to create a creamy texture with a long-lasting head. Some canned and bottled stouts include a special device called a "widget" to nitrogenate the beer in the container to replicate the experience of the keg varieties. Gallery of Irish stouts Porter There were no differences between stout and porter historically, though there had been a tendency for breweries to differentiate the strengths of their beers with the words "extra", "double" and "stout". The term stout was initially used to indicate a stronger porter than other porters from a brewery. Oatmeal stout Oatmeal stout is a stout with a proportion of oats, normally a maximum of 30%, added during the brewing process. Even though a larger proportion of oats in beer can lead to a bitter or astringent taste, during the medieval period in Europe, oats were a common ingredient in ale, and proportions up to 35% were standard. Despite some areas of Europe, such as Norway, still clinging to the use of oats in brewing until the early part of the 20th century, the practice had largely died out by the 16th century, so much so that in 1513 Tudor sailors refused to drink oat beer offered to them because of the bitter flavour. There was a revival of interest in using oats during the end of the 19th century, when (supposedly) restorative, nourishing and invalid beers, such as the later milk stout, were popular, because of the association of porridge with health. Maclay of Alloa produced an Original Oatmalt Stout in 1895 that used 70% "oatmalt", and a 63/- Oatmeal Stout in 1909, which used 30% "flaked (porridge) oats". In the 20th century, many oatmeal stouts contained only a minimal amount of oats. For example, in 1936 Barclay Perkins Oatmeal Stout used only 0.5% oats. As the oatmeal stout was parti-gyled with their porter and standard stout, these two also contained the same proportion of oats. (Parti-gyle brewing involves blending the worts drawn from multiple mashes or sparges after the boil to produces beers of different gravities.) The name seems to have been a marketing device more than anything else. In the 1920s and 1930s Whitbread's London Stout and Oatmeal Stout were identical, just packaged differently. The amount of oats Whitbread used was minimal, again around 0.5%. With such a small quantity of oats used, it could only have had little impact on the flavour or texture of these