Saturday I brewed up a split batch of hoppy Koln Schwarzbier (using Koln) and Cascadian Dark Ale (Verdant), and was surprised to see the reportedly slow Koln take off like gangbusters and produce a huge krausen after only 14-15 hours, faster even than the usually fast Verdant.
After 3 days, the Koln’s krausen was already gone, and the beer was clearing very nicely. Hunh, I thought, this should be way slower.
Today, less than 4 full days after pitching, it looked so clear, I thought I’d hazard an early hydrometer sample. 1.004 already, from an OG of 1.064, or 93%. Way faster/more than I expected. It is my first time using Lallemand Koln yeast.
(Granted, I am fermenting a bit warmer than I’d have liked, about 68F. And, I did step-mash it for higher fermentability too. But still!)
Afraid that it was contaminated, I drank the hydrometer sample, and it was quite good – no contamination, no off-smells nor off-flavors. Yes, thinner body than I had hoped for, but quite drinkable. Might not even need to cold crash it. Looks great already.
I don’t really have any questions or concerns, but thought I’d throw this anecdotal data point out there for others to be aware of. It’s a slight tweak off a recipe I’ve made a couple times before, never gotten anywhere close to this attenuation (or speed) with other ale yeasts.
I’ll definitely use the yeast cake/slurry for a couple more round of other brews coming up, we’ll see if it does this again. In fact, I had a barleywine recipe I was going to do next, this 2nd gen slurry might be a candidate for half of that batch, just out of curiosity.
Anyone else get the Lallemand Koln to go 90+% attenuation? I’d heard 75%… which as why I step-mashed it, hoping for closer to 80%, maybe 82%.