Kveik and other traditional northern European farmhouse beer yeasts help us to understand the history of beer and they are highly useful for today’s brewers. This introduction gives the necessary background information to successfully brew with these fascinating creatures. The next episodes will teach you the art of fermentation and maintaining farmhouse yeast cultures. Finally, Farmhouse Yeast Descriptions list my experices with various farmhouse yeasts. Whether you brew traditional or modern beer, this guide helps you to brew it better.
Farmhouse homebrewing used to be a common activity throughout northern Europe. Before commercial yeast, each farmhouse had own yeast that was propagated from batch to batch. The yeast culture was maintained with tried-and-true folk wisdom.
When commercial larger scale brewing emerged in the Late Middle Ages, professional brewing and farmhouse took different paths. Gradually this led to different kinds of yeast evolution that gave us two separate branches of beer yeast: modern brewer’s yeast and traditional farmhouse yeast.
The traditional farmhouse yeasts of Europe were almost lost, but in the 2010s it was discovered that some farmhouse brewers in Norway, Lithuania, Latvia, and Russia still hold on to their farmhouse yeast that has been in the family for as long as anybody remembers. Norwegian farmhouse yeast kveik is the best known, but this guide covers the Baltic yeasts too.
Luckily those farmhouse yeasts are now widely available and they appear to be highly useful for today’s brewers. However, they behave differently than modern brewer’s yeast and give the best results when the brewer knows the old farmhouse tricks. The purpose of this guide is to teach you those tricks.
This intro helps you to understand how these yeasts work. The second part gives you practical fermentation tips and the third episode teaches you to maintain yeast cultures the farmhouse way. My experiences with various farmhouse yeasts are written into the Farmhouse yeast database. All these documents are regularly updated as I learn more.
Why Another Kveik Guide?
Brewing with kveik is already fairly well documented, see for example Lars Marius Garshol’s How to use kveik, Milk The Funk Wiki, and Escarpment Labs’ Using Norwegian Kveik: Old Yeast, New Tricks. However, I believe that my long hands-on experience in brewing both traditional and modern beers brings in a new perspective. Writing three books on beer and brewing has also schooled me to write concise brewing instructions.
I have brewed with Nordic and Baltic farmhouse yeasts since 2015 and met many Norwegian farmhouse brewers. My experience comes from both original farmhouse yeast cultures and commercial versions isolated from them. I have used these yeasts for traditional farmhouse ales, modern beers, and ciders. The recommendations in this guide are largely based on my own experience.
Secondly, researchers and brewers around the world are constantly learning more about these yeasts. This guide will be updated as our understanding grows. In this guide, I’m also covering Baltic farmhouse yeasts that are still fairly unknown territory in 2020. In my opinion, covering all traditional European farmhouse yeasts in one guide eventually pays off.
Practical means that I have to leave out many fascinating details and stories. My book Viking Age Brew gives a concise background for both farmhouse brewing and yeast. For a thorough account, check Lars Marius Garshol’s book Historical Brewing Techniques. Claire Bullen’s A Fire Being Kindled – The Revolutionary Story of Kveik tells vividly how Norwegian farmhouse yeast was rediscovered.
What Is Farmhouse Yeast?
With farmhouse yeast, I mean a yeast culture that has been maintained with traditional farmhouse brewing methods to the present day. These methods have shaped their evolution and character. Likewise, with brewer’s yeast, I refer to yeasts that have adapted to the modern brewing process.
The main characteristics of farmhouse yeasts include:
- These yeasts can ferment at high temperatures (30–40°C, 86–104°F) without off-flavors.
- Usually, they ferment fast and beer can be ready to drink in less than a week.
- They are robust and alcohol tolerant.
For many, these features alone are an important reason to use farmhouse yeasts. Why the hell aren’t all brewing yeast like this? Microbiologist Richard Preiss suspects that brewing yeast used to be like this but it has lost these traits in the course of evolution. Lars Marius Garshol believes that brewers, in general, used to ferment at higher temperatures but when better cooling systems were invented, the fermentation temperature was lowered to fight lactic bacteria. When the ability to ferment fast at high temperatures became insignificant for yeast survival, the trait was lost.
