Chapter 10

What is Different for Brewing Lager Beer?

When to Lager

Note: This page has been updated in 2018 to reflect the better information in the 4th edition (2017, Brewers Publications).

Lager yeast ferment at lower temperatures than ale yeast, typically 10-15F (5-8C) cooler than ale yeast, depending on the strain. Typically, lager yeast pitching rates are twice that of ale fermentations. Other than that, everything is nearly the same between ale and lager fermentations. The only additional differences are the more likely use of a diacetyl rest (see previous page), and the actual lagering step. 

The lagering step consists of chilling the beer (slowly, about 1F per hour) down to about 35F (2C) for a couple weeks to facilitate the clarification of the beer. The cold temperature assists the coagulation and settling of haze (excess protein and polyphenols) and yeast. There is very little yeast activity once you get below 40F (4.4C), although some lager yeast strains can do a little bit of sulfur reduction and other maturation. The vast majority of maturation by the yeast will occur during the diacetyl rest! Therefore it is important to give the yeast time to fully maturate the beer at the fermentation temperature, or at a warmer temperature (the diacetyl rest) to help maintain yeast activity. After 1-3 days (or a week or two if you are busy with other things) the beer will be done and ready to lager.

However, if you are going to prime and bottle your beer, it is best to do that before lagering, when there is more yeast in suspension. Prime and bottle just as you would for ale beers. Give the bottles time to carbonate at room temperature (about 2 weeks), and then you can chill them to lagering temperatures.