What is Different for Brewing Lager Beer?
10.4 Yeast Starters and Diacetyl Rests There are two other items that are significant in brewing a good lager beer and I will describe them briefly. These are Yeast Pitching and the Diacetyl Rest. Lager brewing is best described in a book of its own and fortunately someone has done just that. See the Recommended Reading section in the appendices for more information. Because of the cooler temperatures, the yeast is less active at first. The best way to ensure a strong, healthy lager fermentation is to pitch a much larger yeast starter than you would for an ale. Where you would pitch a one quart starter solution of liquid yeast for an ale, you would use a 2 or 3 quart starter for a lager. This is the equivalent of about 1/2 to 3/4 cup of yeast slurry. In addition, the pitching temperature should be the same as the fermentation temperature to prevent thermally shocking the yeast. In other words, you will need to chill the wort down to 45 – 55 F before pitching the yeast. The yeast starte