These farmhouse yeasts are not miracle makers, however. Using them requires knowledge and experience just like any fermentation. Homebrew forums now boast with troubleshooting why kveik is not fermenting fast and well.
Farmhouse yeasts used to be common across Europe but gradually they have become extinct even in many areas where archaic farmhouse brewing otherwise survives. In Finland for example, sahti brewers have switched to baker’s yeast and the last of the farmhouse yeasts died out in the 1960s. Gotlandricke and koduõlu have faced the same fate.
Even in Norway, Lithuania, Latvia, and Russia where traditional farmhouse yeasts have been rediscovered, the culture remains strong only in a few specific areas. Luckily new yeasts are still found every year. For a list of knowns alive farmhouse yeasts, see Garshol’s Farmhouse Yeast Registry.
Many think of saisons when they hear farmhouse yeast. Indeed, saison yeasts can ferment at unusually warm which probably is a remnant from an old farmhouse brewing tradition. However, saison yeasts sold today have been captured from commercial breweries operated with fairly modern brewing techniques. Brewers use them more or less fairly with modern techniques that are documented extensively elsewhere. For these reasons, I’m leaving saison yeasts out from this guide. Don’t get me wrong, I love saisons and these yeasts are certainly fascinating.
What Are Traditional Farmhouse Methods?
Here’s a quick wrap-up of traditional farmhouse brewing methods that have played an important role in the evolution of farmhouse yeast:
- These are homebrews of regular farmhouse folk. The brewing heritage stems from tried-and-true folk wisdom rather than professional brewing knowledge.
- Many of farmhouse brews are so-called raw ales, made without boiling the mash or wort. Unboiled wort is rich in proteins and nutrients and it is certainly a different kind of growth media for yeast. In some areas, such as Voss in Norway, kveik has been cultured for centuries with boiled worts.
- When farmhouse brewing vessels were made of wood, cooling was difficult and yeast was pitched into very warm wort. Most farmhouse brewers using traditional yeast still ferment at 27–42°C (81–108°F).
- Traditionally stronger Nordic and Baltic farmhouse beers have been brewed only a few times a year for seasonal celebrations and feasts. This has helped to avoid brewery contaminants.
- Nordic and Baltic feast ales are very drinkable and on a sweet side. If the beer goes sour, the beer is dumped and the brewer reverts to yeast that doesn’t make beer sour.
What Does Microbiology Say About Farmhouse Yeast?
Recent microbiological studies on kveiks have revealed that:
- Kveiks have been domesticated, that is, they have properties that are useful to the brewer but not typical for wild yeasts.
- Usually, kveiks are mixtures of several Saccharomyces Cerevisiae yeast strains.
- Often these yeasts are free of bacteria – the yeasts had overthrown them. Some farmhouse yeasts include also souring bacteria, but even those are used for producing beer that is not sour.
- Kveiks do not produce clove-tasting phenols. It seems that Norwegian brewers have liked their beer without phenolic taste and the evolution has pruned away the gene responsible for this flavor.
These properties were probably typical also for a large share of brewer’s yeast before the invention of single-strain laboratory techniques. In fact, genetic studies have revealed an old kinship between kveiks and brewer’s yeast. This is a fascinating story that is well documented in Historical Brewing Techniques and Larsblog.
There are far fewer studies in on Baltic and Russian farmhouse yeasts but at least we know that they are domesticated beer yeasts that are used for non-sour beers. Some Lithuanian strains are mixtures S. Cerevisiae yeast strains while some seem to contain only one strain (see Milk The Funk on Landrace Yeast). Compared to kveik, Lithuanian strains seem to more often include Lactobacillus. Baltic and Russian generally produce phenolic flavor and this a major difference between Norwegian kveiks and other farmhouse yeasts.
