How to use Kveik Yeast

Kveik was brought to the wider brewing world’s attention by Lars Marius Garshol. At the time it was only available from the farms where it had been cultivated, and Garshol travelled from farm to farm sampling different beers fermented with these yeasts and recording the brewing processes which had remained part of that tradition for generations.

The industrial revolution passed a lot of these brewing traditions by and these farmhouse brewers would use yeast in much of the same way previous generations would: simply throwing yeast slurry into wort and collecting it during or after fermentation.

Of course these farmhouse brewers didn’t have microbiology equipment to check their yeast and some very unique types of beer yeast (saccharomyces cerevisiae) developed. Often they would contain more than one strain of S. cerevisiae creating a unique fermentation character.

It didn’t take long for labs to get hold of and sell commercial versions of these kveik yeasts, however labs take single strain isolates from the farmhouse blends. Whilst the isolates have their own character, the farmhouse blends have an unmatched depth of flavour.

Unlike regular brewer’s yeast, kveik can ferment really warm, some up to 40C and will ferment a beer in as little as 3 days! It’s possible to pitch and ferment regular yeast at this temperature and it will ferment really quickly, but it will throw out a ton of off flavours and the beer will be awful. Kveik is far more stable and doesn’t create off flavours at high temperatures.

There is a bit of a catch, the wort needs to be high gravity otherwise there won’t be enough nutrients for a healthy fermentation. Kveik needs added nutrients for regular and lower gravity beers otherwise the ferment will be a long one! S. cerevisiae is cannibalistic so a few tablespoons of dried bread yeast thrown into the boil will be enough nutrients

This is because of how Norwegian farmhouse beers are made. They tend to be quite high gravity (>1.070) and for generations the yeast was thrown in whilst the wort was still cooling down, at around 30C+. This is because it’s a bad idea to keep a large vat of sugary liquid sitting around for long otherwise it goes bad, and the brewers didn’t want to stand around waiting for the wort to cool.

Over time, this created a selective breeding process for yeast. The batches that went bad were thrown out, and those that were good had the yeast reused from that batch. So specialist yeast was developed which liked high gravity and warm temperatures.

In Norway today there are still farmhouses which make beer in this way, with some still even making their own malt!

Kvieks have different flavours ranging from orange and marmalade to plums and apricots to tropical sour beers. Different varieties can be used for different styles, with Voss being suitable for ales and IPAs, Espe for stouts and brown ales, and Ebbegarden for sours. Many (myself included) have even made very good pseudo lagers with Skare, which fermented cooler has a nice clean and crisp malt forward profile.

What does this mean for the homebrewer? To get the most out of kveik it needs to be treated in a specific way. Don’t worry, it’s not very different from regular yeast, but doing a couple of things differently will result in a fast and healthy ferment.

Store the dried yeast in the freezer. Kveik has slightly different properties to regular yeast which mean it can be frozen and stored for a long time, unlike regular yeast.

It requires a small pitch rate. One sachet is enough to ferment 20-25 litres of wort. This is the equivalent of one teaspoon of slurry. It seems almost criminal to underpitch this much, but the yeast actually prefers this and will produce more esters this way.

If the yeast has been sitting in a freezer for a long time it would be a good idea to make a starter first. Use 50g of DME and 500ml of water, boil to sterilise and place in a sanitised container. Once cool add the flakes and stir. In a few days it will be ready to pitch. Alternatively take 500ml of the first runnings, wait for it to cool to pitching temperature and pitch the flakes. Just remember to be extra careful with sanitisation when dealing with yeast. Cover containers with foil and if in doubt, spray with Chemsan.

In a 20-25 litre batch, I use three tablespoons of bread yeast added 10-15 minutes before the end of the boil. This is enough nutrient for the kveik to have a fast and healthy fermentation

Temperature is strain dependent, Lars Marius Garshol has an amazing blog with more information about the maximum fermentation temperature for each variety. At the higher end of the temperature range the beer will ferment quicker with more yeast character, and slower and cleaner at the lower end. Some strains aren’t clean and will produce esters at any temperature, but they will be more subdued.

The video above has more information on using kveik. Do let us know how you got on with your kveik beers!