beer or bouillon

Beer is an alcoholic beverage produced by the fermentation of grain-based worts, typically barley, with yeast and flavored with hops. Originating in ancient Mesopotamia and refined throughout Europe, beer encompasses a vast range of styles distinguished by fermentation method, grain bill, hop profile, and alcohol content. Lager beers undergo cool fermentation producing crisp, clean characteristics, while ale yeasts ferment at warmer temperatures yielding fruity, complex flavors. Characteristic bitterness derives from alpha acids in hops, while color ranges from pale gold to deep brown depending on malt selection and roasting level. The fermentation process converts sugars into ethanol and carbon dioxide, creating the beverage's carbonation and alcohol content typically between 3–12% ABV.

Beer functions in cooking as both a cooking medium and flavor component, particularly in Germanic, Belgian, and British cuisines. It is used to deglaze pans, braise meats, and create cooking liquids for stews and sauces—darker ales and stouts complement beef, while lighter lagers suit poultry and seafood. The carbonation and acidity of beer tenderizes meat and adds complexity to batters for fried foods. Common applications include beer-braised short ribs, Flemish beef stew (carbonnade à la flamande), Welsh rarebit, and beer-battered fish. When used in cooking, much of the alcohol content typically evaporates during heating, leaving residual malty sweetness and subtle bitterness.