Salt Burning, Take Two

A while back, I discussed a failed experiment in Viking-era salt production. The idea was to burn some Icelandic kelp, and use the residue as a “salt” of a sort. It didn’t really seem to do anything, and so I moved on.

But I’ve never been the type to just leave something alone. I’m a scientist, after all – I can’t accept that something is a bad idea until I’ve done it at least 5 times.

Rigor is very important.

I’ve had the remnants of my experiment kicking around in a Mason jar for a while now, so I figured what the hell – let’s give this another go. Refine the technique and try something new.

Salt Experiment Redux 1

I promise I am not making explosives.

We were recently down in North Carolina visiting some of my fiancee’s friends (fellow SCA types), and Solvarr gave me a fantastic idea: do a water extraction of the charred crap, and boil that.

In the picture above, I’ve mixed 50 g of charred kelp with 100 g of water, and allowed it to steep for ~30 minutes. The idea is to attempt to extract the salts from the solid phase, separate the liquid, and boil it down to solids.

This seems like something that may have plausibly been done in the Viking era, albeit with fairly different equipment. Recall the various bits of language revolving around “salt” in Old Norse: salt-brenna (“salt-burning”), salt-fjara (“salt-beach”), and salt-ketill (“salt-kettle”). We also see words referring to two different colors of salt: hvíta-salt (“white salt”) and svarta-salt (“black salt”).

The “salt-ketill” was something I hadn’t explored before, but it makes some sense. Ash or char the kelp in a kettle (potash anyone?), mix it with water, strain out the solids (maybe with an open-weave cloth of some kind), and boil the hell out of it. Pliny makes mention of boiling seawater, and this technique is also alluded to later by Olaus Magnus, so there seems to be precedent for the generation of salt by boiling water. Adding kelp ashes would effectively increase the solute concentration, which would in turn improve yield (making better use of precious fuel).

A relatively recent excavation of a Viking-age house in Iceland (paper courtesy of Hrefna) shows an area of high salt concentration in the house. The authors suggest it to be an area used to store kelp ash – they suggest for wool dying, but of course, they could have other uses. It does show that Vikings may have generated and stored ashed and/or charred sea plants for various uses – so mixing some with water to boil into salt seems completely feasible.

Salt Experiment Redux 2

Continuing the fine tradition of putting weird things in my mouth.

After steeping, I strained the stuff through a coffee filter and squeezed the crap out of it. All in all, it generated 42 grams of the above-pictured black liquid. I lack proper volumetric measuring equipment, so I can’t effectively estimate the density of the liquid. No matter – I’m going to boil the crap away and weigh the solids. Into the pan it went, and onto the stove:

Salt Experiment Redux 3

I’m pretty sure I belong on a watch list somewhere.
Still not making explosives.

Holy crap, it worked! I got…stuff! Stuck to my pan! My fancy copper-core frying pan that cost more than I’d like to admit!

Note to self: in the future, use a cheaper pan.

This process didn’t smell nearly as badly as the initial charring experiment did. There was something of an off odor, but that was mostly due to dirty electric stove coils – though there was a hint of kelp in the air.

I scraped the solid crap into a bowl for display purposes. It was a mostly-dry salt, with a bit of residual moisture (think fleur de sel or other hand-harvested sea salt) and a variety of colors. There was some fine grey ash mixed in as well, indicating a fairly complete combustion. We likely did completely combust the kelp during the charring – we just couldn’t separate the ash from the remnant matrix.

Salt Experiment Redux 4

Right? Almost like I planned for this to happen.

After all was said and done, I had ~5 grams of that stuff up above left. So from 150 grams (50 grams kelp/100 grams water) to 42 grams liquid to 5 grams solid. Given that the kelp meal itself is 10% salt by weight, this seems like a pretty efficient extraction method! 50 grams go in, 5 grams come out. Not too shabby, doubly considering the small quantities in use.

As is tradition, the ultimate test lay in putting that shit in my mouth.

My friends, I made salt.

There’s a hint of kelp and something burned, but no real grit. Fairly crystalline texture and appearance. Very salty. Complex tasting, too – like an interesting sea salt. No funky aroma – just a hint of burnt nothingness.

It worked. Kelp ashes + water + fire = salt.

