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Somewhat unexpectedly, a family of Norwegian farmhouse yeasts have burst onto the brewing scene in recent years. Kveik has not yet become a hyped fashion, but it seems almost about to. So what is kveik? And where did it come from?
Until about 150 years ago, most farmers in northern Europe brewed their own beer, from their own grain, for their own use. And all these brewers had their own yeast, because there was no alternative. Modernization killed this brewing tradition in most places, but it still survives in isolated pockets across northern Europe. And in a few places the yeast survives, too.
The yeasts that the farmers used were treated differently from the way commercial brewers have treated their yeast. Fermentation was far hotter, and shorter, and the yeast was often dried. Because of this the farmers had yeast that behaved differently from the modern commercial brewing yeasts familiar to today’s brewers. I call these yeasts „farmhouse yeasts” to distinguish them.
Over the last five years nearly fifty cultures of farmhouse yeasts have been collected from farmhouse brewers in Norway, Lithuania, Latvia, and Russia. Very likely more cultures exist, but have yet to be found.
Localities of Kveik Yeasts (Source: 3)
Efforts have been made to trace the origin of each of these cultures, and every time the chain ends within a few links with someone who is now dead. Nobody seems to know where the yeasts came from further back than a few decades, but it’s clear that they have been circulating in these brewing communities for a long time. Quite possibly a very long time indeed.
Analysis of these farmhouse yeasts shows that most of them are Saccharomyces cerevisiae, but not all. All of the cultures consist of multiple strains, but determining how many strains is not easy. To take an example, farmhouse yeast #5, from Terje Raftevold in western Norway, was analyzed by yeast labs who sell yeast commercially. They found 2 strains. The National Collection of Yeast Cultures, in Norwich, England, did a more thorough analysis and found 8 strains. De Proefbrouwerij found 17 strains. The Carlsberg Lab reportedly found 40.
A large number of farmhouse yeast cultures have been collected in western Norway, from Hardanger in the south to Sunnmøre in the north. All of these are Saccharomyces cerevisiae yeasts, and all the yeasts are more closely related to each other than to any other yeasts. In other words, they form a separate family of yeasts. It’s the members of this family we call „kveik”.
None of the farmhouse yeasts collected from Lithuania, Latvia, and Russia belong to the kveik family. Surprisingly, kveik turns out to belong to the Beer 1 family of brewing yeasts, together with most German, British, and American brewing yeasts (and some Belgian ones). However, the kveik family seems to have been formed by a hybridization event between a Beer 1 yeast and a yeast that has no known relatives. The unknown yeast may have been a wild yeast, although this is not yet known.
Kveik has several unusual properties. The most famous is its ability to ferment very hot without producing off-flavours. The Voss kveiks can ferment at up to 42–43C without ill effects. Other kveiks prefer lower temperatures, but generally 30C or above.
Kveik also stands out for the speed of fermentation. It will often show visible activity within an hour or two of being pitched, and a completely fermented wort of 6–9% in 36 hours is not at all unusual. And since kveik produces very little in the way of off-flavours, the beer is perfectly drinkable more or less right away.
All the known kveik strains can be dried, because this was the traditional way to preserve yeast in Norway. The kveiks are all non-phenolic, and non-diastatic, unlike the saison yeasts, which belong to the Beer 2 family. Norwegian farmhouse ale has historically been very strong, which is probably why the kveiks have a high alcohol tolerance of 13–16%.
The kveik family is quite diverse, so the flavours produced by individual kveiks range from orangey (Voss kveiks), banana/melon (Stranda), through mango/pineapple (Ebbegarden), to milky caramel, mushroom, and pineapple (Hornindal). There are many more variants, but in general kveik tends to be more aromatic than ordinary brewing yeast and to produce tropical fruit aromas.
The main way to control the strength of aroma production is through the pitch rate. Underpitching gives a stronger aroma, and no off flavours. Fermentation temperature also affects the aroma, but less so than the pitch rate. A good pitch rate for a beer of 6–10% is 1 billion cells per liter.
Kveik can be used for English beer styles, as well as many of the modern craft styles. It is particularly suitable for IPA and NEIPA, since the tropical aromas from the yeast fit well with those from modern craft hops, and the fast fermentation and maturation allow the beer to be released fresh. Of course, kveik can also be used for the traditional styles, such as heimabrygg and kornøl. Somewhat counter-intuitively, kveik will not produce typical saison beers, because it is neither diastatic nor phenolic.
