I went ahead and brewed a Kölsch, and the brew day went off without a hitch. I knew there would be a problem getting this beer to clear properly but I didn’t realize how stubborn this yeast can be. As I mentioned before, I used this yeast to make a cream ale and it was relatively clear when I racked it to the keg. What I failed to fully grasp was that I actually let that beer sit untouched for over three months at my parents’ farm in Pennsylvania before I finally made it back to check on the beer.
When I brewed the classic Kölsch recently, I allotted roughly one month of dedicated lagering before I would even touch the beer. I thought it would be plenty of time to fully clear this beer. After two months of lagering near freezing temps, the beer was still cloudy and smelled of fresh yeast. Finally, fed up, I broke out my plate filter that I had purchased a while ago but eventually imagined I would never really use.
I had already carbonated the Kölsch which causes problems during filtration so I left the pressure relief valve open on the keg for three days but I left it in the keezer so most of the carbonation stayed in solution. Running out of time, I had to begin filtering. What should have taken 45 mins turned into a 3 hour ordeal because I had to lower the pressure in the keg to 3 PSI to allow the CO2 to escape. When I helped out recently at Carton Brewing, where they brew their flagship Boat beer with the 2565, the head brewer Jesse told me how tough it is to clear this yeast even with a diatomaceous earth filter so he only filters half the batch.
I will say it was worth it. I’ve never had a beer this clear. I used the coarsest filter and I do think some body was stripped from the beer and in turn some of the hop bitterness. When I brew it again I will bump of the bittering addition just a bit (really for my personal preference and not to keep it within style guidelines).