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.
Hm. Probably not.
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.
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?
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.
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:
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?