A keg is a cylindrical container typically used to store and dispense beverages, especially beer. Kegs come in various sizes, with the most common being the half-barrel, which holds about 15.5 gallons. They are usually made of stainless steel or aluminum, making them durable and resistant to corrosion. Kegs are designed to maintain the carbonation and freshness of the beverage inside. They are often equipped with a tap system that allows for easy pouring. Kegs are popular in bars, restaurants, and at events, providing a convenient way to serve drinks to large groups of people.