The alcohol found in wine, beer and hard liquor is really ethanol, the same stuff that powers alternative-fuel vehicles. To make ethanol (alcohol), all you need is a sugary (high carbohydrate) feedstock like grapes, corn or malted barley, plus water and yeast. Yeasts are microscopic organisms that metabolise the carbohydrates in the feedstock and produce two by-products: ethanol and carbon dioxide. The carbon dioxide produced by yeast is what makes bread dough rise. To encourage ethanol production, brewers cover vats of fermenting material and allow only the carbon dioxide to escape. Wine, beer and other fermented brews – like the grain mash that’s used to make whisky – can be distilled to concentrate their alcohol content, creating more potent spirits like gin, vodka, brandy and rum.