In this guide, I use the term “yeast” liberally for both yeast strains and mixed yeast cultures. If there’s a need to be more specific, I speak about a yeast strain (only one strain of yeast), mixed yeast culture (several yeasts), or mixed culture (mixtures of microbes, usually yeasts and possibly souring bacteria).
What These Yeasts Are Good For?
Well, obviously for traditional farmhouse ales, but they shine in various kinds of modern beers too. For modern brewers, the exotic and unusual fermentation flavors are perhaps the primary reason to use these yeasts. Superior performance is another:
- Producing clean beer without temperature control is a plus for many. Some kveiks are very neutral in flavor, and if you just want a clean malty and/or hoppy beers kveiks can do that too.
- Producing beers quickly may not be important for everyone, but I certainly enjoy fast fermentation, prompt flocculation, and tasty beer right after that. Especially fresh malt, hop, and juniper flavors are best, well, very fresh.
- Fusel alcohols can be a nuisance in high alcohol beers like barley wines and imperial stouts but with kveik avoiding these off-flavors is easy.
Some beer experts have said that kveik will revolutionize commercial brewing because breweries can produce beer faster without expensive cooling systems. I don’t have much to say about that. I just want to have the best beer possible.
In my mind, cultural reasons for using these yeasts are important too:
- In Europe, large scale professional brewing has been mainstream for merely the last 700 years or so. Before that, virtually since the dawn of civilization, malting and brewing were typically done by regular farmhouse folk. So, to understand the history of beer, we need to understand farmhouse brewing and farmhouse yeast.
- if you are into historical brewing, farmhouse yeasts are your best bet for recreating Iron Age, Viking Age, and medieval beers.
- There’s a relatively large branch of homebrewing that could be described as alternative brewing or traditional brewing. These folks view brewing as cooking or a traditional craft, as opposed to today’s engineering-like brewing. Farmhouse yeast sounds like an obvious tool for them.
I haven’t given up on using brewer’s yeast but the majority of my beers are fermented with kveiks and Baltic farmhouse yeasts. I see also a potential for meads and ciders (more about that below).
What About the Flavors?
The flavors produced by farmhouse yeasts are wide and varied:
- Kveiks can add fruitiness that tastes special. Tropical or citrus fruits are typical descriptors. Some kveiks taste like fruity English yeast on steroids.
- Although kveiks do not produce phenolic flavors, some kveiks add flavors of Christmas spices or pepper.
- Some kveiks produce unusual umami flavors reminiscent of mushrooms.
- Some kveiks are neutral in flavor and let the other ingredients shine.
- Lithuanian yeasts often produce tropical fruit flavors but in addition, there’s a phenolic background flavor too. This may sound like Belgian but the Lithuanian yeasts that I have tested have been really unique and distinct from Belgian strains.
- One Lithuanian yeast that I tested produced caramel-candy (diacetyl) flavor that wasn’t unpleasant in a raw farmhouse ale.
I should stress that these flavors aren’t usually aggressive. Traditional farmhouse beers are brewed for drinkability.
Here’s how I have used these yeasts in contemporary brews:
- I like yeast-centered beers where the fermentation is the king. Some kveiks and Lithuanian yeasts are very good for that. Take for example your favorite saison or blond Belgian ale recipe and ferment the beer with kveik or Baltic yeast. It probably doesn’t taste like Belgian but I’m pretty sure that you’ll like beer.
- Robust malt flavor is my favorite candy. Some kveiks can really make the malt blossom.
- I have tasted plenty of kveik IPAs which weren’t great. I believe this was because of the wrong kveik and the lack of practice with kveiks. Kveik fermented hoppy beers can be great but some kveiks are much better for the job.
- Big beers with aging potential are lovely. For that, you need a robust yeast that can ferment high alcohol wort without off-flavors. Flavors that add long-term complexity are a plus. I have had good results with Sigmund’s kveik.
- Sour ales with kveik and lactic bacteria are simple to brew but the end result can be very complex: tropical fruits and pleasant tartness as if exotic fruits had been used.
- For years I have fermented my ciders with Sigmund’s kveik. I don’t kill the wild yeast. I just throw a few flakes of dried kveik into a fermenter. For more details, see section Making Ciders and Meads with Kveik in Fermentation.
