Brewing Lagers for a Beginner

One of the keys to brewing great lager beers, really, is keeping the fermentation temperature cool. There is no way to sugar-coat the importance of this fact. Lager beers that are fermented warmer than about 58 °F (14.5 °C) often have fruity aromas and sometimes have strong solvent and sulfur notes depending on the yeast strain. Here at Springfield Brewing Company in Springfield, Missouri, we brew several different lagers and the strain we use for fermentation works really quite well at 54 °F (12 °C). Some brewers prefer cooler temperatures for lagers, and the lower end of fermentation temperature used by commercial breweries hovers around 46 °F (8 °C). In order for commercial brewers to consistently achieve these cool temperatures, jacketed fermenters that are chilled with glycol or ammonia are required. Homebrewers often do something similar by placing their fermenter in a refrigerator to maintain a cool environment.

I think we brewers are often times spoiled by technology and too frequently equate old or traditional methods with being outdated, primitive or simply wrong. While there is no question that technology allows us to do things differently than our forerunners, there is also no question in my mind that brewers from the past brewed some very fine beers. You are in an ideal location to brew lagers like they were brewed prior to the advent of commercial refrigeration. And this is brewing during the months of the year that are cool enough for the type of beer you want to brew. By looking at the average highs and lows in Toronto, there are about four months of the year that have an average daily temperature in the middle of the sweet spot for most lager strains.

My advice on brewing lagers is pretty simple. Begin with healthy yeast and pitch plenty of it. Targeting 15 million cells per mL of wort is a good rule of thumb pitching rate for normal gravity beer. If you pitch with a slurry that has a normal cell density of about 100 million cells per mL, you will need 3 liters for a 20-liter batch size. For all those gallon users, sorry for switching units, but I cannot think in gallons of wort when cell densities are also reported using metric terms. Three liters of yeast seems like a lot of yeast, but the numbers don’t lie. Proper pitching rate is a great start for great lager.

The second half of this piece of advice is to give your yeast the building blocks required for proper growth, and this means properly aerating your wort. If there is one gizmo every brewer should build or buy sooner than later it is a wort aeration device. During growth yeast cells need oxygen to synthesize sterols and unsaturated fatty acids, both of which are important constituents of cell walls.

And finally, let the fermentation take off in a cool environment with a maximum temperature not warmer than 54 °F (12 °C), and no cooler than about 45 °F (7 °C). This very well may be the average temperature of your garage. If you follow these three simple pieces of advice your lager fermentation should be complete in 10 to 14 days for brews with an original gravity in the 12 to 15 °Plato (1.048 to 1.061 SG) range, and longer for higher gravity beers. After fermentation is complete there are multiple options for packaging and cold conditioning, but these are not as critical to defining the beer flavor as is fermentation. Focus on the fermentation of lagers first, and the rest of the process will be become more apparent the more you brew and the more comfortable you become with these types of yeasts.

Response by Ashton Lewis.