Yeast: Breads Best Friend

For thousands of years, people all over the world have used yeast for brewing beer and baking bread. Yeast is a fungus made up of millions of separate, single celled organisms that take in sugar and give of alcohol and carbon dioxide gas as a waste product. Yeast turns grape juice into wine, water and grain into beer, and uncooked dough into light and soft bread. Naturally yeast grows on the skins of fruit by feeding on sugars from the fruits skin.

If a mixture of yeast sugar and warm water is left to stand, bubbles of gas appear as the yeast ferments. Fermentation is a chemical process that takes place in a substance through the action of micro-organisms, as in the conversion of sugar into alcohol. Ancient Egyptians were the first to learn about fermentation, about 5000 years ago. It was probably discovered when yeast spores were blown onto dough that had been mixed and put to one side before baking. We use yeast for fermentation, as it is safe for humans.

Yeast requires a warm temperature for it to come out of hibernation. The optimum heat for yeast to grow is 38 degrees Celsius / 100 degrees Fahrenheit. Temperatures much higher will kill the yeast, as it cannot stand very high temperatures. Whether dissolving yeast in water or adding liquid to the yeast, make sure the liquid is not too warm. Lastly yeast can be used to make penicillin and other medicines. These are the many great uses of the remarkable microbe known as yeast.