In a recent episode of The Brewing Network's Sunday Session, the traditional, low-and-slow method of lager fermentation was compared to a more accelerated schedule championed by Mike "Tasty" McDole.
The two fermentation styles were executed on a split batch of wort and compared side by side. Though a riff existed on the overall favorite, the Brewcasters could not discern any fermentation flaws in either sample.
I love lagers. Pils, Marzen, Doppelbock, Helles, Baltic Porter, Altbier, etc.; great beers, but with the coddling required to ferment and condition, I don't often commit to brewing them myself. In light of the above experiment, I decided to give the "Tasty Lager Method" a try.
McDole starts with plenty of healthy yeast slurry, preferring WLP833 - German Bock Yeast (the Ayinger strain). He pitches at 55F and keeps a close eye on the progress of the ferment.
After the gravity drops 50% of the way to terminal gravity, he raises the temperature to 58F.
After the gravity drops 75% of the way to terminal gravity, he raises the temperature to 62F.
After the gravity drops 90% of the way to terminal gravity, he raises the temperature to 66F and holds until fermentation is complete.
Though it goes against the traditional method of lager fermentation, this procedure parallels a normal, healthy ale fermentation. After the initial growth phase, a slow. steady rise in temperature towards the end of fermentation helps yeast attenuate properly and clean up fermentation byproducts. Since the vast majority of esters we want to avoid in crisp, clean lagers are produced during the initial growth phase, it makes sense to reel in the temperature initially, allowing the yeast an increasingly warmer environment to complete fermentation.
(Nearly all the information in the above paragraph on healthy fermentation was taken from Yeast by Jamil Zainasheff and Chris White. If you are interested in brewing GOOD beer, read it.)
Application in the SHPB
I brewed two lagers in succession with this method: a Munich Helles and a German Pils with sweet corn.
I kept tabs on each fermentation, taking a gravity sample each day and adjusting the temperature as needed.
Both brews are currently kegged and on tap. I will post recipes and tasting notes later this week, hopefully after receiving some critical input from more experienced tasters. Results, so far, have been promising (not to mention delicious!).