This is not the only method I tried tonight: I also attempted a different manner of direct-fire burning. I’d bought some metal mesh screen material, and this time tried building a fire underneath the charred kelp, figuring that increased oxygen flow would do the trick.


Salt Experiment Redux 5

Also not making drugs. Or explosives.
Or salt.

I tried several configurations (the tin can there was used as a chimney starter and to try to contain the heat), but to no avail. I got the damn stuff glowing like charcoal, gave it lots of oxygen, stirred it around, left it alone, dumped lighter fluid on it – nothing.

Charred kelp meal is evidently the most flame-retardant substance known to man.

This is probably a byproduct of the configuration of the kelp – it just will not conduct oxygen and heat in such a way as to promote combustion. I’m sure that sheet kelp would actually combust like fuel – but they may very well have still mixed the ashes with water to produce the salt, as that is a good way to separate the gritty crap from the useful salt.

So my proposed method for salt production involves:

1) Charring or ashing kelp

2) Mixing that product with water

3) Separating the solids

4) Boiling the remaining liquid until only a residue remains

I have yet to experiment with actually using the stuff like salt – but at least now I have a process that will allow me to get rid of my remaining 50 pounds of kelp meal!

Future experiments will involves meat curing and fish salting using this product, to see what properties it would impart on the food. Salt is, after all, fairly fundamental in food chemistry, and the exact type of salt used can radically alter a product.

Different kettle materials can also affect the product. Iron pots, for example, will leach iron into the final salt – affecting the chemistry and flavor of any food made with it, and the diet of those who ate it.


Of course, this all assumes that they were even using salt for food preservation. A redditor from the Faroe islands posted some pictures of traditional Faroese fermented lamb (skerpikjøt, which literally means “sharp meat”) over in /r/meat:

Fuck it, you win.

They slaughter the lambs in October, hang them up in a shed for a couple of months, and then eat them. Mind you, the average temperature in the Faroes at this time ranges from 4 – 8 C, so the whole place is basically a giant refrigerator. No salt, just the breeze from the North Sea blowing through the shed constantly. Air-dried and mold-covered. And they eat the stuff raw, like prosciutto but with more microbial action. It also has a very very strong gamey flavor.

My ancestors ate some weird shit, man.

Hell, they still do.

So that’s what’s in store for this series: weird-ass foods, which will eventually be coupled with weird-ass beers.

You know you love it.

Brewing with Egil: Holy Hell, It Doesn’t Suck! (Or: Crossing the Streams)

Last time, I talked at length about my latest failure in reproducing Viking-era ale: concentrated essence of vodka-soaked hot dogs.

Can you taste it yet? Can you imagine the cornucopia of flavor in your mouth? The delicious salty smokey flavor of highly-processed extruded meat product, coupled with the mouth-puckering taste of soured honey water, wrapped in the delicate aroma of a half-digested lunch?

My friends, science is dangerous. It removes that part of the brain where “common sense” usually resides, and causes us to put unwise things in our mouths.


But today is not a day for unwise mouths. Today is a day of triumph! The hot dog wars are won! And I’m going to tell you about it!

It’s funny every damn time.

So my latest attempt at making this stuff saw a revisit of my approach. After considerable additional research and discussion with various people, I envisioned a two-part production system for Viking boozemahol: part one involves producing an iteration of a non-alcoholically fermented nutritive/medicinal grain beverage, and then using that product to start a larger quantity of sweet liquor.

I added oil seeds back to a dried malt biscuit (made using peat malt) at a rate of 1:1 by volume, to mimic the ratios documented in the Talmudic description of “zythum” (1/3 grain, 1/3 oil seed, 1/3 “salt” or probably “brine”). The biscuit was already salted, so it was a matter of tossing in some oil seeds. I used a 1:4 biscuit/seed mix (1/2 cup crushed biscuit and 1/2 cup flax seeds), mixed into a quart of water and heated slowly on the stove. The product allowed to cool, and then poured into a Mason jar. Add yeast and wait a while (about a week), then strain the liquid out.

The nutritive beverage essentially serves as a yeast production medium, allowing the yeast to multiply without actually producing significant alcohol. They also digest the grains and assist in extracting oil from oil seeds in the process, creating a sort of nutritive “liquid bread” that could also be used as a medicine. This actually makes a lot of sense; yeast require unsaturated fatty acids (read: plant-derived oil) during growth to synthesize their cell walls, and some nerds have run experiments confirming that, indeed, adding oil to a yeast starter greatly promotes yeast growth – more than even oxygenation.

