Beer is one of the oldest and most widely consumed alcoholic drinks in the world. It's typically made from four main ingredients: water, malted grains (usually barley), hops, and yeast.
The history of beer dates back to the early Neolithic period when cereal was first farmed. It's thought that beer was an accidental by-product of grain storage. The oldest known chemical evidence of beer dates to circa 3500–3100 BC.