F is for Fermentation

F is for Fermentation


Fermentation – that magical process by which sugar is transformed by yeast into alcohol and carbon dioxide.

Beer just wouldn’t be beer without fermentation.

Fermentation is an interesting process to observe. The yeast takes the sugar and breaks it down for energy to grow and reproduce. Natural by-products of this are alcohol and carbon dioxide gas. The result is a self-mixing cauldron.

The solid pieces in the mix will later settle to the bottom to form a layer called trub, which I’ll talk about in a later post. It’s the production of carbon dioxide that causes the apparent stirring.

Fermentation for beers and ales typically lasts about a week or two. Some brews are a little faster. Others can take a lot longer. But for the home brewer, it’s usually at least two weeks before the beer can be bottled, though I usually go four or more. (This let’s the brew clarify a bit.)

Other fermented drinks take even longer. For example, the honey mead I made last year fermented for 3 months, then conditioned for another 6 before I drank it.

The fun self-mixing stage as seen above usually only lasts a couple of days. Maybe a little longer, again depending on the brew. During this time, especially at the beginning, it’s critical that the brew be kept isolated from regular room air, lest it should become infected by airborne bacteria or wild yeast. To do this, an airlock is used to let carbon dioxide out but not let room air in.

When fermentation is done, the brew is still. There are no bubbles and the beer is totally flat (though it often still tastes good). Conditioning and carbonating are done when the fermentation is finished, and a couple of weeks later, the beer or ale is ready to drink!

I’m participating in the April A to Z Blogging Challenge. The goal is to write a post prompted by a letter of the alphabet on each day of April (except Sunday). My theme this year is brewing. Visit my other A to Z posts by clicking here.

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