Krispy kveik review and fermentation performance
I've done a number of posts now on kveik (traditional Norwegian farmhouse brewing yeast). We've shown that kveik vary in their response to high temperatures - some like it hot and some don't (like Lutra kveik). We've compared fermentation speed (kinetics) of Voss, Hornindal, Lutra, and "typical" commercial ale yeasts at various temperatures. And we've also found that the optimal fermentation temperature for Voss kveik is 37-38ºC, with temperature stress already apparent at 40ºC. Now I'd like to join the search for a 'clean kveik yeast', which has been going on for quite some time now (1)(2).
The story on clean kveik centers around brewers who would like to make clean and crispy beers quickly; sometimes this is due to a lack of adequate temperature control but often it is simply about the bottom-line of being able to turn around a crushable beer fast. Beers made with kveik are known to ferment and mature quickly, thus directly affecting the bottom line of the brewery by allowing a quick turn-around of clean, crispy, highly drinkable beers. I won't get into the debate about naming (i.e. pseudo-pilsner vs 'lager-like') because I don't think it's very helpful and because this is comparing apples and oranges.
Several kveik blends and isolates are championed as 'clean':
Lutra kveik (a single isolate of Hornindal from Omega labs) is a 'shockingly clean' kveik when fermented ~20-22ºC
Krispy kveik (a blend of 2 isolates from the Skare kveik, Escarpment labs)
Oslo kveik (from Bootleg biology or the original farmhouse version).
I've already tested the fermentation kinetics (and sensory properties) of Lutra kveik. So in this article I wanted to assess the fermentation kinetics and sensory properties (taste, aroma, clarity) of Krispy kveik from Escarpment labs. I also compare Krispy kveik to Lutra kveik, Hornindal, and Voss kveik.
Methods:
I used the same base beer (a Kolsch-type beer) as in all of my previous kveik experiments so that I could directly compare the flavour contributions of each yeast and the fermentation properties.
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60% Pilsner malt
38% Vienna malt
2% Munich malt
Mashed at 65ºC for 1 hour, 78ºC mashout for 1 min, batch sparge
Mash pH of 5.45-5.5 to counteract kveik pH drop
OG 1.048
FG 1.008 (apparent attenuation varied from ~82%)
60 min boil
23 IBU Hallertau magnum at 60 min
Half a teaspoon wyeast nutrients at 10 min
0.7 IBU Hallertau Mittelfrueh at flameout
Chilled to 25ºC using immersion chiller
Aerated with a 5 micrometer stainless steel airstone (air) for 4 minutes
Pitch rate: 1 pack per 5 gallons (standard recommended pitching rate)
Fermented 25ºC
I maintained temperature using a fridge fermentation chamber for my fermentation vessel coupled to an inkbird and heating pad. This allows temperature control of +/- 0.5ºC from 4ºC to 41ºC.
Once the fermentations finished (click here and go to the bottom to see how I calculate this), I transferred each beer to a corny keg and carbonated to 2.5 volumes.
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I followed the gravity and instantaneous CO2 evolution rate (CER) over time to track fermentation progress at the different temperatures. As a brief reminder: CER is an instantaneous measure of yeast activity (rate per unit time) which correlates really well with sugar consumption and yeast activity.
Results:
Figure 1: Measured gravity and CER (CO2 evolution rate) over time for Krispy kveik fermented at 25ºC
I chose 25ºC because this was the temperature that Escarpment labs used for their sensory/kinetics experiment. From the gravity and CER curves I concluded the following:
A) At 25ºC, gravity starts to decrease measurably 90 minutes after pitching and CER starts to increase exponentially 90 minutes after pitching, so Krispy starts fermenting really fast!
B) Terminal gravity is reached at approximately ~77 hours.
C) CER indicates that fermentation finishes at ~81 hours (the CER threshold for this is 0.0001 mol CO2/min).
Figure 2: Measured gravity and CER (CO2 evolution rate) over time for Krispy kveik fermented at 25ºC, Voss kveik (22ºC), Lutra kveik (22ºC), and Hornindal kveik (22ºC)
In Figure 2, I compare the performance of Krispy kveik fermented at 25ºC to Hornindal, Lutra, and Voss kveik that were all fermented at 22ºC. I know that this is a 3ºC difference, but I chose 25ºC for Krispy because this the temperature that Escarpment did their initial sensory experiment at.
C) The initial gravities vary a bit, but it looks like Krispy reaches terminal gravity at about the same time as Lutra and Voss, with Hornindal being noticeably slower.
D) The CER curve shows a similar pattern to the gravity curve. Voss seems to have the highest peak CER and Lutra seems to have the lowest peak CER.
Figure 3: Time to finish fermenting, max gravity points per minute activity (MGPPM), and max CER for Krispy kveik (25ºC), Voss kveik (22ºC), Lutra kveik (22ºC), and Hornindal kveik (22ºC)
Figure 3 shows a more comprehensive comparison between the 4 kveik strains fermented at 25ºC (Krispy) or 22ºC (Hornindal, Lutra, Voss).
Lower time to finish fermentation = faster fermentation
Higher maximum CER production = faster fermentation
Higher maximum gravity points per minute (MGPPM) consumption = faster fermentation
E) Voss is the fastest to finish fermentation in the 22-25ºC range. Consistent with this is that Voss has the highest maximum CER and the highest maximum gravity consumption.
F) Krispy takes about 77-80 hours to finish fermentation (from an OG of 1.048), about the same time as Lutra (~88 hours to finish fermentation).
G) Hornindal is the slowest to finish fermentation in the 22-25ºC range and has the lowest max CER and max gravity consumption rate.
Figure 4: Sensory properties of Krispy kveik fermented at 25ºC
Finally, I wanted to assess the sensory properties and clarity of this Kolsch-type beer made with Krispy kveik. Figure 4 depicts the flavor and aroma I perceived after about 10 days in the keg (carbonated to 2.5 volumes).
F) Light but perceptible fruity/estery aroma and flavour. There were no noticeable "alcoholic" notes coming through, unlike with Voss kveik. I did get a bit of the "kveiky" acidity/twang, even though I adjusted the mash pH to 5.5 at mashout to counteract the pH drop. However, the kveiky-ness didn't come off strong or harsh and did not dominate the flavour profile. I also tasted a bit of ripe sweetness ('red apple'). The beer has a light body and medium mouthfeel, but was still highly drinkable and quite 'crisp'. I would say the final result was fairly neutral but the fruity esters were definitely still quite noticeable. In my opinion, Lutra is a bit more 'clean', more 'crisp', and more neutral. The light lemony-dough taste of Lutra also complements clean beers better, in my opinion.
G) I did not add any clarity process aids during the boil or post-fermentation to assess the clarity of the resulting beer without these additions. Krispy flocculates and sediments relatively well, but the result was not crystal clear without the addition of gelatin.
Figure 5: Clarity/colour of Kolsch-type beer fermented with Krispy at 25ºC
Conclusions:
Overall, expect you should expect a refreshing and pleasant beer with a light fruity esters when fermenting with Krispy kveik at 25ºC. Performance is very robust and reliable: fermentation takes about 77-80 hours at 25ºC at standard pitching rates. I don't think it's the absolute best choice for a 'pseudo-lager' (I slightly prefer Lutra), but it produces a decent clean ale.
1) https://escarpmentlabs.com/blogs/resources/the-search-for-krispy-clean-kveik-yeast
2) March/April 2021 Issue of Zymurgy Magazine, 'Brewing Clean beers with kveik yeast'. (https://www.homebrewersassociation.org/zymurgy-magazine/march-april-2021/).