Wednesday, September 30, 2009

Lager Lag Time & Lessons Learned

We brewed our first Oktoberfest last weekend. It was the first lager we ever brewed - we used the Marzen Madness recipe straight out of Brewing Classic Styles: 80 Winning Recipes Anyone Can Brew. The book recommends pitching cold - at or below the fermentation temperature of 50F. It also recommends pitching *a lot* of yeast, to ensure a clean fermentation with minimal byproducts the are associated with yeast reproducing (like fruity esters and buttery diacetyl). By pitching enough yeast, there is minimal reproducing to do, and the yeast can get down to the business of fermenting sooner.

The Classic Styles book is interesting in that it tells you how many "packs" of yeast to pitch. Lager recipes are all around 4 packs. I'd rather make a starter. I made a 1500ml starter in a 2000ml flask. Once that fermented out, I chilled, poured off the spent wort/beer, and added another 1000ml of fresh wort on top of the little yeast cake still in the flask. The day before brew day paranoia about having enough yeast set in, and I bought another Wyeast 2206 Bavarian lager to be extra sure.

Lesson learned: Since there is little krausen with lager yeast, next time I'll just make two back-to-back 2000L starters.

The night before brew day I put my starter and Activator pack (which I let swell at room temp for a day) in the spare fridge, which I had set at around 48F. On brew day, I cooled the wort down to just below 50F using ice water and a sump pump hooked up to my immersion chiller, much like described towards the bottom of this page. (I suppose I could have let the wort cool in the fridge overnight, but I really like my brew day to be a "day," and not have to aerate again.) After oxygenating the wort to the point the entire top of the carboy was filled with foam (by just trickling the wort through the funnel at the top), we let it settle about 5-10 minutes in the fridge while we cleaned up, then pitched the entire slurry and Activator pack. After a little carboy-shake, back in the fridge it went. I'd say the wort was around 52F, so I set the fridge a little lower to help cool it down below 50F.

The next morning, the fridge was at around 46F, and the temp strip on the carboy was around 48F. No visible signs of fermentation yet. I turned up the temp just a bit, so it was hovering around 52F. Roughly 24 hours after pitching, we had some small signs of krausen. 36 hours later we have this:

The temp is now stabilized around 50F, perfect. Of course, having only brewed ales we are used to seeing the fermenter bubbling like crazy 12-24 hours later. This was certainly a change of pace. I surfed this topic quite a bit, and guys were panicking after a day of no activity. I was ready to wait 3 days until I'd let myself worry about it, since the book said to pitch at around 45F and let it warm up to 50F over the next 2 or 3 days. I didn't pitch quite that low, but did chill it almost that low after pitching. So whatever that means, as long as you get your temps in the ballpark, aerate well, and pitch plenty of yeast... it's time to relax, have a homebrew and be patient!

We'll post a follow-up on how the beer tastes, in like, oh November? Jeez lagers take patience - cheers and good brewing!

UPDATE: Well, it was more like January when we served this, but mighty tasty! Our friends certainly drained it. Just a touch of diacetyl - an issue we're working on.  Going to try doing a diacetyl rest sooner and longer next time.

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