How does beer become alcoholic in the production process?

Question

How does beer become alcoholic in the production process?

In: 16

Answer 1

It comes from a process called “fermentation”, which is done by yeast (and sometimes some bacteria along with the yeast) in beer.

Yeast are little tiny single-celled fungi, kind of like mushroom germs. They eat sugar and poop out alcohol (and some other stuff).

Yeast are added to (most) beer where they start eating sugar in the unfermented beer and they poop out alcohol and they divide to make more and more yeast. Eventually they either eat so much of the sugar or produce enough alcohol that they have to slow down and stop and fermentation effectively ends. Some rare beers use wild yeast and bacteria present in the environment (as yeasts and bacteria are *everywhere*) to ferment the beer, but that’s quite rare.

The process of turning sugar into alcohol also releases carbon dioxide. If yeast poop out alcohol, you can think of them as farting out CO2. That CO2 is what traditionally carbonated beer (though these days just adding CO2 under pressure after fermentation is pretty common).

There is a lot of variability in how yeast ferment stuff. Different types of yeast will give different results. Some yeast make very little alcohol when they eat sugar, and yeast like that can be used to ferment things that aren’t very alcoholic. Some make a lot of alcohol when they eat sugar. Some yeast will die at very low concentrations of alcohol, so they’ll poison themselves before the beer gets very boozy and fermentation will stop. Some can withstand pretty high concentrations, even over 20% alcohol by volume, which is much higher than almost all beer. Getting to 20% ABV also means you have to start with a huge amount of sugar dissolved in your unfermented beer.

Yeast also release other stuff during fermentation, which can lead to a lot of different flavors. Some traditional Belgian strains can produce a lot of fruity, spicy flavors, like banana and clove. Some traditional German strains are very “bready”. Some wild strains can make really funky, weird flavors indeed, which can be unpleasant if not used expertly, but used well can make some of the best beer in the world in my opinion.