Guinness (pronounced /ˈɡɪnɪs/ GIN-is) is a popular Irish dry stout that originated in the brewery of Arthur Guinness (1725–1803) at St. James's Gate, Dublin. Guinness is directly descended from the porter style that originated in London in the early 18th century and is one of the most successful beer brands worldwide. A distinctive feature is the burnt flavour which is derived from the use of roasted malted barley (though this is a relatively modern development since it did not become a part of the grist until well into the 20th century). For many years a portion of aged brew was blended with freshly brewed product to give a sharp lactic flavour (which was a characteristic of the original Porter). Although the palate of Guinness still features a characteristic "tang", the company has refused to confirm whether this type of blending still occurs. The thick creamy head is the result of the beer being mixed with nitrogen when being poured. (Source: Wikipedia) http://www.guinness.com/