Yeast is the life of beer- the element that through its life cycle transforms and accents the characteristics given by those base ingredients that make up our wort- grain, water, and hops. The cultivation of yeast for use in the American craft beer scene has given rise to a large industry with an extensive library of clean brewer's yeast (and increasingly, wild yeasts) at our disposal. These cultivated strains are designed and identified for stylistic accuracy, complete with information about the yeast's properties and its potential flavor attributes.
When so much of how we use yeast is based on what is known about the particular strain, it is incredibly exciting to introduce a yeast whose properties we are still learning. Here is a new frontier, if you will, for our craft beer scene.
The term 'kveik' itself, with regards to beer, is often used to reference "homegrown" yeast in Norway, rather than industrially available yeast for brewing. With these kveik strains becoming commercially available, and more genetic testing on the organism, we are coming to learn more about the history of this unique type of yeast.
DNA sequencing shows that, while kveik yeast exhibits a remarkable genetic diversity (ranging as much as from, say, English Ale to Saison yeast), most cultures are in fact strains of Saccharomyces cerevisiae, traditional brewer's yeast. The cultures themselves are always a mix of, rather than individual, strains.
Questions then arise as to how years of this type of farmhouse cultivation, environmental factors, and potential hybridizations have affected the trajectory of the yeast's development.
Some characteristics are remarkably consistent in kveik, even across its wide diversity:
(1) Kveik is incredibly resistant to typical environmental stressors, most notably heat. (It can withstand much higher temperatures than your average brewer's yeast)
(2) Kveik has a very high ethanol (alcohol) tolerance (It will drink you under the table.)
(3) Kveik tends to produce an incredibly unique blend of earthy and estery flavor components.
So how can we harness what the Norweigans have been using for centuries to enhance the quality of our beer? There are certain elements of the yeast than make it a hardy and multifarious weapon for the modern brewer:
Kveik yeast is very biotransformative. This means that it will alter and accent the flavors already provided by the other ingredients to a great degree. A host of esters (themselves fruity and floral) will be created to give depth and intensity of flavor to the beer. This seems to be especially true with regards to its interplay with hop characteristics, which are often greatly emboldened and complemented.
The alcohol tolerance of Kveik is very useful in brewing higher gravity beers. Going hand in hand with its biotransformative properties, its ability to tolerate high gravity means we will have a great reshaping and augmenting of flavors even at those high ABVs. Think- even greater number of sweet and floral esters to add depth.
Overall, there is much to learn. Craft beer is so much about paying homage to the great brewing traditions that came before, while finding new ways to express both those methods of production and the peculiarities of life that birthed them, in each and every new brew.
Kveik is yet another of those peculiarities, with many stories to tell.