7–9 minutos
Kveik, the miracle yeast of high temperature and rapid fermentation
Two of the biggest problems for homebrewers are time and temperature.
More specifically, the time it takes per batch for the beer to ferment; and control the fermentation temperature during this time. This can be especially distressing for beginning brewers – after all, few want to wait four weeks to taste their creation – and even more so when starting out, investing in the space and cost required for a temperature-controlled fermentation chamber is unlikely.
Meet kveik: an ancient and modern yeast whose unique characteristics reduce these major obstacles to fermentation. Originating in Norway, kveik and its super-fast, super-clean, super-hot brewing strains are becoming popular among homebrewers and professional brewers around the world.
Why kveik is unique
If a homegrown mad scientist could engineer a special yeast in a lab, it might just be kveik. Genetically different from typical brewer’s yeast (saccharomyces cerevisiae),
kveik is like Frankenstein’s monster for fermentation, seemingly built from the best parts of other yeast strains.
It has all the alcohol and heat tolerance of a Belgian yeast, without any of the off flavors; the slightly fruity ester profile of American Ale yeast, with a clean finish; plus a fermentation speed that brewers only dream of and have probably never seen before.
“The fastest successful fermentation I’ve had [with kveik] was approximately 48 hours,” says homebrewer Chris Hunter, an active member of the Brewing with Kveik Facebook group.
Fermentation speeds like this mean it’s possible to go from wort to beer glass in less than 10 days. Compare that to an average of 20 days before most homebrews are ready to drink, and it’s easy to see kveik’s appeal.
At the same time, speed does not mean compromising quality. James Sheehan of homebrew club Yeast Side DC says his kveik beer was ready to drink in less than a week.
“I brewed it on Thursday and was drinking the beer on Sunday,” he says.
“With that being said, I’m typically not pushing speed to push. Kveik beers are good and very drinkable straight away, but improve after another week or two of conditioning.”
Flavors and uses of Kveik
Although kveik does not produce the smoky, spicy, or solvent flavors typically associated with alcohols and phenols that occur at high fermentation temperatures, it still has a distinct flavor profile.
Most kveik varieties are described as fruity, with orange being the most mentioned.
This flavor profile lends itself perfectly to the ever-popular NEIPA, as well as other styles typically made with American brewer’s yeast and citrus hops. Sheehan has made a wide variety of styles using kveik strains, including hoppy styles and classic styles such as cream ale, bière de garde and altbier. The bière de garde was “on the darker side, malty, lacking phenols but with some moderate fruity esters that were very good,” he says.
Carrie Soom, secretary of New York-based homebrew club The Brewminaries, believes kveik even works for tropical beers. Soom says: “I made a chocolate orange beer with Voss kveik that was delicious.
” She has also used kveik for IPAs, Blonde Ales and Kettle Sours.
Another strain of kveik, called Oslo, has been described by commercial distributors as having a clean, lager-like fermentation profile. Many homebrewers note that although Oslo has the subtler characteristics of kveik fruit, the flavor is a touch too pungent to convincingly replicate a beer.
Along with lager, styles that don’t go well with kveik include those that require spicy phenols—the distinctive clove flavor of German wheat beers and the peppery zing that denotes a season, for example, require their own specific yeast strains.
More benefits of kveik
Another factor that speeds up the fermentation process with kveik is that very little cooling of the wort is required. Kveik ferments at around 85 to 100 degrees Fahrenheit, with some homebrewers reporting successful fermentation up to 109 degrees.
(Soom, for example, says, “I usually angle it about 90 degrees and just let it rip!”). High-temperature fermentation eliminates the need for ice (usually pounds) and the cooling time of fresh wort – making the journey from boiling to below 70 degrees before pitching much quicker.
As Sheehan points out, this warm-brewing yeast also saves water and about $50 on a wort chiller, making homebrewing much more affordable and sustainable.
Another benefit of such high fermentation temperatures is that yeast cells can maintain the proper temperature simply by the heat given off by their own metabolic activities.
This means there is no need for special cooling or heating equipment for fermentation, nor finding the coolest possible spot in the house for fermentation – essentially, you can place the fermenter anywhere it will fit, and the wort will ferment without any noticeable off flavors. .
The only time the temperature might need special attention is in the winter months – Soom, for example, says he can put a hoodie over his fermenter to insulate it a bit. Hunter, who posts regularly in the kveik Facebook group, says he ferments in an outdoor barn where temperatures can drop below 30 degrees, and a simple heating pad and a sweatshirt around his fermenter are enough to keep the wort warm. under conditions favorable to kveik.
Setting up kveik for success
Kveik is largely self-sufficient. While the kveik can take care of itself most of the time, there are a few things homebrewers can do to prepare the yeast for the most successful fermentation. Due to its very high activity rate, kveik works better with more yeast nutrients than a typical saccharomyces cerevisiae.
“I suggest that [beginning brewers] double the amount of yeast nutrients required by nutrient manufacturers,” says Drew Jackson, who has been homebrewing for more than a decade.
Pitch rates are another element to consider: brewers in kveik’s homeland of Norway have traditionally pitched at very low cell counts, or what brewers call “under pitching.”
” However, Hunter advises that brewers not be severely under-toned for their first kveik brews.
“Pouring less than normal rates is fine, but if you are going to do it, be sure to aerate your wort and add nutrients to avoid stagnation or off flavors,” he says.
Finally, kveik does best in high-gravity worts, or those that have a lot of fermentable sugar and end up with more than 5% alcohol.
“Kveik really thrives on high-gravity beers,” says Soom, who admits that his only kveik “failure” was with a batch that had a lower original gravity.
“I might not have been very happy fermenting a 4% mead, even with all the yeast nutrient I gave it.” (She ended up adding American brewer’s yeast to finish off the ferment.)
Session Ales will end up very dry and with a thin, watery body due to the speed and efficiency of attenuation (the conversion of sugars to alcohol and carbon dioxide through fermentation). For example, Sheehan says, “a cream ale that I wanted to be 5% ended up being more like 6.5%.
” Because of the over-attenuation, the cream ale was unexpectedly dry and had more of an alcoholic punch.
The keys to success when using fast fermentation kveik are extra nutrients, not too low pitch rates, and a high gravity wort to start with.
With these tips, kveik fermentation will be a success.
For those ready to refine their kveik techniques, Lars Marius Garshol’s blog is a prominent source of information about the kveik used by many homebrewers.
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