ABSTRACT
Hop is indigenous to the north-temperate hemisphere. There are different wild varieties of hop plants in North America, Europe, and Japan. The geography of varieties in North America is complex. Hop vines are herbaceous, and have been known to extend more than 10 m (33 feet). The vines climb over vegetation by twining, and are assisted in holding onto surfaces by two-hooked hairs that resemble miniature grappling hooks. The annual, aboveground stem is killed by frost each year, regrowth occurring each season from perennial underground stems. The plants are male or female, pollination occurring by wind. Hop has been used through much of recorded history for culinary, medicinal, and household purposes, although it is best known as a brewing ingredient. Hops are a chief constituent of beers, which in the past have often been produced in kitchens, and not just in specialized breweries.
