Kveik – Norwegian Farmhouse Yeast

 Stop me if you know this story; farm brewers ferment without access to commercial yeast, sterile culturing, or precise temperature control. Passing their strains down and sharing them, the mixed-cultures adapt to warm fermentation, creating unique flavors. Eventually, knowledge of the strains’ precise origins is forgotten. Isolated strains eventually gain popularity in both traditional and unconventional recipes brewed all over the world. Belgian saison, right? Well that same process is happening with Norwegian kveik! These idiosyncratic yeasts often prefer temperatures even warmer than saison strains and produce a wide range of unique esters and interesting aromatics, without peppery phenolics.

TRADITIONAL-ISH BREWING

Kveik translates to yeast in a local dialect; it isn’t a style of beer. The generic term for Norwegian farmhouse ales is maltøl (malt beer), which incorporates several regional substyles. For kornøl, the addition of juniper branches along with substantial alcohol and sweetness results in a resemblance (apart from yeast character) to its cousin the wider-known Finnish sahti. Stjørdalsøl features smoked malts, although kveik is no longer used to ferment the farmhouse examples.1

There are only two Norwegian beers fermented with kveik that receive any intercontinental distribution. Alu, a collaboration of By Norse, Grünerløkka Brygghus, and Voss Bryggeri plays the Grand-Marnier aromatics of the Voss strain and resinous juniper against rich maltiness and earthy smoke plus a faint herbaceous tea-like quality from bog myrtle (Myrica gale). Vossaøl from Voss Bryggeri is a recreation of the style of the same name, paler, with woody juniper, sweetness, and bare carbonation.

Through Larsblog (garshol.priv.no/blog), Lars Marius Garshol has written numerous posts on the genetic heritage of kveik, use of juniper, and profiles of farmhouse breweries in Scandinavia and the Baltic states. Lars is the spiritual successor to Odd Nordland, author of the 1969 classic Brewing and Beer Traditions in Norway.

Highlights from Lars and his blog:

Norway isn’t exactly known for warm weather; the hot fermentation is achieved by cooling the wort to 86–102 °F (30–39 °C) and allowing the exothermic fermentation of roughly 40 gallon (150 L) batches to increase the temperature by about 8 °F (4 °C) to 93–111°F (34–44 °C). Many kveik strains produce similar flavors at lower temperatures as well, so try them even if you can’t ferment that hot.2 Three of the most widely available strains (Stranda, Voss, and Hornindal) are all Saccharomyces cerevisiae, although Voss with low certainty. The fourth, Muri, is S. bayanus/pastorianus. In situ, many are mixed Saccharomyces cultures, while a few include bacteria. No mention of Brettanomyces, but S. boulardii and Candidia humilis show up elsewhere.3

Juniper pollen has thin walls, meaning it doesn’t last well enough to be picked up in pollen analysis of ancient brewing vessels. As a result, it was likely more common historically than it is given credit.

I first brewed trial kveik batches with bland unhopped wort to get an idea for the strains’ characters. Voss was fruity and bright, while the Muri developed an unexpected clean Lactobacillus tartness. The antimicrobial power of hops was missed.

I was inspired to brew something more traditional while reading The Homebrewer’s Almanac (by Scratch Brewing’s Marika Josephson, Aaron Kleidon, and Ryan Tockstein) when it hit me that the “Eastern Red Cedar” growing in my backyard was Juniperus virginiana, Virginia juniper! Brewing with foraged ingredients requires positive identification. After looking at the growing range and pictures of the foliage and bark, I contacted a local arborist to confirm the tree’s identity. For techniques and cautions, see my article “Foraging for Ingredients” (BYO September 2015).

I harvested a gallon bag of 12-inch (0.3-m) cuttings on an icy February morning before driving to Virginia to homebrew with Blane Perry, of Sinistral Brewing and Carlos Barroso of Shaka Brewing. We loosely followed the juniper schedule for Scratch Brewing’s Sahti. This protocol included juniper throughout the mash, boil, and whirlpool, which imparted a bright green, citrusy-herbal aroma. For smoke, we added Weyermann Oak Smoked Wheat Malt and Beech Smoked Barley Malt. Alder is the most common wood used by the small local maltsters of Norway (alder-smoked malt is also featured in Alaskan Brewing Co.’s Smoked Porter). After fermentation by Omega HotHeadTM at 90 °F (32 °C) the aroma was apricot gummy candy, juicy, and fruity, but with a rich savory smoke. In comparison, the Voss culture I brought back and Blane pitched into his share of the wort created a less fruity, more balanced and delicate beer.

I had shared a bottle of Alu with Nathan Zeender at Right Proper Brewing Co. My old friend (and boss) Jacob McKean from Modern Times Beer Co. was headed to Washington DC so we roped him into a collaboration. We went darker and maltier, with a couple 6-foot (1.8 m) juniper branches (which Nathan harvested with permission from the National Arboretum) infused into the 190 °F (88 °C) hot liquor tank. Nathan blended the HotHeadTM harvested from my homebrew (surprisingly trusting) with US-05, and fermented below 70 °F (21 °C) to temper the fruitiness. The resulting beer was dubbed Hyperborea (after a mythic people of the Arctic Circle). The overnight infusion of juniper branches provided cedarwood notes that stayed to the background although enlivened by less-traditional juniper berries late in the boil. The beer was delicious, combining rich maltiness, juniper-smoke woodiness, and subdued yeast fruitiness.

NEWFANGLED

Even if smoke and juniper aren’t your favorite flavors, kveik may still be useful. Homebrewers without access to temperature control often resort to saison and other phenolic Belgian strains during the summer. Their spicy flavors and high attenuation can wear thin, clashing with assertive hoppiness and walking over fruit. Conversely, the flavors of kveik can provide a fun pairing with citrusy and tropical American and Southern Hemisphere hops and actual fruit.

I brewed a vegan milkshake IPA with frozen mango, vanilla bean, and Experimental Stone Fruit hops fermented with Omega HotHeadTM. The orange notes provided by the yeast along with the vanilla created a delightful Creamsicle® flavor. Served on beer gas through a stout faucet for lactose-free creaminess.

Right Proper followed Hyperborea with Soused, a Mosaic-hopped IPA balancing fruity notes from the repitched kveik culture and resin from another juniper branch infusion. It was a collaboration with Stone Brewing, Pen Druid Brewing, and the drone metal band Sunn O))). Hoppy enough that the juniper and fermentation came through as added depth rather than being showcased. Still, one of my favorite hoppy beers they’ve brewed!