Alcohol (ethanol or ethyl alcohol) is the ingredient found in beer, wine and spirits that causes drunkenness. Alcohol is formed when yeast ferments (breaks down without oxygen) the sugars in different food. For example, wine is made from the sugar in grapes, beer from the sugar in malted barley (a type of grain), cider from the sugar in apples, vodka from the sugar in potatoes, beets or other plants.