Cannabaceae (Cannabinaceae; Hemp Family); sometimes placed in the Moraceae Family (cf. Zander 1994, 315*)
Forms and Subspecies
There is only one species,164 a wild form with different varieties, but numerous cultivars (Edwardson 1952; Small 1978). The cultivars were formerly described as unique species (see “Synonyms”); they are now regarded as varieties. Today, morphological differences are the basis for recognizing five varieties: Humulus lupulus var. cordifolius (Miq.) Maxim in Franch. et Sav., Humulus lupulus var. lupuloides E. Small, Humulus lupulus var. lupulus L., Humulus lupulus var. neomexicanus Nelson et Cockerell, and Humulus lupulus var. pubescens E. Small. The most famous of the cultivated sorts are Saazer hops (Chechnya, Bohemia), Nittelfrüh hops (Bavaria), Tettnanger hops (Switzerland), Fuggles hops (England), Goldings hops (England), and Cascade hops (United States).
Cannabis lupulus (L.) Scopoli
Humulus americanus Nutt. (= Humulus lupulus var. lupuloides E. Small)
Humulus cordifolius Miq. (= Humulus lupulus var. cordifolius [Miq.] Maxim in Franch. et Sav.)
Humulus lupulus var. brachystachyus Zapalowics
Humulus neomexicanus (Nelson et Cockerell) Rydberg (= Humulus lupulus var. neomexicanus Nelson et Cockerell) Humulus volubilis Salisb.
Humulus vulgaris Gilib.
Humulus yunnanensis Hu (may be a distinct species)
Lupulus communis Gaertn.
Lupulus humulus Mill.
Lupulus scandens Lam.
Bierhopfen, gemeiner hopfen, hop, hopf, hopfen, hoppen, hoppho, hops, houblon, hupfen, lupolo, luppolo, lupulo, vigne du nord
Pliny appears to have been the first to mention hops; Dioscorides was not yet aware of the plant. It is first referred to by name in medieval manuscripts, which also make mention of homularien, “hops gardens,” a reference not to cultivated fields but to large wild occurrences of the plant (DeLyser and Kasper 1994, 166). Hildegard von Bingen was the first to more precisely describe the plant’s psychoactive effects and its use as a preservative (in beer). Hops also appears in the works of all of the fathers of botany and was botanically described by Linnaeus.
Because no fossil precursors have been found, the phylogeny of the plant is entirely unknown. Hops is the closest relative of hemp (Cannabis indica, Cannabis sativa).
Today, hops is the most commonly used beer additive. This use was invented toward the end of the Middle Ages by Christian monks, who had a great interest in the anaphrodisiac qualities of hops flowers. Abbé Adalhard, in the Statutae abbatiae corbej (822 C.E.), was the first to document the use of hops in beer. However, the use of hops as a beer additive did not become commonplace until the sixteenth century, when the Bavarian Purity Law—the first German drug law—was promulgated (DeLyser and Kasper 1994, 168; Wilson 1975).
Hops appears to have originated in northern Eurasia. Beer-loving humans spread the plant, which is now found throughout the world. Its presence in central Europe has been documented to as early as the eighth century. Today, hops is cultivated in all of the world’s temperate zones. One of the most important areas of commercial cultivation is in Tasmania (Pearce 1976), which has the best air in the world, copious rainfall, and now—unfortunately—an overabundance of UV radiation (harmful to humans).
In central Europe, wild hops can be found growing in lowland forests and fens, on the sides of paths, and in hedges.
Female plants only are grown vegetatively, i.e., through clones and cuttings (Gross 1900).
Hops is a 6- to 8-meter-long (in cultivation, it can grow up to 12 meters), perennial, dextrorotatory, twisting climber with three to five lobed, opposite leaves.
The plant is dioecious; the male flower is paniculate, the female a so-called strobile that becomes the fruit cone (hop cone or achene). The flowering period is between July and August, and the fruit cones ripen from September to October (in Australia and Tasmania, the ripening period is from April to May).
The stems are a source of fiber (similar to that of hemp, but not as durable). In former times, the fiber was made into linen cloth (DeLyser and Kasper 1994).
Today, the primary use of the sedative hops plant is as an additive to beer. (Woodcut from Tabernaemontanus, Neu Vollkommen Kräuter-Buch, 1731)
—Female inflorescences (strobiles), also known as hops flowers (stroboli lupuli, lupuli stroboli) or hop glands (lupuli glandula)
Because the active constituents in the dried plant material are continuously broken down by oxidation, flowers that are more than one year old should not be used. The flowers must be harvested before they lose their glandular leaves.
Preparation and Dosage
A calming hops tea can be brewed with two heaping teaspoons of hops flowers and 1/4 liter of boiling water. To increase the sedative effects, valerian (Valeriana officinalis L.) may be added. Many breweries produce heavily hopped beer (pilseners), most of which have a very bitter taste and also are useful as soporific drinks.
Hops—the “soul of Christian beer”—was first ingested “ritually” by monks to suppress their natural urges. These chaste men drank huge quantities of beer so that they could resist the temptations of the devil, i.e., their own desires.
However, hops has never played any particular role as a true ritual plant. In recent centuries, hops flowers have occasionally found use as an incense or an ingredient in incense blends. The plant was assigned to the planet Mars (Culpeper) and the element water.
The Omaha Indian tribe had a society of buffalo doctors (te’ithaethe) composed of men and women to whom the buffalo had appeared in a dream. The members of this society were specialized in the treatment of wounds. Their most important medicine consisted of wild hops, the root of the nightshade Physalis heterophylla Nees., and American sweet cicely, Osmorhiza longistylis (Torr.) DC. They chewed these three ingredients and then spat them with some water onto the wounded region (Kindscher 1992, 269*).
