What is the meaning of bottom fermentation?
Bottom fermentation refers to a fermentation method that uses bottom-fermenting yeast. This type of yeast settles at the bottom of the fermentation vessel.
This settling property allows beer to be brewed even in the summer, making it possible for people to enjoy beer all year round.
How does bottom fermentation work?
The bottom fermentation process involves the following steps:
Cold temperatures: Specifically, the temperature ranges from 41 to 50°F (5 to 10°C).
Long primary fermentation: The duration varies depending on the properties of the wort, but it typically lasts between seven (7) to fourteen (14) days.
Lagering: After the active fermentation, the beer needs to undergo cold storage, as its flavors are not fully matured at this stage. The temperature during lagering is typically around 32 to 39°F (0 to 4°C), which is just below freezing.
ACE 1000L Conical Fermentation Tank
What beers are bottom fermented at cold temperatures?
Lager is a beer enjoyed worldwide for its clear, mellow, and crisp characteristics, which result from long and cold fermentation. The key processes involved in brewing lager are cold fermentation and cold conditioning, also known as lagering.
Are all lagers bottom fermented?
All lager yeasts belong to the Saccharomyces Pastorianus lineage. This fact has been agreed upon by taxonomists, who are experts in classifying organisms.
Therefore, if you use a different yeast, you cannot claim to have brewed a lager. Even if you were to attempt a cold, bottom-fermentation process, chances are your wort would not ferment. However, we should never underestimate the potential of evolution and bioengineering.
Is ale a bottom-fermented beer?
No, ale uses top-fermenting yeast, which means it cannot be bottom fermented because this type of yeast tends to float and flocculate.
However, some ale strains can undergo lagering after warm fermentation. Yeasts in beers such as altbier or kölsch have evolved to work well with lagering, even before the golden age of lagers.
Is stout bottom fermented?
No, stout is a type of ale that is fermented using top-fermenting yeast. Therefore, it does not meet the criteria for bottom fermentation.