Brewing with Egil: I Wanna Rock! (Or Two)

Well, life exploded a fair bit not too long ago, and I’m still slowly re-forming. I’ll facilitate this process by keeping the snarky, rambling, ego-stroking pontificating to a mini…

Ah, who the hell am I kidding? Read on…if you’ve got the stones.

GET IT?

Hm. Probably not.

Behold My Stones

I was going to fill this post with Twisted Sister lyrics – but my fire is faded and I can’t feel it no more. Instead, have some awful puns.

In my never-ending quest to more accurately reproduce a speculative Viking-era ale, it became “necessary” to reconstruct a Viking-era grain quern. This is the device that would be used to grind grain prior to being fashioned into “cakes” for subsequent use in beer production. I decided to make a mock-up using concrete, using an extant quern find as guidance. Volume 17 of the York Journal of Archaeology describes several quern finds. The majority are fragmentary querns from Mayen (a region in Germany) basalt, with the next largest group being gritstone (dense sandstone). Most finds lack any sort of “dressing” (grooves in the stone to aid grinding), and this seems to be common of Viking-era finds – dressed stones seem to be a post-Viking invention by and large.

I focused on find 9700, which is described on page 2628 at the above link. It’s a gritstone runner (upper) stone with a diameter of 35 cm and a thickness of 6 cm. It has a central perforation with a diameter of 7.5 cm.

I had difficulty getting a form that would give me a rock of the appropriate size, so I compromised. I cut the top off of a 5 gallon Lowe’s bucket (~12″ diameter) and used that as the form. I used Quickrete and cast a stone 30.5 cm diameter, 7.5 cm thick, with a central perforation ~4 cm in diameter. After accounting for the volume loss due to the central perforation, this wound up being pretty close to the same volume of stone as find 9700 (~5.4 L vs. ~5.5 L for the original find). Assuming that the base stone would have been approximately the same size (as seen in this Jorvik museum piece), it was cast with similar dimensions (though without quite the same amount of central perforation). In order to seat the spindle (wooden peg around which the upper stone turns) correctly, I simply jammed a length of wooden dowel about halfway into the base stone while the concrete was still wet.

There’s a joke in there, but I’m too classy to make it.

Weep Upon The Pile

This even looks kinda vulgar, if you’ve got a warped imagination.

Grain is fed into the central hole of the runner stone (that’s malted wheat in the picture above), and the handle is turned in a circular motion to grind the grain. The upper stone travels in a mostly elliptical path, pushing the grain out from the central hole into the broader surface area between the two stones.

You can see from the pile in the above picture that the upper stone sort of “floats” on a pile of grain. As the handle is turned, that pile shoots in between the two stones, which gradually grow closer together as the grain is ground down. Grind down too far, and the stones make significant contact – making your job that much harder. Of course, the increased friction between the stones seems to grind a finer flour, so it’s a constant balancing act.

That was almost clever.

There is a “rhythm” to using the stones – turning the handle while periodically feeding grain into the central hole. Once the stones are “primed” with some grain, and as long as there’s always a central pile of some sort, the upper stone turns fairly readily.

“Fairly” is a subjective term, of course. I’m still basically rubbing a 25 pound coarse rock against another 25 pound coarse rock, and that takes some effort. After about an hour and a half of grinding grain and separating coarse material, I had ~2 cups of flour and a good sweat. Quite the forearm workout.

Note: Viking women are srs bsns. Do not anger them.

So what does the flour look like?

The Ceaseless Grinding of Dust The Pitiful Rewards of Diligence

On the left, you can see both ground and unground malted wheat. The flour you see there is the result of a single pass through the stones. Not bad! Definitely some coarsely-ground material in there, but there is also quite a bit of flour.

On the right, we have some barley that I malted. That flour has been generated by grinding the grains 3 times (as in, re-grinding the product of the stones multiple times), and then bolting (sifting) the flour through a single layer of cheesecloth. As you can see, the malted barley flour has a somewhat sandy texture, but there is a good proportion of fine flour as well. Not pictured is the coarse material that was left behind after bolting – there was at least as much of that as the fine flour.

In retrospect, three passes seems unnecessary. Pass 2 and Pass 3 seemed to produce roughly the same consistency of flour, indicating that there is an upper limit to the fineness that can be generated in a mixture prior to separation of the flour. My speculation is that grain would be ground twice, bolted, and then the coarse material remaining would be fed back into the stone for another pass.

The resultant flour is also very “gritty,” as the action of grinding also loosens some grit from the concrete. I only let the stones cure for a week, which allows concrete to achieve ~60% of its final strength. Even then, concrete has similar physical properties to sandstone, which is noted by the Jorvik museum to add grit into the flour it generates. Most Viking-era quern finds are basalt, which is considerably harder; it’s conceivable that harder stone produced a less gritty flour. I’ll figure that out once I can get a line on some basalt.

