Imperial Stout (also Double Stout, Russian Imperial Stout) is stout turned up to its most intense: thick, often syrupy body, deep dark-chocolate and dried-fruit richness, and much higher strength than a standard stout, commonly 8-12%+ ABV. Many breweries barrel-age or add coffee, vanilla, or fruit to it, layering dessert-like sweetness on top of the roast. It's the biggest, richest beer in the stout family here -- built for slow sipping rather than a full pint, in contrast to the more everyday American Stout or the lighter, sweeter Milk/Sweet Stout.