Everything You Need To Know About Fermentation

Cooking at its heart is a transformational process. We take raw ingredients and change them into something new, something edible, delicious, and nourishing. Heat is one of the most obvious tools we use. Understanding ingredients is another. We think about salty, sweet, acidic, sour, and fatty flavors. All of these are important.

But there is another tool that is just as powerful and far less understood. That tool is fermentation.

Fermentation is a category all its own. It is responsible for many of the foods we love most. Cheese is fermented. Salami and other cured meats are fermented. Wine and beer are fermented. Beer is often called liquid bread, while bread could be called solid beer. All of these foods live under the same umbrella.

Our mission as cooks and bakers is simple. We want to unlock the full potential of flavor trapped inside our ingredients. Fermentation is one of the best ways to do that.

What Is Fermentation?

At its most basic level, fermentation is biological activity. Yeast and bacteria act on the sugars in food and convert them into acids, alcohol, and carbon dioxide.

That is Fermentation 101.

If you understand that one idea, you already have a strong foundation. From there, you can begin to use fermentation intentionally to create better tasting food.

Time and temperature are the two factors we can control. Together with the ingredients, they form what I call the baking triangle. Change one point of the triangle, and the others are affected.

Microorganisms are very sensitive to temperature. Yeast works faster in warmer environments and slower in cooler ones. For example, a dough that doubles in size in two hours at 80 degrees will double in only one hour at 97 degrees. Drop the temperature to 63 degrees, and it may take four hours instead.

At 40 degrees, yeast activity nearly stops. That is why dough can be held in the refrigerator for days without over fermenting.

Bacteria behave in a similar way, but they usually work more slowly because there are fewer of them present. In sourdough, bacteria contribute acidity and complex flavor while yeast provides rise.

Understanding how time and temperature affect these organisms allows us to control flavor and texture with great precision.

Why Slow Fermentation Makes Better Bread

One of the biggest breakthroughs in my baking career came when I realized a simple truth.

Slow rising bread tastes better than fast rising bread.

But why?

Fermentation is not only about yeast and bacteria. Enzymes also play a huge role. Enzymes exist naturally in flour and in yeast. Their job is to break down complex starches and proteins into simpler sugars that yeast and bacteria can digest.

Flour contains many types of sugars, but most are locked inside complex starch molecules. Until enzymes break those starches apart, the sugars remain trapped and unavailable.

If we rush fermentation by adding extra yeast, the dough will rise quickly. But the enzymes will not have enough time to do their work. Fewer sugars are released, and less flavor develops.

Slow fermentation allows maximum flavor to emerge. More sugars are unlocked. More subtle aromas are created. The final bread becomes richer and more complex.

Great bread is a balancing act. We need enough time to release flavor without breaking down the dough structure completely. When the balance is right, the result is extraordinary.

Fermentation Beyond Bread

Bread is my personal passion, but fermentation touches many other foods as well.

Cheese, beer, wine, spirits, sauerkraut, kimchi, and soy sauce are all products of fermentation. The same basic principles apply to all of them.

In beer making, grains are cooked into a liquid called wort. Yeast is added to consume the sugars and create alcohol and carbon dioxide. Beer is essentially liquid bread.

Cheese is created when bacteria ferment the lactose sugars in milk, producing acids and flavors over time.

Vegetables like cabbage are transformed into sauerkraut or kimchi through bacterial fermentation that changes their texture, taste, and nutritional value.

The ingredients may differ, but the process is the same. Microorganisms act on natural sugars and create new flavors and new foods.

Why Fermented Foods Are Good for You

Fermentation does more than improve flavor. It also improves nutrition.

When microorganisms ferment food, they begin the process of breaking it down. In a sense, fermentation is a form of pre digestion.

This makes fermented foods easier for our bodies to process. Nutrients become more available. Vitamins and minerals are easier to absorb. Fermented foods also support a healthy gut microbiome, which is increasingly recognized as essential to overall health.

That is why cultures all over the world have relied on fermented foods for centuries. They are not only delicious. They are also deeply nourishing.

Understanding Preferments in Baking

In modern baking, you often hear the term preferment. A preferment is simply a portion of dough that is mixed ahead of time and allowed to ferment before being added to the final dough.

The purpose of a preferment is simple. It creates better flavor in less time.

Common types of preferments include poolish, biga, and sourdough starter.

A poolish is a wet, sponge like mixture of equal parts flour and water with a tiny amount of yeast. It ferments slowly for many hours and adds complexity to the final dough.

A biga is similar, but firmer and closer in texture to regular dough.

Sourdough starter is another form of preferment, using wild yeast and bacteria instead of commercial yeast.

By adding prefermented dough to a fresh batch, you essentially give the new dough a head start. It already contains developed flavor and active microorganisms.

I like to say that a preferment allows you to quantum age your dough. What would normally take eight hours might be achieved in four.

The Big Picture

Whether we are talking about bread, beer, cheese, or vegetables, the goal is always the same.

Our job as cooks and bakers is to evoke the full potential of flavor trapped in our ingredients.

Fermentation is one of the most powerful tools we have to accomplish that goal.

When you understand how yeast, bacteria, enzymes, time, and temperature work together, you unlock an entire world of possibilities.

That is the essence of Fermentation 101.

Until next time, may your crust be crisp and your bread always rise.