A type of beer brewed from malted barley using a warm fermentation with a top-fermenting strain of brewers' yeast. The yeast ferments the beer quickly, giving it a sweet, full bodied and fruity taste. Most ales contain hops, which help preserve the beer and impart a bitter herbal flavour that balances the sweetness of the malt. Ale is typically fermented at temperatures between 15 and 24°C. At temperatures above 24°C, the yeast can produce significant amounts of esters and other secondary flavour and aroma products, and the result is often a beer with slightly fruity notes.

Historically the terms beer and ale respectively referred to drinks brewed with and without hops. Ale has usually now come to mean a bitter-tasting barley beverage fermented at room temperature. In British usage, however, the term is typically only used in compounds (such as pale ale) or as real ale (a term coined by CAMRA for a beer brewed from traditional ingredients, matured by secondary fermentation in the container from which it is dispensed and served without the use of extraneous carbon dioxide).