Stout is a top fermented English, Scottish or Irish beer with an original gravity of about 25 percent. It is a strong beer which is almost black and with an intensely bitter taste. The strong flavour of barley is the result of the addition of roasted malt. It is a form of Porter whose roasted malt taste can vary sweet, dry to full bodied. To distinguish a Porter from a Stout, all you need do is place a full glass in front of a light. Porter will look transparent with a reddish colour while Stout will remain black and opaque. The Sweeter versions of Stout, often with a slightly aftertaste, are mainly English while dry Stouts are predominantly Scottish in origin. The sweeter Stouts were once known as Milk Stouts, but this name may no longer used because of the risk of causing confusion to the consumer, the term "Sweet Stout" is now used instead. The name 'Stout" is derived from Stout Porter, meaning strong Porter, which in the course of time was abbreviated to "Stout'. The Stout best known all over the world is the Irish Guinness Stout with its distinctive sharp, bitter taste. In Britain this type is often called "Extra Stout" or "Dry Stout". Very strong Stouts, known as "Imperial" or "Russian Stout", are also found in Britain. All Stout have their own particular bouquet. A Stout should always be poured very slowly so that the head has time to develop. It is a good idea to pause a little when pouring, in two stages the head will be denser and creamier. A Stout from the bottle will have a more solid head and a more natural taste than one delivered from a keg by compressed gas.