Fermentation: What to do when your homebrew ferments at too high of a temperature
Temperature control is a crucial part of the fermentation process. Often times, when a beer ferments at too high of a temperature, certain off-flavors or an increase in alcohol levels can occur. When a beer is described as too hot, this generally means a warming, boozy flavor. If there are no other signs of glaring off-flavors (such as infection or high levels of diacetyl for example), then a brew (while not ideal) can still be consumed.
When fermenting at home without much temperature control, it's important to always take note of the ambient temperature of the room your fermenters are in. During the peak of fermentation, temperatures can rise between 7-10 degrees. Avoid fermenting at too high of a temperature so that yeast won't produce such high alcohol content or estery off-flavors. Very high temperatures can also halt fermentation completely. Depending on what your recipe calls for, you can take precautionary measures by selecting yeast strains that do well in warmer situations to get that clean and properly attenuated brew.
There is one option that we would recommend if you are on a quest to save a hot batch. Bottled beer can be conditioned over time, which can help mellow out a boozy brew. Make sure that you are properly storing your bottles in a cool, dry place. Assuming that you have properly carbonated your brew and have experience bottling, conditioning can help alleviate some of the heat, but will most likely not "fix" your hot brew completely. We recommend this for many styles that can withstand some age -- obviously, not a good idea for hoppier brews such as IPAs that should be consumed as soon as possible.
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