Hops

[5] Before this period, brewers used a "gruit", composed of a wide variety of bitter herbs and flowers, including dandelion, burdock root, marigold, horehound (the old German name for horehound, Berghopfen, means "mountain hops"), ground ivy, and heather.

[6] Early documents include mention of a hop garden in the will of Charlemagne's father, Pepin the Short.

[7] Hops are also used in brewing for their antibacterial effect over less desirable microorganisms and for purported benefits including balancing the sweetness of the malt with bitterness and a variety of flavours and aromas.

[9] In 768, hop gardens were left to the Cloister of Saint-Denis in a will of Pepin the Short, the father of Charlemagne.

[16] In England there were many complaints over the quality of imported hops, the sacks of which were often contaminated by stalks, sand or straw to increase their weight.

[17] Hop cultivation was begun in the present-day United States in 1629 by English and Dutch farmers.

[21] Important production centres today are the Hallertau in Germany,[22] the Žatec (Saaz) in the Czech Republic, the Yakima (Washington) and Willamette (Oregon) valleys, and western Canyon County, Idaho (including the communities of Parma, Wilder, Greenleaf, and Notus).

[33] Hop cones contain different oils, such as lupulin, a yellowish, waxy substance, an oleoresin, that imparts flavour and aroma to beer.

[34] Lupulin contains lupulone and humulone, which possess antibiotic properties, suppressing bacterial growth favoring brewer's yeast to grow.

The need for massed labor at harvest time meant hop-growing had a big social impact.

[35][36] The final chapters of W. Somerset Maugham's Of Human Bondage and a large part of George Orwell's A Clergyman's Daughter contain a vivid description of London families participating in this annual hops harvest.

[37] The often-appalling living conditions endured by hop pickers during the harvest became a matter of scandal across Kent and other hop-growing counties.

John Young Stratton, Rector of Ditton, Kent, began to gather support for reform, resulting in 1866 in the formation of the Society for the Employment and Improved Lodging of Hop Pickers.

[43] In addition to water, cellulose, and various proteins, the chemical composition of hops consists of compounds important for imparting character to beer.

During wort boiling, the humulones are thermally isomerized into iso-alpha acids or isohumulones, which are responsible for the bitter taste of beer.

[46] The main components of hops essential oils are terpene hydrocarbons consisting of myrcene, humulene and caryophyllene.

[50][51] The wort (sugar-rich liquid produced from malt) is boiled with hops before it is cooled down and yeast is added, to start fermentation.

[3] Flavours and aromas are described appreciatively using terms which include "grassy", "floral", "citrus", "spicy", "piney", "lemony", "grapefruit", and "earthy".

Brewers may use software tools to control the bittering levels in the boil and adjust recipes to account for a change in the hop bill or seasonal variations in the crop that may lead to the need to compensate for a difference in alpha acid contribution.

Lately the dried pucks, extracts and pellets replace whole hops in brewing processes because of efficiency and cost.

[56] Others were named for the farmer who is recognized as first cultivating them, including Goldings or Fuggles from England,[57] or by their growing habit like the Oregon Cluster.

[58][citation needed] Around 1900, a number of institutions began to experiment with breeding specific hop varieties.

Their low relative bitterness, but strong aroma, are often distinguishing characteristics of European-style lagers, such as Pilsener, Dunkel, and Oktoberfest/Märzen.

Noble hops are characterized through analysis as having an aroma quality resulting from numerous factors in the essential oil, such as an alpha:beta ratio of 1:1, low alpha-acid levels (2–5%) with a low cohumulone content, low myrcene in the hop oil, high humulene in the oil, a ratio of humulene:caryophyllene above three, and poor storability resulting in them being more prone to oxidation.

[62][64] Hops are used in herbal teas, as well as soft drinks including julmust (a carbonated beverage similar to soda that is popular in Sweden during December), Malta (a Latin American soft drink), kvass[citation needed] and hop water.

[69] A pillow filled with hops is a popular folk remedy for sleeplessness, and animal research has shown a sedative effect.

[70] The relaxing effect of hops may be due, in part, to the specific degradation product from alpha acids, 2-methyl-3-buten-2-ol, as demonstrated from nighttime consumption of non-alcoholic beer.

Hops tend to be unstable when exposed to light or air and lose their potency after a few months' storage.

[72] Hops are of interest for hormone replacement therapy and are under basic research for potential relief of menstruation-related problems.

Although few cases require medical treatment, an estimated 3% of the workers suffer some type of skin lesions on the face, hands, and legs.