Imperial stout, also known as "Russian Imperial stout", is a strong dark beer in the style that was brewed in the 18th century byThrale's Anchor Breweryin London for export to the court ofCatherine II of Russia.In 1781 the brewery changed hands and the beer became known as "Barclay Perkins Imperial Brown Stout".It was shipped toRussiabyAlbert von Le Coqwho was awarded a Russianroyal warrantwhich entitled him to use the name "Imperial".A recipe from 1856 shows it had anoriginal gravityof 1.107 (almost certainly over 10% abv) and over 10poundsof hops to thebarrel. When Barclay's brewery was taken over byCouragein 1955, the beer was renamed "Courage Imperial Russian Stout" and it was brewed sporadically until 1993.
In Canada, Imperial Stout was produced inPrince Albertfirst by Fritz Sick, and then byMolsonfollowing a 1958 takeover.Denmark's Wiibroe Brewery launched its 8.2 percent Imperial Stout in 1930.The first brewery to brew an Imperial Stout in the United States was Bert Grant'sYakima Brewing.
Imperial stouts have a high alcohol content, usually over 9%abv, and are among the darkest available beer styles.Samuel Smith'sbrewed a version for export to theUnited Statesin the early 1980s, and today imperial stout is among the most popular beer styles with U.S.craft brewers.American interpretations of the style often include ingredients such as vanilla beans, chili powder, maple syrup, coffee, and marshmallows. Many areaged in bourbon barrelsto add additional layers of flavour.The word "Imperial" is now commonly added to other beer styles to denote a stronger version, henceImperial IPAs,Imperial pilsnersetc.