Hops (Humulus lupulus)

Hops are found growing in the Cape region and are unmistakable to identify when driving past because of the way it is planted on tall vines.

Hops are the female flowers (also called seed cones or strobiles) of the hop plant, Humulus lupulus. They are used primarily as a flavoring and stability agent in beer, to which they impart a bitter, tangy flavor, though hops are also used for various purposes in other beverages and herbal medicine.

In the Middle Ages beers tended to be of a very low alcohol content (small beer) and were commonly consumed as a safer alternative to untreated water. Each village tended to have one or more small breweries with a barley field and a hop garden in close vicinity. However, the first documented use of hops in beer as a flavoring agent is from the 11th century. Before this period, brewers used a wide variety of bitter herbs and flowers, including dandelion, burdock root, marigold, horehound (the German name for horehound means "mountain hops"), ground ivy, and heather.  

Hops are used extensively in brewing for their antibacterial effect that favors the activity of brewer's yeast over less desirable microorganisms and for many purported benefits, including balancing the sweetness of the malt with bitterness, contributing a variety of desirable flavors and aromas. Historically, traditional herb combinations for beers were believed to have been abandoned when beers made with hops were noticed to be less prone to spoilage.

The first documented hop cultivation was in 736, in the Hallertau region of present-day Germany, although the first mention of the use of hops in brewing in that country was 1079.Hops were imported from France, Holland and Germany and naturally import duty was raised on those; it was not until 1524 that hops were first grown in the southeast of England (Kent) when they were introduced as an agricultural crop by Dutch farmers. Hops were then grown as far north as Aberdeen near breweries for infrastructure convenience. It was another century before hop cultivation began in the present-day United States, in 1629 by English and Dutch farmers.

Hops production is concentrated in moist temperate climates, with much of the world's production occurring near the 48th parallel north. Hop plants prefer the same soils as potatoes.  

A superstructure of overhead wires supports strings that in turn support bines.

Although hops are grown in most of the continental U.S. states and Canadian Provinces, cultivation of hops for commercial production requires a particular environment. As hops are a climbing plant, they are trained to grow up trellises made from strings or wires that support the plants and allow them significantly greater growth with the same sunlight profile. Energy that would have been required to build structural cells is also freed for crop growth.

 Hop plants are planted in rows about six to eight feet apart. Each spring the roots send forth new bines that are started up strings from the ground to an overhead trellis. The cones grow high on the bine, and in the past, these cones were picked by hand. Harvesting of hops became much more efficient with the invention of the mechanical hops separator, patented by Emil Horst in 1909.

Harvest comes near the end of summer when the bines are pulled down and the flowers are taken to a hop house or oast house for drying. Hop houses are two-story buildings, of which the upper story has a slatted floor covered with burlap. Here the flowers are poured out and raked even. A heating unit on the lower floor is used to dry the hops. When dry, the hops are moved to a press, a sturdy box with a plunger. Two long pieces of burlap are laid into the hop press at right angles, the hops are poured in and compressed into bales.

Hop cones contain different oils, such as lupulin, a yellowish, waxy substance, an oleoresin, that imparts flavor and aroma to beer. Lupulin contains lupulone and humulone, which possess antibiotic properties, suppressing bacterial growth favoring brewer's yeast to grow. After lupulin has been extracted in the brewing process the papery cones are discarded. 

Hops are also used in herbal medicine in a way similar to valerian, as a treatment for anxiety, restlessness, and insomnia. A pillow filled with hops is a popular folk remedy for sleeplessness, and animal research has shown a sedative effect. The relaxing effect of hops may be due, in part, to the specific chemical component dimethylvinyl carbinol. Hops tend to be unstable when exposed to light or air and lose their potency after a few months' storage.

Hops are of interest for hormone replacement therapy, and are used in preparations for relief of menstruation-related problems.

Info:   http://en.wikipedia.org/wiki/Hops