Reusing kveik is easy: refridgerated slurry will keep 6 months without difficulties. It can be stored at least two years, but must then be propagated before use to ensure it is fresh. Farmhouse brewers usually dry it, in the oven or using gentle heat such as a shoe rack or a mushroom drier. In dried form it can be frozen and will then keep for at least two decades, possibly longer.
If reusing the original kveiks consisting of many strains some care must be taken to preserve the composition of strains, or the culture may change behaviour. The safest way to do it is to harvest the yeast in the same way as the original owner. Consult the yeast table to see how.
It’s also recommended to keep track of which cultures were harvested from which batches of beer, and to only reuse the yeast from the best batches. This is what the farmhouse brewers themselves do, and it has the effect of preventing infections from taking hold, and encouraging the culture to develop in desirable directions.
Many brewers are concerned about risking brewery infections if they use kveik, but remember that this is a Beer 1 yeast. It is neither diastatic nor phenolic. So if an „infection” were to happen, and some kveik cells get into a beer where they are not supposed to be, the effect is unlikely to be at all noticeable.
The word „kveik” is one of several Norwegian dialect words for yeast, and is the most common word for yeast in the inland districts of southern and western Norway. Etymologically it comes from the same root as the English „quick” in the sense of being alive. In Norwegian dialects it can be used to mean both breathing life into something (such as lighting a fire) and yeast. In Voss in western Norway it’s become common to refer to shop yeast as „gjær”, while the farmhouse yeast is called „kveik”.
Experiencing the brewing culture that these yeasts come out of is very difficult. Even just tasting the traditional beers is very hard, because they are not sold commercially. There is, however, one solution: Norsk Kornølfestival, a festival dedicated to traditional beers, held in Hornindal in western Norway in October. Here the farmhouse brewers serve their beers and talk about them, and some even hand out samples of the family kveik.
The use of kveik in western Norway has been in a steep decline over the past century. Many of the current cultures were collected from brewers who had stopped using them, but were still preserving them in their freezers. Younger people in these districts seem to mostly favour modern home brewing, although with the recent surge of interest in traditional beer it’s possible that this may be changing.
Outside the traditional brewing regions the use of kveik has been growing rapidly over the past five years among both home brewers and commercial brewers. At the time of writing Ratebeer.com lists 423 commercial beers brewed with kveik, but the list is not complete. A number of commercial labs now sell kveik, such as White Labs, Imperial Yeast, Omega Yeast, the Yeast Bay, Fermentuum Mobile, and Escarpment Labs. In addition, many enthusiasts share different kveik (and other farmhouse) cultures with each other through online forums.
Research on kveik and the other farmhouse yeasts is still ongoing. Work is under way to learn more about the origin and behaviour of the non-kveik farmhouse yeasts. Work is also ongoing to study the brewing properties of kveik in more detail.
Two farmhouse yeast cultures have been collected from eastern Norway, which is geographically divided from western Norway, and therefore had a different brewing tradition. Nothing is known about what kind of yeast farmhouse brewers in eastern Norway used, but it is hoped that these two cultures can give us an answer, as they come from distinct regions: Hallingdal and Telemark.
The book will be released soon at Brewers Publications
What future looks like for kveik is difficult to judge at the moment. The collected cultures have been deposited with the National Collection of Yeast Cultures in the UK, and also many other yeast labs, so the yeast itself should be guaranteed survival. The brewing traditions in western Norway were on the decline, but it is possible that the increased interest both in Norway and abroad may reverse the decline.
In commercial brewing kveik seems to be headed for a hype peak, and the question is what lies on the other side of the peak. Many hyped trends peak and disappear, but my prediction is that in this case the yeast itself is such a useful tool for brewers that even after the excitement dies down commercial brewers will continue to use the yeast, simply because it produces good and unique beers in a highly cost-effective way.
References:
- Preiss et al, 2018. „Traditional Norwegian Kveik are a Genetically Distinct Group of Domesticated Saccharomyces cerevisiae Brewing Yeasts.” In Frontiers in Microbiology, Evolutionary and Genomic Microbiology, 12 September 2018. doi.org/10.3389/fmicb.2018.02137
- Garshol & Preiss. 2018. „How to Brew with Kveik.” MBAA TQ vol. 55, no. 4, p 76–83.
- Yeast registry: http://www.garshol.priv.no/download/farmhouse/kveik.html
All Photos by Lars Garshol. The product images are from the web-Sites of the producers.