Monday, January 19, 2009

Krausen - Pilsner fermentation

Well, the Pilsner has been fermenting for about a week now and is still going strong in the Lager fridge. The temp in my converted chest freezer is set at about 48 degrees and it generally has been fluctuating between 48 and 52 since fermentation began last Tuesday (1/13). I'm guessing that it will take about another week before fermentation slows and I can siphon it off into a secondary fermentation carboy and drop it down to lagering temperatures (32-38F) for another 4 weeks. My plan is to rack the beer off of this yeast next week on the same day that I brew the next beer, a Maibock, that will go on top of the plentiful yeast cake produced during the Pilsner fermentation. This will be my first time re-using yeast like this, so fingers are crossed. The idea is that why not use the yeast again since you have so much at the bottom of the fermenter. This supposedly can be done up to 3 times before the yeast get "stressed". Each beer should be successively stronger in order to to make use of the additional yeast numbers. The Maibock should definitely be stronger as I'm shooting for a beer near 7% abv to ring in the spring season. Maybe I'll call it Cinco de Maibock...or F├╝nfte der Maibock(in German).

These pics show the foamy head known as "Krausen" that forms on top of the beer while it is fermenting. This is pretty subdued at about 1-2 inches depth compared to an ale(which is top fermenting as opposed to bottom fermenting lagers like this) which can get really rocking and sometimes blow through the airlock.

It's really good to see this beer ferment as there was some doubt initially with the yeast. I ordered the yeast the week before Christmas and it was delayed getting here. Our temps were well below zero during that period and the yeast(2 packs) arrived frozen! Not a good thing as yeast should be kept refrigerated, but freezing is very bad as the crystallization that occurs breaks and kills the living yeast cells. The yeast packs felt slushy when I got them! So I made a 3 liter starter in hopes to multiply what cells, if any, did make it and it appeared to work. I also recently got a stirplate and Erlenmeyer flasks for making better starter yeast cultures and this seems to have really helped. I'm looking forward to seeing how much yeast is actually produced at the bottom of this fermentor.

Here's the info on the yeast strain I'm using from Wyeast.

YEAST STRAIN: 2206 Bavarian Lager
Used by many German breweries to produce rich, full-bodied malty beers. Good choice for Bocks and Dopplebocks. Benefits from diacetyl rest at 58°F(14°C) for 24 hours after fermentation is complete.
Origin: Flocculation: medium-high Attenuation: 73-77% Temperature Range: 46-58° F (8-14° C) Alcohol Tolerance: approximately 9% ABV

1 comment:

Cate said...

I started growing hops 2 years ago and wondered when was the right time to harvest. I sent some friends of mine about one lb. of it and they made there own beer with it. I am following your blog to get some tips! Hope you post something on harvesting hops. I live in the midwest.