The type of alcohol found in alcoholic beverages is known as ethanol—produced by yeast through the process known as alcoholic fermentation. During the breakdown of glucose to harvest energy, cells generate ethanol as a way to recycle a molecule that is crucial to their metabolism. Interestingly, yeast can only survive in media (like beer or wine) that contains less than 10 percent alcohol by volume. (For more about yeast, see the chapter “Fungi.”) This means that beverages with an alcohol content greater than 10 percent have been fortified with additional alcohol or have been distilled. (Distillation involves the boiling off and then the condensation of the ethanol, which evaporates at a lower temperature than water.)