Brewing started out as a cottage industry, with production taking place at home. But by the ninth century farms and monasteries began to produce beer on a larger, commercial scale. Today breweries vary greatly in size and production capacity—brewpubs function as pubs or restaurants and make their own beer to sell to customers, while major brewing companies like Anheuser-Busch can employ as many as 150,000 people. Conversely, microbreweries produce small amounts of beer and are usually independently owned. Check out our guide to breweries to find a nanobrewery in your state or to learn where to buy monk-brewed Trappist ale.