maximum fermenting temperature
This is also why I ferment ale in the winter and mead in the summer, when my basement is in the proper temperature range for each type of fermentation. Normal ale fermentation temperatures range from 68 to 72 Â°F (20 to 22 Â°C) and lager fermentation temperatures from 45 to 55 Â°F (7 to 13 Â°C). Also keep in mind that the heat generated by an active fermentation can warm a typical 5-gallon (19-L) batch of beer by 10 to 15 degrees Fahrenheit (5.5 to 8.3 degrees Celsius).