HISTORY AND PRODUCTION
Known by the Romans as a culinary delicacy, and by medieval monks for their herbal properties, hops began to be grown extensively in northern Europe in the 13th and 14th centuries as a preservative and flavouring for beer. In England a thriving hop industry developed, initially in Kent where the plentiful supply of coppiced chestnut provided poles for the hop gardens and fuel for drying, and then in Herefordshire and Worcestershire which also had ideal conditions and proximity to the Midlands with its thirsty industrial workforce. Even small farms in these areas had their own hop gardens with their distinctive oast-houses.
Hops, Humulus lupulus, are in the same Cannabinaceae family as hemp and nettle – and have similar tough, fibrous stems and a rough hairiness to the stalks and leaves. Vigorous perennial plants, they thrive in rich, moist soils, establishing deep rooting systems that enable them to survive summer droughts and winter frosts. The young shoots emerge in March and twine clockwise up and around any suitable support, following the sun.
In commercial production, the strongest shoots are selected (and the rest removed) and twined up rough coir string. They grow as much as 10cm a day during May and June, reaching about 5m in height. Lateral shoots develop in July and the flowers form in August. The large hop flowers or ‘cones’ used for brewing and decoration are the fruiting bodies borne on the female plants and are composed of collections of green bracts or ‘petals’ protecting the seeds. At the base of these bracts is a yellow pollen-like substance - the plant’s essential oil (lupulin) glands that provide the bittering and preservative element used in beer-making.
Hops are ‘dioecious’ - the males and females flower on separate plants - but it is only the female plant that produces the big, soft, flowering cone that is used for beer and decoration. Male plants are sometimes planted in hop gardens to produce seeded hops.
The full length of the growing hop climbing on its string is known in Kent as a bine (or as a vine elsewhere).
Sensitivity to day length influences their viability as a horticultural crop, so even though the universal popularity of beer has made hops a world-wide commodity, the main commercial production is in areas of specific latitude: Europe, China and north-west America in the northern hemisphere, and Tasmania, parts of New Zealand, southern Australia, and the tip of South Africa in the southern hemisphere.
Needless to say, as a garden plant or for home-brewing, hops will grow happily throughout many parts of the UK if given good soil and protection from strong winds. In the wild it will reproduce readily from seed but commercially is always grown from setts or root cuttings established in the winter or early spring in frost-free ground.
In the UK, hops are harvested in the first few weeks of September. Once needing gangs of hand-pickers (a traditional working ‘holiday’ for London’s east-enders), the job is now done by machines, picking the hop flowers off the ‘bines’ to be quickly air-dried and compressed into sacks for transport to the brewers. The plants, being perennials, are then cut back to ground level and lie dormant until the spring.