Beer style
Beer styles differentiate and categorise beers by colour, flavour, strength, ingredients, production method, recipe, history, or origin.
The modern concept of beer styles is largely based on the work of writer Michael Jackson in his 1977 book The World Guide To Beer. In 1989, Fred Eckhardt furthered Jackson's work publishing The Essentials of Beer Style. Although the systematic study of beer styles is a modern phenomenon, the practice of distinguishing between different varieties of beer is ancient, dating to at least 2000 BC.
What constitutes a beer style may involve provenance, local tradition, ingredients, aroma, appearance, flavour and mouthfeel. The flavour may include the degree of bitterness of a beer due to bittering agents such as hops, roasted barley, or herbs; and the sweetness from the sugar present in the beer.
Types
Many beer styles are classified as one of two main types, ales and lagers, though certain styles may not be easily sorted into either category. Beers classified as ales are typically made with yeasts that ferment at warmer temperatures, usually between, and form a layer of foam on the surface of the fermenting beer. Thus, they are called top-fermenting yeasts. Lagers utilise yeasts that ferment at considerably lower temperatures, around, and can process raffinose, a complex sugar created during fermentation. These yeasts collect at the bottom of the fermenting beer and are therefore referred to as bottom-fermenting yeasts. Lagers constitute the majority of beers in production today.Some beers are spontaneously fermented from wild yeasts, for example the lambic beers of Belgium.
Additional markers are applied across styles. The terms "imperial" or "double" are used interchangeably for a higher-alcohol version of a particular style. Originally applied to imperial stouts, a high-alcohol style of stout brewed in England for export to Imperial Russia, the term “imperial” can now be applied to any style name to indicate a higher alcohol content. "Double", meaning the same thing, originated with the dubbel style of Trappist beers in the 19th century. Even higher alcohol-content beers can be labeled "triple" or even "quad". Lower-than-standard alcohol content is often indicated by the term "session". For example, while India pale ales often have alcohol content around 6–7% abv, a "session India pale ale" will often have alcohol content below 5%.
Barrel-aged beer is aged in wood barrels. Sour beer is made with additional microorganisms such as Brettanomyces or Lactobacillus.
History of beer styles
Styles of beer go back at least to Mesopotamia. The Alulu Tablet, a Sumerian receipt for "best" ale written in Cuneiform found in Ur, suggests that even in 2050 BC there was a differentiation between at least two different types or qualities of ale. 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.Documents reveal comments on different local brewing methods or ingredients. Pliny the Elder in his Naturalis Historia wrote about Celts brewing ale "in Gaul and Spain in a number of different ways, and under a number of different names; although the principle is the same." Anglo-Saxon laws reveal they identified three different ales, while the Normans mention cervisae and plena cervisia in the Domesday Book.
By the 15th century brewers in Germany and the Low Countries were using hops to flavour and preserve their ale; this new style of ale was called beer. When this trend came to Britain and brewers of beer in Southwark, London, started to take sales away from the traditional brewers of unhopped ale, there were complaints and protests. Laws were passed favouring either beer or ale for a number of years, until hopped beer became the standard style throughout Europe. At the same time, brewers in Bavaria were storing beer in cool caves during the summer months to stop it from spoiling. The type of beer they stored in this manner became known as lager from the German word lagern, meaning "to store".
Although beers using naturally dried malt would have been pale-coloured, by the 17th century most malts in Europe would have been dried over a fire, resulting in a dark-coloured beer. When coke started to be used for roasting malt in 1642, the resulting lighter coloured beers became very popular. By 1703 the term pale ale was starting to be used, though the beer it described was a lightly hopped ale, very different from more bitter modern versions.
However, despite an awareness by commentators, law-makers, and brewers that there were different styles of beer, it was not until Michael Jackson's World Guide To Beer was published in 1977 that there was an attempt to group and compare beers from around the world. 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. The wine importing company Merchant du Vin switched to importing beers mentioned in Jackson's book. Small brewers started up, producing copies and interpretations of the beer styles Jackson described.
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.
Elements of beer style
Beers may be categorised based on a number of factors.Appearance
The visual characteristics that may be observed in a beer are colour, clarity, and nature of the head. Colour is usually imparted by the malts used, notably the adjunct malts added to darker beers, though other ingredients may contribute to the colour of some styles such as fruit beers. Colour intensity can be measured by systems such as EBC, SRM or Lovibond, but this information is rarely given to the public.Many beers are transparent, but some beers, such as hefeweizen, may be cloudy due to the presence of yeast making them translucent. A third variety is the opaque or near-opaque colour that exists with stouts, porters, schwarzbiers and other deeply coloured styles. Thickness and retention of the head and the lace it can leave on the glass, are also factors in a beer's appearance.
Aroma
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.Flavour
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. Bitterness can be measured on an International Bitterness Units scale, and in North America a number of brewers record the bitterness on this scale as IBUs.Mouthfeel
The feel of a beer in the mouth, both from thickness of the liquid and from carbonation, may also be considered as part of a beer's style. A more dextrinous beer feels thicker in the mouth. The level of carbonation varies from one beer style to another. For some beers it may give the beer a thick and creamy feel, while for others it contributes a prickly sensation.Strength
The strength of beer is a general term for the amount of alcohol present. It can be quantified either indirectly by measurement of specific gravity, or more directly by other methods.Gravity
Measurement of the specific gravity of the beer has been used to estimate the strength of beer by measuring its density. Several different scales have been used for the measurement of gravity, including the Plato, Baumé, Balling, and Brix scales, with the Plato scale being the most common modern measure.This approach relies on the fact that dissolved sugars and alcohol each affect the density of beer differently. Since sugars are converted to alcohol during the process of fermentation, gravity can be used to estimate the final alcohol. In beer brewing, a distinction is made between the original gravity, the gravity of the wort before fermentation has begun, and the final gravity of the product when fermentation has completed. Since the concentration of sugars is directly proportional to the gravity, the original gravity gives a brewer an idea of the potential alcoholic strength of the final product. After fermentation, the differences between the final and original gravities indicate the amount of sugar converted into alcohol, allowing the concentration of alcoholic strength to be calculated.
The original gravity of a beer was the basis for determining taxation in both the UK and Ireland from 1880 until the late 20th century, and a legacy of that system remains in the largely arbitrary division of bitter into "bitter", "best bitter", and "special bitter" substyles. In continental Europe, the density of a beer in degrees Plato is sometimes used by a brewery to distinguish a particular beer produced in a line. For example, Rochefort Brewery produces three beers, all dissimilar in colour, flavour, and aroma; and sells them as Rochefort 6, Rochefort 8, and Rochefort 10, the numbers referring to the original gravities of the beers. Westvleteren Brewery, meanwhile, produces three beers and calls them Blonde, 8, and 12.
Alcohol concentration
Modern classification of the strength of alcoholic beverages for the purposes of taxation and regulation typically discriminates according to the percentage of alcohol by volume, generally abbreviated as abv. Additionally, although less common, some brewers throughout the world use also alcohol by weight, particularly on low-point versions of popular domestic beer brands. At the relatively low alcohol concentrations of beer, the alcohol percentage by weight is roughly 4/5 of the abv, but this becomes increasingly inaccurate as the alcohol concentration increases.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. Contemporarily, though, abv is often used to determine the duty on beer and cider, and sales of beer and cider above a certain abv are sometimes restricted or prohibited. For example, in Texas, beers below 4% abv cannot be sold as stout regardless of other stylistic considerations.