Why is bread soft?

Why does Swiss cheese have holes?

Why is vinegar sour?

The flavors of these foods can vary widely, but they are all the result of fermentation—the process of microorganisms breaking down sugars and releasing some delicious byproducts.

Let’s look at yeast first.

Yeast is a single-cell fungus used in making bread, beer, wine, and many other products.

Yeast breaks down carbohydrates, such as sugar, to obtain the molecules and energy it needs to do its work.

They work in two ways: the oxygen-dependent, or aerobic, pathway, and the oxygen-independent, or anaerobic pathway. The anaerobic pathway is also called fermentation.

When you bake bread, yeasts can work both ways, but they usually begin anaerobic fermentation first.

During this process, ethanol and carbon dioxide are produced.

Oh no, bread is not alcoholic.

A small amount of alcohol evaporates during the baking process.

In the aerobic (oxygen-dependent) pathway, yeast breaks down part of the sugar and then produces carbon dioxide gas (Co2), as well as water.

During these two processes, carbon dioxide accumulates to form air bubbles, which are trapped by the gluten to form a sponge-like structure that makes the bread fluffy.

Yeast is also needed to make wine.

However, the brewing unit maintains low oxygen levels to allow the yeast to break down the sugar through fermentation, the anaerobic pathway.

In the beginning, the wild yeasts contained in the grapes ferment themselves.

However, in order to unify the fermentation results, most winemakers carefully select and add some yeast strains that can tolerate high concentrations of alcohol.

The yeast breaks down the sugar in the grape juice, and as the sugar decreases, the alcohol concentration increases.

This doesn’t mean that sweeter wines don’t have high alcohol content either.

Different types of grapes contain different amounts of sugar, and additional sugar can be added.

What about carbon dioxide?

Expelled from the vent.

Carbonated alcoholic beverages, such as champagne and beer, will be stored sealed during primary or secondary fermentation to trap carbon dioxide in the bottle.

Speaking of wine, that brings us to the second food-producing microorganism to be introduced: bacteria.

A particular strain softens the taste of certain acidic compounds in grape juice, which affects the flavor of some red wines and Chardonnays.

Another type of bacteria, called acetic acid bacteria, is less popular in wine but has its place.

If oxygen is around, these bacteria convert the ethanol in the wine into... acetic acid.

Continue this process and you will create vinegar.

Bacteria are also key to making cheese.

To make cheese, you put bacteria into milk.

These bacteria quickly consume lactose (a sugar) and produce lactic acid, among many other chemicals.

The milk therefore becomes more acidic, and the proteins it contains begin to clump and curdle.

That's why spoiled milk comes in lumps.

Cheesemakers often add an enzyme called rennet, which is found naturally in cows, sheep, and other mammals, to aid fermentation.

Eventually, those small curds turn into large curds, which are squeezed to squeeze out the water, creating hard cheese.

Different strains are used to make different cheeses.

For example, a certain type of bacteria that releases carbon dioxide gives Swiss cheese its characteristic holes.

Some cheeses, such as Brie and Camembert, also use another type of microorganism: mold.

This way your kitchen functions like a biotech laboratory, using microorganisms to grow delicious food.

Yogurt, soy sauce, sour cream, sauerkraut, kefir, cabbage, kombucha, cheddar cheese, halal bread, pita bread, naan bread.

But don’t eat it all in one go.

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