All beer requires fermentation to allow the yeast to convert the sugars inside the wort into ethanol and carbon dioxide.
Without the fermentation process, there will be no beer. Once fermentation is complete, the grain mash, sugar, hops, and other ingredients have completed the transition into beer as we traditionally define it.
Yeast is a microorganism that converts sugar into ethanol and carbon dioxide, so since grains, which contain sugar, and yeast are both integral to beer brewing, then all beer is fermented.
Stronger beers such as Westmalle Tripel, Hoegaarden, and Echt Kriekenbier are all double-fermented, which is not exactly the same as secondary fermentation. Double-fermenting is achieved by bottling the beer and adding a different yeast strain that produces bacteria-killing acids right into the bottle.
We’ve all heard of a ‘beer belly’, which is the extra abdominal fat or bloating that can happen when someone is regularly drinking traditional, single-fermented beers. The liver will burn off alcohol before it burns fat, so consuming large quantities of alcohol means those calories will take a long while to be processed by the liver.
If a beer doesn’t ferment, then it’s not beer! Fermentation is a critical step in brewing beer. If the yeast fails to convert sugars in the grains into alcohol and carbon dioxide, then you don’t have beer – you still have the wort you started with, which is just the grain mash and water.
Fermentation happens in food the same way it happens in beer: yeast converts carbohydrates (which are made up of fiber, starch, and sugar) into carbon dioxide and alcohol. This changes the food’s texture, aroma, and taste.
Alcohol is a natural byproduct of fermentation, so anything that has been fermented contains varying amounts of alcohol. Most fermented foods contain such a small amount of alcohol that it’s unmeasurable. If there is carbonation present – for instance, in a sourdough starter – the alcohol content is slightly higher.