WHAT KIND OF FERMENTATION OCCURS IN YEAST-FERMENTED FOODS?

 If you haven’t heard about how great yeast-fermented foods are for the human body, you must have been living under a rock. Kombucha is now on every market shelf, kimchi is available widely, and virtually every human during the global lockdown had their own sourdough starter kit on hand.

Yeast-fermented foods have been around, and are a staple, of pretty much every civilization since the beginning of… well… civilization.

Why?

What kind of fermentation occurs in yeast-fermented foods, and why is it so good for you?

YEAST

Yeast is a single-cell organism that has been around since the beginning of time, as it is a type of fungus, and fungi are the first known living organisms on earth.

It provides myriad benefits to the human body, just like other fungi. In particular, yeast is good for your digestive system, keeping it healthy and in good balance. It also promotes a strong immune system, helping your gut absorb vitamins and nutrients and fighting disease.

Yeast needs food, warmth, and moisture to do its job, which is, essentially, to convert sugar and starch into carbon dioxide, alcohol, and acids. That process is what we call fermentation.

In beer, wine, and other alcoholic beverages, we need yeast to make the alcohol.

In bread and other foods, we need yeast for rising and expanding.

The alcohol preserves food and beverages, so originally, the fermentation process was undergone for that purpose alone, without any knowledge as to the true health benefits of fermentation.

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FERMENTATION HEALTH BENEFITS

When added to food, yeast produces acids and alcohols that preserve the food and convert it to an even healthier version of its original state.

Fermented foods and drinks undergo a microbial growth and enzymatic process that produces new compounds in foods.

The end result of fermented foods will be a slightly sour flavor.

Two kinds of fermentation exist.

SPONTANEOUS FERMENTATION

Spontaneous fermentation is what has occurred throughout history with fermented foods and drinks. The cook, baker, or brewer, combines the ingredients and then leaves the combination up to nature. At that point, whatever yeast or bacteria happen to be present in the air will ferment the foods.

NATURAL FERMENTATION

Natural fermentation occurs when a person adds yeast intentionally to the food or drink. An example of this process would be kimchi, sauerkraut, beer, wine. What was once spontaneous can now be manipulated and controlled by adding yeast or bacteria and then creating a controlled environment wherein no further yeast or bacteria can enter the mix.

Either of these processes is perfectly acceptable, but for commercial cooks, bakers, or brewers who are seeking a consistent product, and a following that expects that product, natural fermentation is preferred.

If you’re at home, if you’re experimenting in your kitchen, be it commercial or domestic, it can be interesting to see what happens with spontaneous fermentation and then control for which factors you can to then produce a consistent product.

WHAT TYPE OF FERMENTATION OCCURS?

In yeast-fermented foods, with or without oxygen, yeast breaks down the sugars and starches into alcohols and acids, making foods abundantly more nutritious and preserving them so you can store them for longer periods of time without worrying about spoiling.

In drinks, yeast and bacteria convert starches or sugars into lactic acid, and this process does not require heat.