Farmhouse Yeast Descriptions lists my personal opinions on matching various kveiks and Lithuanian yeasts for beer flavors.
Obtaining Farmhouse Yeasts
Commercial kveiks are now widely available throughout the world. Several yeast companies produce them and well-stocked homebrew stores usually sell them. In 2020, Baltic and Russian strains are still somewhat harder to find but even they are within an easy reach of millions of brewers. Check Milk the Funk Wiki for a list of commercially available farmhouse yeast cultures.
Homebrewers are also passing on the original non-lab cultures. They brew with the mixed culture, harvest the yeast, and then deliver either wet slurry or dried yeast. Especially dried kveik flakes are easy to send in a letter. A knowledgeable brewer can do this well but the chain from brewer to brewer can also change the yeast. For example, the yeast behavior can change from the original, or bacteria that weren’t originally there can be introduced.
I have seen kveiks sold at eBay and I find this problematic. It can work but the dried kveik flakes on sale come with little information. How are these sellers brewing their beer and how are they harvesting? Do they perform any quality checks for the cultures they are selling? Commercial yeast labs aren’t usually selling the original cultures because quality control of a non-isolated motley crew of microbes is difficult.
The Difference Between the Original and Commercial Farmhouse Yeasts
What yeast laboratories do when they receive a farmhouse yeast culture? First, they kill all the contaminants, such as souring bacteria. Then, they separate the mix into different strains. They study the properties of each strain separately. When they are producing a sellable yeast, they either choose one representative strain or make a blend of strains.
The goal of the yeast lab is to capture the essential features of the original culture but obviously, the commercial version is different. The mixture of strains might be working in symbiosis. Even the bacteria in the mix can be part of the symbiosis and partly behind the exquisite flavor, although the brewer doesn’t let the ale go sour. Because of the laboratory work, the flavor, fermentation speed, or flocculation may change. The laboratory selection also means that yeasts sold by different companies can be different, even if they started with the same original source.
On the other hand, with the commercial yeasts brewers gets a guarantee that the beer doesn’t go sour because of the yeast. The laboratory has checked that the yeast performs well and retains many of the characteristics of the original. I completely approve of the commercial farmhouse yeasts and I have tasted fabulous beers fermented with them. For those who want to go deep into farmhouse brewing traditions or the history of beer, I recommend trying the original cultures.
Traditionally maintained farmhouse yeast cultures work surprisingly well but using them is always a risk. If you can store the beer cool or consume it soon the risk is very small. If bottled or canned beer needs to sit at warm for weeks, I would be hesitant to use the original cultures.
At my home brewery, I have brewed more with the original cultures than commercial versions. When I started playing with the traditionally harvested slurries and dried kveiks, I suspected that unpredictable refermentation or sourness sneaking in after bottling might be a problem. I have never had such problems. One imperial stout fermented with the original version of Sigmund’s kveik aged beautifully in the bottle. But I store all my beers in a cool cellar.
So far the only problems with the original farmhouse yeasts have been with cultures known to contain bacteria. With these cultures, my traditional farmhouse ale has gone sour a few times. Usually the symptoms of sourness arise within a week from brewing.
Knowing Your Yeast
Before rushing into brewing, I advise you to check the background of the farmhouse yeast you are using. You don’t need to brew in the same way as the original owner of the yeast but the knowledge helps you to brew better beer.
The Farmhouse yeast registry maintained by Lars Marius is the first place to go. It probably lists at least some details about the origins of the yeast you are about to brew with. For managing fermentation, the key elements are fermentation temperature, pitching rate, does the original yeast contain bacteria, and how the original owner harvests the yeast (if you are harvesting).
Now, the actual brewing tips start from the part II of this guide, Practical Guide to Kveik and Other Farmhouse Yeast: Fermentation. Farmhouse Yeast Descriptions lists my experiences with various kveiks and Lithuanian yeasts.
May 20, 2020: Added a comment about kveik on eBay.