[ScallyWag]

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%.

[denny]

Attenuation is at least as dependent on wort as on yeast

[ScallyWag]

Attenuation is at least as dependent on wort as on yeast

Apparently I have just demonstrated that, without intending to.     Oh well, not what I was intending, but this is already a very nice beer -- and in less than 96 hours to boot.  Who needs Kveik??

Meanwhile the Verdant batch (same exact wort) is still chugging along, probably at least 2-4 days away from being done.  No gravity check on that one yet, as it's clearly not even close to the stage of the Kolsch.

[Andy Farke]

Fascinating data point!


I absolutely love the Koln strain. Looking at two recent kolsches made with the yeast, I hit 78% and 79% attenuation with mash temps of 150 and 152. I could probably nudge it up a bit higher with a step mash, but am quite happy with the results on these beers as they were.

[fredthecat]

just a data point on attenuation.

i was doing some overnight mashes at ~149/150F temps and getting mid to high 80s attenuation with all basemalt worts and lager yeasts. the tricky part was getting consistency, and being able to plan the OG  with a somewhat accurate expected FG to not get a beer that is say 6% ABV isntead of 5%

i would do it again, and i noticed no flavour issues with overnight mashes. i didnt check pH at start and end but hope to this time around