Scotch ale is the Edinburgh version of Burton Ale: dark, with a bittersweet, sometimes slightly metallic tang, and generally strong. Scotch Ale was first used as a designation for strong ales exported from Edinburgh in the 18th century. The term has become popular in the USA, where strong ales which may be available in Scotland under a different name are sold in America as "Scotch Ale", for example, Caledonian's Edinburgh Strong Ale or Edinburgh Tattoo, is sold in the USA as Edinburgh Scotch Ale. As with other examples of strong ales, such as Barley wine, these beers tend toward sweetness and a full body. Examples from the Caledonian brewery would have toffee notes from the caramelizing of the malt from the direct fired copper. This caramelizing of Caledonian's beers is popular in America and has led many American brewers to produce strong toffee sweet beers which they label as a Scotch Ale. Scotch ales are an accepted style in Belgium: Gordon's Highland Scotch Ale, with its thistle-shaped glass is a well-known example, produced by the British-connected John Martin Brewery.