Beer style

What constitutes a beer style may involve provenance,[3] local tradition,[4] ingredients,[5] aroma, appearance, flavour and mouthfeel.

The work of Bedřich Hrozný on translating Assyrian merchants' tablets found in Hattusa revealed that approximately 500 years later the Hittites had over 15 different types of beer.

At the same time, brewers in Bavaria were storing beer in cool caves during the summer months to stop it from spoiling.

[1] Jackson's book had a particular influence in North America where the writer Fred Eckhardt was also starting to explore the nature of beer styles.

While North America developed beer styles into a serious study with fixed parameters of bitterness, colour, aroma, yeast, ingredients and strength, other countries continued to mainly categorise beers loosely by strength and colour, with much overlapping of naming conventions.

The aroma in a beer may be formed from the malt and other fermentables, the strength and type of hops, the alcohol, esters, and various other aromatic components that can be contributed by the yeast strain, and other elements that may derive from the water and the brewing process.

The taste characteristics of a beer may come from the type and amount of malt used, flavours imparted by the yeast, and the strength of bitterness.

Additionally, although less common, some brewers throughout the world use also alcohol by weight (abw),[9] particularly on low-point versions of popular domestic beer brands.

Before the development of modern brewing practices and the complete understanding of the biochemistry of yeast, the final abv of a beer could not be precisely controlled, making its value inconsistent and therefore unsuitable as a determinant for taxation or regulation.

For example, the distinctive flavour and aroma of Belgian Abbey ales largely result from the yeast strains used to ferment the beer.

[citation needed] There are a few modern styles, notably lambics, where spontaneous fermentation is used — that is, rather than being inoculated in a controlled fashion with a nurtured yeast, the unfermented wort is allowed to be colonised by microorganisms present in the environment.

The inclusion of some grains such as corn and rice is often viewed as making less of a flavour contribution and more of an added source of fermentable sugars.

While it is commonly held that these breweries introduced these grains to their formulas during war shortages, author Maureen Ogle states "The mythology is that these giant beer makers began adding rice and corn to their beer after World War II to water it down, but that's simply not true.

Although these men, craft brewers themselves, initially re-created the full-bodied beers of their homeland, many Americans had not developed a taste for the malt-heavy style.

"[14] Throughout history, a wide variety of flavoring agents have been added to beer to impart complexity and bitterness to the final product.

[15] In particular, two styles of beer are especially noted for their water chemistry: pale ale, for which the process of Burtonisation is widespread; and Pilsner.

Alcoholic beverages made from the fermentation of sugars derived from non-grain sources are generally not called "beer," despite being produced by the same yeast-based biochemical reaction.

Chinese jiu and Japanese sake are made using much the same process as beer with one additional step in the fermentation as well as using rice instead of primarily barley malt.

As the terminology of brewing arose before the advent of the science of microbiology, "yeast" in this context may refer not only to fungi but to some bacteria, for example Lactobacillus in Berliner Weisse.

Top-fermenting yeast typically ferments at higher temperatures 15–23 °C (59–73 °F), producing significant amounts of esters and other secondary flavours and aromas, often resembling those of apple, pear, pineapple, grass, hay, banana, plum or prune.

The cooler conditions also inhibit the natural production of esters and other byproducts, resulting in a "crisper" tasting beer.

With modern improved fermentation control, most lager breweries use only short periods of cold storage, typically 1–3 weeks.

Most of today's lager is based on the original Pilsner style, pioneered in 1842 in the city of Plzeň (German: Pilsen), in an area of the Austrian Empire now located in the Czech Republic.

The modern pale lager that developed from Pilsner is light in colour and high in forced carbonation, with an alcohol content of 3–6% by volume.

Hybrid or mixed style beers use modern techniques and materials instead of, or in addition to, traditional aspects of brewing.