What pickles a cuke? Is yogurt alive? Where does Swiss cheese get its holes? How is pizza dough made?

These questions all relate to fermentation, a process people use to create and preserve many types of food.

The term "fermentation" refers to the activity of bacteria and fungi, such as yeast (which is a single-celled fungus). These microbes break complex compounds, like sugars, into simpler substances, such as carbon dioxide and alcohol. Because these simpler substances are toxic to food-spoiling microbes, they act as natural preservatives for food.

Before refrigeration, fermentation was a primary method of food preservation. Builders working on China's 1,500-mile-long Great Wall in the early part of this millennium ate cabbage fermented in wine.

Genghis Khan's forces carried pickled food with them on their invasions of eastern Europe in the 12th century. In the early 18th century, the British Navy carried pickled cabbage to provide sailors with vitamin C in order to prevent scurvy.

Kimchee is a traditional fermented cabbage dish from Korea. Koreans eat kimchee year round for the spicy taste and because it contains lots of vitamins C and B.

You may be more familiar with the traditional German pickled cabbage dish, sauerkraut, a less spicy version of kimchee.

In a bottle fermentation chamber you can pickle your own cabbage. You'll learn a lot about fermentation, and enjoy great-tasting results.