Kveik Yeast

                                                                                                                                                                  by Mike Retzlaff

There is a lot of chatter today over the use of kveik (kuh-vike) yeast.  It’s a very old domesticated brewing yeast from Norway which has burst upon the modern brewing scene.

Modern brewing, commercial and otherwise, utilizes methods to carefully isolate their yeast strains for specific flavor profiles.  Most have settled in on certain temperature ranges for ales and lagers to produce traditional flavors and aromas.  Historically, brewing with kveik relies upon a decidedly different fermentation process. Before modern systems for yeast harvesting and maintenance, brewers would use yeast logs, wooden rings, bottles, and linen cloth to grow the cultures.  Of course, the preference was fresh yeast but when their supply started growing mold, they would borrow some from a nearby brewer.  That brewer might be next door, in the next town, or in the next valley.  The yeast cultures might vary wildly so it is almost certain that kveik yeasts contained a blend of strains because of being sourced from so many brewers and mixed together.  Some commercial brewers who use kveik yeast strains have changed with the times, but there are still traditional brewers who have not.

Lars Garshol is a Norwegian software engineer who’s spent a number of years researching farmhouse brewing techniques and traditions in Scandinavia.  Fortunately for the rest of us, guys like him dedicate their spare time to keep these “lost arts” from actually evaporating from society’s collective memory.  Kveik yeast is an integral part of Norwegian brewing and is making a comeback.

Kveik has proved itself to be extremely resilient as a yeast.  The various strains of this yeast seem to be happy at 90o+F and to max out at 110oF.  Most strains are good up to about 15% alcohol which makes them quite different from most of our normal brewing yeasts.  Under these extreme conditions is where kveik yeast seems to flourish.  At 104o F, most ferments will attenuate in 2 days.  At 86o F, 3 – 4 days.

Depending upon ferment temperature, kveik can produce a variety of flavors. At the higher temps, it produces the “fruit bombs” associated with the NEIPA style so prevalent these days.  They also produce very good results at normal ferment temperatures.

Kveik is quickly filling a void and taking its place as a brewing mainstay. It is returning a lot of focus back to fermentation. Simon Burhoe of Mast Landing Brewing Co. of Maine is quoted as saying “these yeasts have a lot more to offer the brewing community than just being quick fermenting, fruit bombs.”

The premier source for liquid kveik yeast is Omega Yeast Labs of Chicago, Il.  A dry version of kveik is produced by Lallemand of Canada with numerous production labs about the planet.  Most of what I hear, involves kveik being used with pressurized fermentation.  This certainly isn’t a traditional farmhouse technique and I really don’t know if it affects this yeast in a negative fashion to negate its viability for harvesting. I suppose time will tell.

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