Fermentation Temperature Control
As you learn to homebrew, you will hear over and over again that you will need to maintain control over the temperature of your fermentation to maintain some control over the profile of your finished beer. This is because yeast behaves differently when it ferments at warmer or cooler temperatures. There are easy ways to control the temperature of your fermenting beer, as long as you pay attention to what is going on in the fermenter.
Why control
Having the ability to control fermentation temperatures is important in your homebrewery because you need to provide your yeast with an optimal environment to ferment at its best. If it is too cold, your yeast may slow or stop. If it is too warm your wort may ferment too fast and produce off odors or flavors.
Temperature has a big impact on your beer because the yeast cells create different compounds, such as esters, and different effects at various temperatures. For example, some beer styles, such as many Belgian styles, are fermented at higher temperatures — up to 85 °F (29 °C) — because the style calls for fruity esters that yeast will create in a warm environment. Temperature control is also important when keeping things cool as well. For example, many lagers such as Pilsner, require long, cool fermentations to keep the flavor profile clean, crisp and free of fruity esters, which would be considered a flaw. The key is finding a method to control your temperatures that works in your brewery.
Location
If you don’t want to buy extra equipment, the most basic method of temperature control is choosing a location in your homebrewery that is conducive to brewing yeast. Decide what kinds of beers you want to ferment, determine what temperature ranges the yeast manufacturer recommends, and pick a well-insulated spot that doesn’t experience any big swings in temperatures.
Equipment
As you become more advanced, you can incorporate equipment in your homebrewery to help you maintain control over your fermentations. Like all beer making equipment, the choices for your homebrewery can range in price, however inexpensive setups are easy arrange. If your brewing area tends to get cold, try insulating your fermenter by wrapping it with a blanket or carboy wrap. If you need to warm it up more than that, you can try using a heated carboy wrap, or similar device, which are available at many homebrewing suppliers. If you need to keep your fermentation cool, try submerging your fermenter or carboy in an ice bath.
Pay attention
The most important means of maintaining control over your fermentations, however, is keeping a close eye on what is happening in your fermenter. Check your beer daily to be sure that the temperature isn’t increasing or decreasing too rapidly. The sooner you intervene, the better.
