Lagers can be a tricky lot, the yeast is kinda finicky, and will not yield its full potential unless certain minimum conditions are met. One of the hardest conditions to meet (mostly for Homebrewers these days) is fermentation temperature. Everyone knows that lagers work better at lower fermentation temperatures, but just how low? Lager comes from the German word to store, this was because since the lager beers fermented at a lower temperature, they took longer to ferment, but also tasted much cleaner and crisper as a result of low phenol and ester production. Here are some quick tips and info if you are planning on doing lagers at home or on a commercial scale:
-Budget at least three weeks for fermentation, and an additional week for aging, start checking gravity readings in the middle of the third week (unless it seems to be going vigorously, then use your best judgement)
-Ensure that fermentation stays between 50-60 degrees, this is a general guideline only, and different yeasts might perform best slightly above or below this range, this is best done in a glycol cooled fermenter, or at the homescale, a fridge hooked up to a temperature control unit
-If you are fermenting your lager yeast like an ale strain (and there are some styles where this would be appropriate) careful control of fermentation temps is critical, fermenting longer than a week and a half at ale temperatures runs the risk of imparting undesirable flavors from yeast autolysis and fermentation products (again this is a general guideline, use your best judgment and regular tasting to determine the best time to start cooling down)
-Pay attention to how your yeast flocculates, lagers, as with ales, can vary wildly among strains with how they floc out. Ensure that your pitching rates reflect you’re yeasts flocculation rates, if it flocculates very quickly, pitch more to ensure that enough will stay active to properly attenuate your beer.
-For “authentic” lagering conditions (ie in your basement) you can start you’re brewing in early fall and lager just until the onset of winter, this reflects the traditional german way of brewing in which the brewing of lagers was banned in summer because the temperatures were to warm. This is why Marzens came into popularity, because the “beers of march” had to last all summer, they were brewed a bit more robustly, and when fall came again, they had to finish all their left over beer before they started brewing again. This, combined with a wedding party of epic proportions, is where the style of Oktoberfest originated.