ESB

The term "bitter" has been used in England to describe pale ale since the early 19th century. Although brewers used the term "pale ale", before the introduction of pump clips, customers in pubs would ask for "bitter" to differentiate it from mild ale; by the end of the 19th century, brewers had begun to use the term as well.

During the 20th century, bitter became the most popular type of draught beer sold in British pubs and has been described as "the national drink of England". In Scotland, bitter is known as either "light" or "heavy" depending on the strength, colour and body.

Bitter is traditionally cask conditioned and either dispensed by gravity through a tap in the cask or by a beer engine at "cellar temperature" of 11 to 14 °C (52 to 57 °F). The popularity of craft brewing in North America has led to British-style bitter being brewed here since the 1980s.

The designation “Extra Special” was a way of distinguishing this style from other English bitter beers, helping to add more specificity to qualities such as hoppiness, color, and abv. An Extra Special Bitter splits the difference between “ordinary bitter” and “premium bitter” styles.