Make this beer a lager... if you want. – Monthly Brews
Make this beer a lager... if you want.

The January box came with free lager yeast. We wanted to encourage people to try their hand at lagering, but if you are new to brewing you might have some questions about lagers. Cold fermentation temp is the key difference between ales and lagers, but there is more to know about it if you want to start lagering your beers. Here is a quick breakdown of cold fermentation using most lager strains of yeast.

Lagers typically have a reduced ester profile with discernible malt character. It is very important to recognize that pitch rate is directly related to the amount and intensity of ester production. Increasing the quantity of yeast pitched is the most effective method of reducing the ester profile in the finished beer. You will need to double the yeast you would typically need in an ale fermentation.

Fermentation should take 2-4 weeks at 52 °F. The best temperature will depend of the yeast strain used and what you want to get out of the flavor profile. After fermentation you will want to raise your temperature as close to 62ْF as possible. This is called a diactyl rest. The increase in temperature will both assure fermentation is complete, drive of any remaining CO2 that might cause “of favors” and clarity issues, and finally, it will allow the yeast to absorb the diacetyl produced by fermentation.  

A secondary fermentation at a temperature below the primary fermentation allows for a slow reduction of any remaining fermentable sugars. This secondary fermentation can take from one to three weeks at temperatures starting between 39-45 °F and slowly falling to as low as 33 °F. The length of the secondary depends on the amount of fermentable sugars remaining. 

Lager roughly means “store” in German. It is a time when harsh favors from fermentation are mellowed. Yeast re-absorb some of the ester compounds from fermentation as well as some of the sulfur compounds. Malt tannins coagulate with haze-forming proteins and precipitate out along with some sulfurous compounds. Temperatures should remain very stable during lagering, generally in the range of 33-36 °F. Contact with oxygen at this point is very detrimental to beer favor and should be avoided at all costs. Lagering time depends on many factors. If a cold secondary fermentation was employed, then the length of the lagering period can generally be decreased. A lagering period of two to eight weeks is typical.The higher the ABV of the beer the longer you may want to lager also.  

While many homebrewers have converted refrigerators or freezers with external thermostats to carefully manage their lagering temperatures, you can make a good lager with just a cool basement. If you can get sub 60 °F in a basement or cellar for your primary fermentation and secondary fermentation, then keg or bottle from there, you can make a decent lager that can be crisp and refreshing without the added cost of a dedicated feremtation chamber. Give lagering a try this winter if you can, the worst thing that will happen is you will make beer... and that's not so bad.

If this quick rundown peaked your interest in lagering there is another article you can read from the American Homebrewers Association 

February 20, 2018 by Ross Metzger

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