Beer is one of the oldest and most popular alcoholic beverages. Beer is brewed in almost every country in the world. Each country produces its own special types of beer. The type of beer produced by a country is based on the type of ingredients it produces. The flavor of the beer is greatly affected by the type of grain used. The most common grains used to produce beer are barley and wheat. There are about 20000 brands of beer in many different styles from ales, lagers, pilsner and stouts to bitters, cream ales and iced beers. The strength of beer may be measured by the percentage by volume of ethyl alcohol. Strong beers are in excess of 4 percent of alcohol, barley wines up to 8 to 10 percent of alcohol. Diet beers or light beers are fully fermented, low-carbohydrate beers. A Low-alcohol beer contains 0.5 to 2.0 percent alcohol and an Alcohol-Free beer contains less than 0.1 percent alcohol.