Home > Hop (plant)
Note: hops redirects here. See also: Hops (restaurant) .
Hops are the female flowers of the Humulus lupulus, or hop, vine used as a flavor and stability agent in beer. The hop plant is technically a bine; unlike a vine which uses tendrils, suckers, and other appendages to aid in climbing, bines have stout stems with stiff hairs to climb.
The hop plant grows from a cold-hardy perennial rhizome. Shoots emerge in early spring with the first spring flowers. Hop shoots grow very rapidly and at the peak of growth can grow upwards of a foot (300 mm) a week. Hop bines climb by wrapping clock-wise around anything within reach. Typically individual bines grow between 18 and 30 feet (5.5 to 9 metres) depending on what is available to grow on. When the hop bines run out of material to climb horizontal shoots grow from between the leaves of the main stem and the stem.
Hop acids have a mild antibioticAn antibiotic is a drug that kills or slows the growth of bacteria. Antibiotics are one class of "antimicrobials", a larger group which also includes anti-viral, anti-fungal, and anti-parasitic drugs. They are relatively harmless to the host, and therefor effect against Gram-positiveGram-positive bacteria are those that are stained dark blue or violet by gram staining, in contrast to gram-negative bacteria, which are not effected by the stain. The stain is caused by a high amount of peptidoglycan in the cell wall, which typically lac bacteria which favors the exclusive activity of brewing yeast in the fermentation of beer. The flavor imparted by hops varies greatly by variety and use; hops boiled with the beer ("bittering hops") produce a bitterness while hops added to beer later impart some degree of "hop flavor" (final 10 minutes of boil) and "hop aroma" (final 3 minutes, or less of boil ) and a lesser degree of bitterness. Adding hops after the boil, a process known as "dry hopping," adds very little bitterness. The degree of bitterness imparted by hops depends on the degree to which otherwise insoluble alpha acids (AAs) are isomerIn chemistry, isomers are molecules with the same chemical formula and often with the same kinds of bonds between atoms, but in which the atoms are arranged differently. Many isomers share similar if not identical properties in most chemical contexts.ized during the boil. Unboiled hops are only mildly bitterBitter is one of the five basic tastes. Many people find bitter tastes unpleasant; many alkaloids taste bitter, and evolutionary biologists have suggested that a distaste for bitter things evolved to enable people to avoid poisoning. The bitterest substan. The bitterness impact of a given amount of hops is specified in International Bitterness UnitsThe hoppy character of beer is measured by the International Bitterness Units scale or IBU scale for short. An IBU is one part per million of isohumulone. The higher number, the greater the bitterness. A light American lager might be as low as 5 on the IB.
Noble hops are low in bitterness and high in aroma, and traditionally consist of four central European varieties:
- Hallertauer Mittelfrueh
- Tettnanger
- Spalter and
- Saaz.
They contain high amounts of the hop oil humulene and low amounts of alpha acid cohumulone , and impart an elegant, refined taste and aroma to beers containing them. They are traditionally an important element of true Pilsener.
Other hops with high ratios of hop oil to bittering acids can be used as equivalents. Examples of such hops include Fuggle, Golding, Hersbruck and Styrian.
Flavors and aromas are described appreciatively using terms including: grassy, floral, citrusy, and spicy. Most of the common commercial lager-style beers have fairly low hop influence, true Pilseners should have noticeable noble hop aroma, while certain ales can have high levels of bitterness.
The first documented instance of hop cultivation is 736 A.D. in the Hallertau region of present-day Germany but the first mention of the use of hops in brewing is in 1079 A.D. Hops were introduced to British beers in the early 1500s and hop cultivation was begun in the United States in 1629.
In Britain today, the principal centres for production are in Kent (whence come Kent Golding hops) and Worcestershire. The principal centre for production in the United States is Washington state.