The experiment above was an interesting one: the filtered liquid had the consistency of oil, was slightly carbonated, had no discernible alcohol (despite having gone for a week), and tasted fucking awful and smelled even worse.

Imagine vomit plus slightly rotting grain and a vague hint of olives. Then put it in your mouth.

That, my friends, is science.

Those who have been following along for a while may remember that my initial research already pointed me at this conclusion – that is, two different production streams for grain beverages in the ancient world: an unfermented or lightly fermented medicinal/nutritive beverage, and a strong alcoholic drink. I had previously thought those two streams were separate, but shared common ingredients. This latest production method essentially involves crossing the two streams at the exudate of the medicinal beverage.

“When someone asks you to cross the streams, you say ‘Back off man, I’m a scientist!'”
I believe this constitutes the greatest density of social currency ever dropped in one place.

In other words, the processing method for making this medicinal beverage would also produce useful byproducts that could be employed for producing other things. Recall that Pliny describes a use for Egyptian “zythum” (or rather, its “spuma”) as a cosmetic applied to the face. Given the oil content of the product I produced, I can see this being rather plausible. Vegetable fats plus vitamins from growing yeast would likely make an excellent facial moisturizer or similar skin treatment. My previous post also discussed my reasoning for seeing this as a precursor to an alcoholic beverage; Anglo-Saxon vocabularies and leechdoms indicate that “gruit” might mean something like “dregs,” both “zythum” and “beor” carry warnings against consumption by pregnant women (indicating that common ingredients may exist in both), and the 14th century Le Ménagier De Paris mentions using “leveçon de cervoise” to start an alcoholic drink.

With all that in mind, I tried it out. I mean, the big question is: does it work?

BwE - The Jug of Stuff BwE - Things In and Around My Mouth

I had ~400 ml of weird oil stuff from the above experiment. I mixed that with 1.6 L of honey-water (which itself was concocted from 320 mL of honey and 1280 mL of water), and have been letting it do its thing for about 5 days now. I literally tasted it an hour ago, and it’s awesome. It’s light, pleasant-to-drink, slightly carbonated, somewhat alcoholic, and has a nice balancing character that I can only presume is added by the medicinal compound. Oddly enough, it smells something like salted olives (which isn’t too surprising, given that it contains both salt and unsaturated vegetable fat); there’s no olive flavor, though there is definitely a savory component that is balancing the sweetness one would normally encounter in such a beverage.

I omitted fruit this time around (so as to not have too many flavors mucking things up), but plums or polar berries would go quite well in this beverage.

And so, I am pleased to report tentative success! We’ll see how this product develops as it continues to age – though I suspect that it would’ve been drunk relatively early on in the Viking era.


Restating the Process

I’ve been told by some that navigating this work is an onerous task, and trust me – it ain’t that easy for me either. So I’m going to attempt a written recap with links to my evidence/prior work; down the road, I hope to construct a sort of “roadmap” that diagrams all the connections between my various findings and pieces of evidence, to help people (including me!) navigate the murky waters of speculation.

I. Medicinal/nutritive grain beverage (MNGB):

Both Pliny and the Talmud discuss the product called “zythum,” which is described as a combination of grain, oil seeds and/or herbs (unclear from the text), and salt or brine; a medicinal use is indicated. Pliny discusses it in conjunction with other grain products (one of which is “cerevisa”), and outside of the context of alcohol. He indicates a similar use for all of the products. Pliny also discusses numerous other remedies derived from barley, and discusses the grain/herb/salt/oil seed compound “polenta” and its uses as a nourishment/medicine.

The Anglo-Saxon vocabularies compiled from the 9th to 12th centuries indicate that the word “eala” is cognate with “cerevisa,” which is one of the grain beverages also discussed by Pliny in his mention of “zythum.” He indicates similar uses between the various products, which I say serves to demonstrate possible similarities between the products. The AngloSaxon leechdoms indicate several medicinal preparations, many of which make use of “eala/ealu/ealo,” all of which are synonymous.