My speculative brewing method involves rendering the malt into “cakes,” reflecting a malting method documented in the early Irish Senchas Már (which discusses “tests” of the malt made before it is “made into cakes”). After mucking about with the grinding stones, it seems that this was probably a necessary consequence of the method of grinding. The grain is ground much finer than we typically grind for mashing today, and excessive grinding can cause problems in conventional mashing setup by impeding the flow of wort. It’s also easier to transport and store cakes than it is to store loose grain or flour, so this really just seems to make sense.

Into the Inferno

Flatbreads or dung cakes? You know what, let’s just skip that question and sail somewhere that isn’t a frozen volcanic hell.

Even the “fine” flour seems to create a coarse bread. The bolting wasn’t as efficient as I’d have like; some husk and larger coarse bits did make it through. This is consistent with Viking-era “bread” finds, though, so I don’t think I got it “wrong.” It’s also worth noting that these breads are gritty. Like a mixture of tasty grain and sand.

What? Of course I put it in my mouth.

There is a lot of speculation that Viking toothwear patterns may have been the result of grit in their bread. After trying this out, I can see how that’s a plausible scenario. Of course, I also speculate that many breads were used for making a beverage rather than being eaten outright. Perhaps softer stones made malt cakes and harder stones made bread flour, or perhaps a Viking would eat bread until his teeth were bad enough that he’d need to drink it instead. Or maybe the toothwear comes from something else. There are many possible scenarios that can be constructed from the same evidence, so there probably wasn’t a “one true way” of doing things.

For the sake of experimentation, I went ahead and “mashed” some of the cakes to make a beer:

Drowned in Ashes A Caged Hell

I’ve revised my “beer” recipe, and I think I’m happy with it now. 1 part of crushed malt cake is mixed with 4 parts cold water. This mixture is heated slowly until it’s just shy of boiling, and then the liquid is drained off. Mixed with that is 1/2 part honey, and some fruit if so desired. In this case, I tossed in some dried juniper cones in the mash (to give a bit of a juniper flavor), and used dried cranberries as a fruit additive once everything was mixed.

My reasoning behind that is the gloss between “beor” and “hydromel.” Most “hydromel” recipes that I can find around the time are a 1:4 honey:water ratio that is fermented for a short time. Such a ratio produces a fairly sweet beverage (for the brewers, an OG around 1.095), so my goal was to replicate that sweetness. 1 part crushed biscuit contributes roughly 40% of the needed sugar content, and removes roughly half its volume via absorption. Add in the lost volume as honey (hence half a part), and you also make up the other ~60% of needed sugar. Funny how these things work out, eh?

Interestingly, all of the grit in the bread seems to have settled to the bottom during mashing and formed a thick wet layer of clay-like grain/grit material. Perhaps making the gritty bread into a liquid was also a method of “cleaning” the bread of its gritty material? The stuff pretty well stayed put as I was separating the liquid, and there was quite a bit of stone grit left behind in the pot.

In the picture on the right, you can see the result of the mixture after ~3 days of fermentation. In the mason jar is my “ealu,” revived from a previous batch using 2 small grain/flax “crackers” (remember those?) and 3 cups of water; the stuff was fermented overnight, and then some of the dregs were used to start the beer. After ~3 days of fermentation, the beer is still pretty sweet, nicely bready, a bit fruity, and somewhat alcoholic. Not bad! Exceedingly pleasant!

So what next? I’ve been poking around at my recipe and production method in light of Dr. Pat McGovern’s grog paper; in particular, the heat-treated tree resin finds imply to me a processing method that involves localized high-intensity heat being applied to a solution containing suspended tree resins. He suggests a birch syrup production method, but I find that unlikely given the lack of evidence to support such a thing. I’m working on a method inspired by Finnish sahti brewing that turns the kuurna (hollowed-out log bedded with juniper branches) into a mash tun that is heated by hot rocks. Hypothetically, one could bed a hollowed-out log with evergreen branches, fill it with water and malt cakes, and plop in hot rocks until the temperature is right. The rocks may provide sufficiently intense localized heat to produce heat-treated tree resins. Let it cool, run the liquid into a vessel where you add honey and fruit, toss in some dregs from your magic bucket, and wait a few days.

That will have to wait till it warms up a bit more and this snow gets out of the way. In the meantime, I guess I’ll just sit here and play with my rocks.

What else is new?

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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.

FIRE BAD

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.

EDIT: UPDATE WITH TOXIC METALS ANALYSIS INFORMATION

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

Kelp Salt

Be: BDL
Al: BDL
V: 386.0
Cr: 491.6
Co: 180.0
Ni: 342.2
As (total): 574.2
Se: BDL
Mo: 913.8
Cd: 186.3
Sb: BDL
Hg: BDL
Ti: BDL
Pb: BDL
Th: BDL
U238: 96.01

Control Salt (Kosher Salt boiled in a pan)

Be: BDL
Al: BDL
V: BDL
Cr: 361.6
Co: BDL
Ni: 225.6
As (total): BDL
Se: BDL
Mo: BDL
Cd: BDL
Sb: BDL
Hg: BDL
Ti: BDL
Pb: 79.08
Th: BDL
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:

http://www.codexalimentarius.net/input/download/standards/17/CXS_193e.pdf

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!