The Keys to Kveik
A Norwegian yeast ring (gjærkrans) used to harvest and preserve kveik. Photo: Lars Marius Garshol.
It is so rare to find something brand old in the beer world—an ancient tradition, practice, or ingredient we never knew existed. Kveik yeast is such a discovery—an ingredient (or agent, more properly) that represents an ancient tradition and wonderfully unusual practices. I have been compiling the salient elements of these yeasts for a podcast, but I thought it was worth distilling into a short article as well. As kveik makes its way into the world, brewers and labs are systematically stripping it of its important tradition and the brewing methods that birthed and nurtured it. Craft brewers are hammering it into the shape of yet another juice-delivery system, which is fine as far as it goes, but risks slamming the door on far richer, more interesting possibilities. Let’s all be aware of what we’re dismantling before it vanishes completely.
The Basics
Kveik (e before i) is a family of yeasts used by farmhouse brewers in Western Norway. Although the brewers obviously knew about this tradition, because it existed purely as a farm product for home consumption, it remained largely hidden until a Norwegian beer fan, Lars Marius Garshol, discovered a living farmhouse brewing tradition that extended from Norway east to Russia and south to Lithuania. He has documented this tradition extensively over the years at his blog—which you should go spend some time reading when you have a chance. What makes the Norwegian brewers so interesting is the way they have preserved their ancient yeasts, repitching them over the generations and keeping their genome alive. They are a truly unusual family of yeasts, even within the context of this rich vein of brewing.
Pronunications vary by speaker, some using a “v” sound, some a “w.” In either case, there is a slight pause after the hard k, so something like kuh-vike or kuh-wike (both rhyming with “Mike”). Kveik simply means yeast and doesn’t refer to the beer made from it (which varies). Lars provides a wonderful etymology in his book:
“Kveik comes from the same root as the English ‘quick,’ in the meaning of being alive. In fact, in dialect Norwegian kveik is two different nouns. One is female, and means the yeast, while the other is male and means to breathe new life into something. It’s used of kindling a fire, and also, metaphorically, of inspiring people to work harder.”
A final note of caution. People outside Norway are increasing referring to kveik as if it’s a single strain. In fact, the house yeasts of brewers differ profoundly in the types of flavor and aroma compounds they produce (even if most have common ancestors and behave similarly). Even more important, these yeasts are usually multi-strain cultures, not lab-bred pure strains. Removing this context is one of the most violent strippings, and it’s happening at the commercial level as well, where most labs strip all but the dominant strain.
Kveik’s Nature and Type
Despite their rustic origins, the different strains of kveik are all just Saccharomyces cerevisiae—ale yeast. Of the strains Garshol documents, some did contain bacteria and one had Pichia (a different yeast), but the Saccharomyces are so vigorous they out-compete all comers. Many are surprised to learn that Brettanomyces aren’t present, but this isn’t too surprising. The yeasts are pitched immediately, ferment quickly, and the beer isn’t stored for long-aging. And then, critically, it can’t survive the storage process brewers use (more on that presently). Remarkably, of the forty samples analyzed, all contain multiple strains of yeast. some as few as two, some as many as ten. They’re usually closely related, and one or some are dominant, yet all manage to live in harmony.
Source: Garshol. Click to enlarge.
Genetically, kveik has two ancestors. Gene research has identified one that is related to strains used to make Bavarian weissbier; the other is unrelated to any other strains so far identified. Garshol speculates that the second strain must have had a single, native ancestor since it is the distinctive element uniting the kveik yeasts and separating them from all other brewing yeasts.
A number of elements make kveik distinctive. One of the most characteristic—its ability to survive drying—comes from the way Norwegians brew. I highly recommend you visit Lars’ blog or buy his book for engrossing descriptions of traipsing across Voss in Western Norway to visit brewers, because the whole brewing process is exotic. The portion we’re concerned with is the yeast. Because they made beer for their own consumption, presumably seasonally, farmers weren’t brewing all the time. They couldn’t keep wet yeast alive long enough to survive to the next batch. Instead, they harvested the yeast on objects with lots of surface areas like “logs” (the look a bit like jenga towers) or rings, as you can see Sigmund Gjernes using in this photo in a starter. The rings look like vertabrae, to which they’re explicitly likened, and during fermentation, brewers leave them in the fermenting wort, where they become encased in the barm. The brewers haul them out after fermentation and hang them up to dry until the next use. All they have to do is dip them into the wort, and voila! the process starts anew.
In addition to this quality (typically native to yeasts but often bred out of brewing yeasts), kveik yeasts have a few common characteristics.
They are tolerant of alcohol, able to make beers of 13-16% ABV.
Despite their lineage, they are POF negative, which is to say they do not produce the spicy phenolics typical of weizen and many Belgian strains.
They flocculate well and produce well-attenuated beers, though not crazy dry ones like some saison strains do.
Finally, they ferment very warm. Some strains, like Gjernes’s, are tolerant of blood temperatures. Others may survive to 109F (43C).
Expression and Commercial Strains
One of the confusing things about “kveik” is that the strains vary. When he went to visit Sigmund Gjernes, they first sat down and tasted his beer, which Garshol described as “a strong aroma of orange-peel and Christmas spice.” Yet yeast from Hornindal he described as “milky caramel, fruity, some citrus, sometimes mushroom” (which sounds like sake yeast). A sample from Stranda is “tropical fruit aroma reminiscent of banana, with some light funky notes.” Finally, an Espe example produced “warm alcohol and fruit: cognac and plums.” And that is before these yeasts have been isolated and reduced to single-strain cultures, as most commercial labs selling them have done.
As you can see from that range, the flavors and aromas will vary a lot, and are suggestive of very different beer styles. A warming, cognac-and-fruit strain seems ideal for strong Belgian ales. Orange and spice would do well in winter-season ales. Of course, the more tropical strains sound like they’d play well with hops, which is how most brewers use them. For more detail on the source cultures, check out Garshol’s Farmhouse Yeast Registry, which has tons of info on each strain. For those interested in brewing with them, Milk the Funk has a complete, updated list of the strains available from commercial yeast labs. Finally, scoot over to Mainiacal Yeast (in Maine, naturally) if you want to track down the multi-strain original versions of these yeasts. They seem to be the only lab making them available.