Thus, I conclude a degree of continuity between “zythum,” “cerevisa,” and “eala.” All three appear likely to be forms of a nutritional/medicinal grain drink. The probable ingredients for the nutritional/medicinal grain beverage are grain, oil seeds, salt, and possibly herbs. Pliny’s mention of “spuma” likely indicates that yeast were a factor in the drink, though it was probably not an alcoholic beverage.

Archaeological evidence shows that Vikings had small unleavened “breads” consisting of grains, oil seeds, and local herbs.

II. Strong (likely alcoholic) drink

Beór is seen in the vocabularies as being cognate with “hydromel” or “mulsum.” The leechdoms indicate that pregnant women should avoid drinking it, or else they will give birth prematurely. This is listed separately from precautions against drunkeness, indicating that beór is special in some regard. “Zythum” carries a similar warning, despite being glossed with a different drink (“cerevisa”); it is plausible that the two drinks share some kind of linkage.

Beór is glossed differently than eala, and the two are listed as separate options for certain preparations in the leechdoms. This indicates that beór and eala are separate products with different considerations. In some rare cases, the two appear connected by the gloss “sicera,” indicating that while they are separate products, they are probably related in some capacity. Beór is the etymological root of the modern word “beer.” It appears repeatedly in Anglo-Saxon literature, and is defined in Bosworth-Toller as “strong drink.” This gives it a separate context of use from “cerevisa,” primarily associated with celebrations.

It appears that beór is different from, but related to, “cerevisa” and consequently “zythum.”

The poem “Alvissmal” seems to indicate a relationship between the Norse “ol” and the Anglo-Saxon “beor.” In the literature, “ol” is similarly associated with celebrations.

III. Using “gruit” from MNGB to make a strong drink

Bosworth-Toller indicates that “grut” is a remnant of another product: “condimentum cerevisae.” It also means “fine meal,” and is glossed accordingly (with “pollis” in the vocabularies). “Grut” is the etymological root of “gruit,” commonly understood today to indicate a mixture of herbs used for flavoring beer.

In the Treatise of Walter de Bibbesworth, we find a word glossed with “grout” that is meant to be of wheat or barley, used in conjunction with malt to produce an alcohol. This falls in line with the meaning of “grut” as “fine meal,” and also indicates its use (somehow) in fermentation.

The 14th century Le Menagier de Paris talks about leveçon de cervoise used to start an alcoholic beverage.

My conclusion is that “gruit” was likely a grain byproduct that remained after the fermentation of some other beverage. The leavings or some other exudate would be used to produce an alcohol. Given that the word occurs in conjunction with words related to “cerevisa” quite frequently, I speculate that “gruit” is derived from “cerevisa” and/or “zythum.” This would mean that “gruit” also contains herbs and residual oils from the oil seeds in the product; the herbal connection is supported by inclusion of “gruit” in the leechdoms, and further serves to explain how “gruit” came to be associated with a purely herbal product later on.

Given that “beor” and “zythum” carry similar pregnancy restrictions, it seems plausible that one is used to make the other. More than likely, the initial medicinal product is filtered and used for its purposes, and the remaining dregs are used as a starter for an alcoholic beverage. “Zythum” uses safflower oil, and the Viking-era finds have flax seeds; both can be abortiofacients in sufficient quantity, so there seems to be an element of truth to that.

The use of a “starter” beverage to make a “strong” beverage is reflected throughout history and the modern era.

Likely, a specialized vessel was used for preparing the medicinal beverage, as I previously speculated. The strong drink could be derived from honey, fruit, malt sugars, or any combination thereof. Merryn Dineley is researching the equipment Vikings may have used to convert grain starches to sugars.


So there we have it, I think. A precursor medicinal/nutritive product leaves behind dregs that can be used to make alcohol. The medicinal product was probably manufactured in a specialized vessel containing a persistent yeast strain – the yeast would absorb into the wood, allowing the leavings (or perhaps top-cropped yeast) to be used to make alcohol. This would be a very efficient system of production, and would also likely fall to a few specialized people.

My most recent experiment uses the whole product – whether or not this was done is unknown. Future experiments will utilize only the dregs to attempt a fermentation.

Alright, that’s enough for tonight. Digest! Read! Drink! Be merry! Go forth and appreciate that you can just buy a goddamn beer instead of having to write a paper detailing its production.

And I know you probably think I don’t have to write a paper about beer to have beer – but then again, you’re probably a normal, reasonable person.

I’m a scientist. We don’t do things the easy way.