Chilling is an integral part of the brewing process. The quality and integrity of the finished product depend on precise temperature control and reduction at critical stages of the brewing operation.
Keeping your beer at a consistent fermentation temperature is more important than ever. While many strains of yeast can cope with inconsistent temperatures, most brewer’s yeasts are damaged in the temperature range of 40°C and above – stopping fermentation. Even if you’re lucky and the yeast continues to do its job, there’s a good chance you’ll notice weird off-flavors from yeast in your beer. So the best course of action is to follow the temperature recommendations on the package of yeast you are using. This article will also discuss the importance of temperature control.
How to achieve wort cooling
- A total volume of wort to be cooled (usually expressed in BBL/barrel volume).
- Required knockout time (cooling time required for optimization process).
- Initial wort temperature and desired final wort temperature.
- Will the cooler also provide cooling capacity for other brewing processes?
Why control the fermentation temperature?
- Fusel Alcohol: Often considered a hot alcohol flavor that almost tastes like wine or vodka. This tends to go away during conditioning.
- Esters: Often thought of as fruit, banana, pear, or nail polish removers. While certain esters are desirable in certain styles, they often hit you over the head when they shouldn’t.
- Acetaldehyde: Often identified as green apples, raw pumpkin, or zucchini. Acetaldehyde is a natural by-product of every fermentation, but under uncontrolled conditions, it can appear in excess.
Fermentation temperature control
If you keep your yeast at around 66-68°F, you’ll at least take a step in the right direction and give your beer a fighting chance. Assuming you ferment in a cool environment, your fermenter may heat up during fermentation, but at least your starting temperature is low enough to handle the increase in temperature.
While this method helps to cleanse your beer, I still recommend a precise method of controlling the temperature of the fermentation so you don’t get away with the results.
Keep the fermenter warm
Fermenting too cold can also stress the yeast and lead to unexpected results. Many expensive conical fermenters can be equipped with heating pads. The heater ensures that your beer doesn’t drop below your target fermentation temperature or cause your yeast to go dormant in a very cool environment.
Many brewers raise fermenter temperatures (72-74°F) towards the end of fermentation to ensure complete fermentation and cut detectable diacetyl. Yeasts are happiest at warm temperatures and actually do their job better at warmer temperatures, it doesn’t always produce the results that brewers hope to produce the best beer possible.