is that the kveik yeast across different samples were more closely related to each other than they were to the other strains of domesticated ale yeasts.
“Because of that, we think that the kveik may form a separate branch on the family tree of beer yeasts. That being said, if we go and look for the most closely related yeasts, it’s a group of strains that includes some Kölsch yeasts and English yeasts, as well as a Lithuanian strain we looked at. So it’s possible that all these yeasts have a common ancestor at some point in history. But we can’t say that confidently yet, without whole-genome sequencing.”
Finding out more with whole-genome sequencing is expensive – $1,000 or $2,000 per strain. “But we think that because of the way the kveik have been maintained, and maintained for much longer, they haven’t been stuck in a lab for 100 years, this may be a new way for us to study yeast domestication without necessarily studying the commercial yeasts,” Preiss says. “We applied for a grant, and I’m happy to say that we did get funding to do the whole-genome sequencing for these kveik strains. We can hopefully have an answer some time in the spring, and hopefully say for sure that the kveik are a separate line on the family tree and have a little bit of a better idea of exactly where and when they broke off from the other beer yeasts. We’re using these Norwegian yeasts to really push brewing science, and yeast science, forward.”
Another question to be answered is: are there other yeasts like these? “Yes, of course, in Lithuania, and Russia and probably in other places,” Preiss says. “That’s a really exciting opportunity, to maybe look at these and start to understand these other yeasts that aren’t industrial and aren’t wild. The term I’ve started to use is ‘landrace yeasts’, which I think works well for an organism that’s been domesticated traditionally, without the involvement of industry, and because of that unique cultural framework, it has become genetically distinct from the other populations of that species. It suggests a third entire category of yeasts that have not really been explored in brewing.”
I was lucky enough to get to see a “Norwegian farm brewer” in action: Stig Seljeset, whose father was a farmer brewer, and who wanted to maintain the tradition. Stig brews at Borghild Tunet in Hornindal, “tunet” being the Norwegian for “farmstead”, home of Idar Nygård, deputy mayor of Hornindal, who has preserved the old farmstead much as it would have looked a century and more ago. The beer Stig brews is a “raw ale”, made without boiling the wort. The first step is to boil up water (which comes from a borehole up in the mountains, and contains lots of dissolved limestone/chalk) and branches of juniper in a large iron pot, perhaps 100 litres or so, suspended over the fire in the old farmstead kitchen (exactly the same way that Frank Clark does in his reproduction 18th century farmhouse kitchen in Colonial Williamsburg, Virginia). All the equipment is then scrubbed down and washed out with the hot juniper-water, before Stig uses milk churns to carry hot juniper-water to the “mash tun”, a blue 200-litre food-grade plastic tub set up in the garage across the farmstead yard.
The malt – on this occasion Munton’s pale lager malt from Suffolk, though Stig is happy to use whatever malt he can get hold of – is added, and mashing takes place at 68-70ºC. Once sufficient time has passed for conversion of starches to sugar, the grain is transferred by buckets into the “lauter tun” – another blue plastic tub, this one with a tap set in the bottom. Beforehand, Stig has set a wooden “filter” in the tun, above the tap hole, augmenting this with leafy twigs of juniper. The wort left in the “mash ” is then poured into the “lauter tun”, and allowed to strain through into milk churns, while more hot juniper-water is poured in to “sparge” the malt. A bag containing loose hops – Challenger this time, though again Stig isn’t fussy, and will use what he can get – is hung in the churn and the hot wort runs over the hops, like a teabag. This is the on