Hops and the harvesting of hops are the subjects of many paintings and illustrations from the nineteenth and early twentieth centuries (e.g., The Hops Harvest, by William Henry Pyne, and The Hops Pluckers, by H. Stelzer).
Hops and hops extracts are used as sedatives in both folk medicine and biological medicine. The German Federal Health Office has recommended the use of hops tea as a sedative for unease, anxiety, and sleep disorders.
Hops pillows are used in aromatherapy to promote calm and to relieve difficulty in sleeping. These pillows have been known since at least the eighteenth century and were used in cases in which “opium had already failed” (DeLyser and Kasper 1994, 167).
In homeopathy, the agent Humulus lupulus is used primarily as a sedative.
Hop flowers contain 15 to 30% resin, the bitter acids humulone and lupulone (and their auto-oxidation products), and an essential oil with mono- and sesquiterpenes (2-methyl-3-buten-2-ol, β-caryophyllene, farnesene, humulene, 2-methylisobutyrate, methyl-n-octylketone, myrcene, post-humulene-1, posthumulene-2), along with minerals, flavonoids, chalcones, polyphenoles, and catechines.
The yellow hops granules, which contain the bitter substance lupulone, are found in hops flowers. Lupulone, which has antibiotic properties, gives beer its characteristic bitterness. It has calming effects on humans and inhibits premature ejaculation. Also present are enzyme-inhibiting polyphenoles (Williams and Menary 1988).
Numerous chemical races (chemocultivars, chemovarieties) have been described for hops. These vary both quantitatively and qualitatively in their concentrations of bitter substances and essential oils (Wohlfart 1993, 448).
The leaves contain camphor oil, quercetin and quercetin glycosides (rutin; cf. Psidium guajava), proanthocyanidins (procyanidin, prodelphini-dine), ascorbic acid, and quebrachitol (Wohlfart 1993, 448).
Because hops is very closely related to hemp (Cannabis sativa), attempts have been made to find cannabinoids (THC) in the former. To date, none has been detected.
Hops produces a yellow coloring agent that was once used in dyeing
Hops is a sedative and also has been characterized as a “mild hypnotic” (Roth et al. 1994, 406*; Lee et al. 1993). It has pronounced sedative effects, especially when used in combination with valerian (Valeriana officinalis), and is effective in treating sleep disorders and withdrawal from diazepam addiction (Brattström 1996).
The bitter substances have antibacterial, antimycotic, spasmolytic, and estrogenic effects. Because of the estrogenic properties of hops, chronic beer consumption can result in a feminization of the male body. This can be expressed in morphological changes, e.g., the development of what are known as “beer breasts.” The effects of hops are not affected by alcohol (Brattström 1996). Some of the narcotic effects of the plant may be due to the presence of quercetin (cf. Psidium guajava).
A female hops plant (Humulus lupulus) with its characteristic flowers (hops cones).
The hop is warm and dry, and it has some moisture, and it is not very suitable for the use of man, for it causes melancholy to increase in man, and it makes the mind of man sorrowful, and it burdens his intestines. But with its bitterness, it keeps certain corruptions away from the beverages to which it is added, so that they are that much more imperishable.”
HILDEGARD VON BINGEN
Fresh hops cones may irritate the skin (i.e., provoke allergic reactions) and produce a dermatitis known as hops pluckers’ disease. Hops eye, a kind of conjunctivitis, can also occur (Wohlfart 1993, 453 ff.)
Side effects (apart from the allergic reactions) and interactions are unknown.
Commercial Forms and Regulations
All hops drugs and preparations, including homeopathic preparations (Humulus lupulus hom. HAB1, Humulus lupulus hom. PFX, Lupulus, Lupulinum hom. HPUS88), are available without restriction.
The Japanese hops (Humulus japonicus) is not suited for use as a beer additive, although it may have psychoactive properties. (Photographed in Songlisan, South Korea)
See also the entries for Cannabis x and hybrids and beer.
Brattström, A. 1996. Wirksamkeitsnachweis von Phytopharmaka am Beispiel einer Hopfen-Baldrian-Kombination. Forschende Komplementärmedizin 3 (4): 188–95.
DeLyser, D. Y., and W. J. Kasper. 1994. Hopped beer: The case for cultivation. Economic Botany 48 (2): 166–70.
Edwardson, J. R. 1952. Hops—their botany, history, production, and utilization. Economic Botany 6:160–75.
Gross, E. 1900. Hops: In their botanical, agricultural and technical aspect and as an article of commerce. London: Scott, Greenwood and Co.
Lee, K. M., J. S. Jung, D. K. Song, M. Kräuter, and Y. H. Kim. 1993. Effects of Humulus lupulus extract on the central nervous system in mice. Planta Medica 59 suppl.: A691.
Pahlow, Mannfried. 1985. Hopfen und Baldrian. Stuttgart: J. F. Steinkopf.
Pearce, H. R. 1976. The hop industry in Australia. Melbourne: Melbourne University Press.
Simmonds, P. L. 1877. Hops: Their cultivation, commerce, and uses in various countries. London: E. and F. N. Spon.
Small, E. 1980. The relationships of hop cultivars and wild variants of Humulus lupulus. Canadian Journal of Botany 58 (6): 676–86.
Stevens, R. 1967. The chemistry of hop constituents. Chemical Review 67:19–71.
Williams, Elizabeth A., and Robert C. Menary. 1988. Polyphenolic inhibitors of alpha-acid oxidase activity. Phytochemistry 27 (1): 35–39.
Wilson, D. G. 1975. Plant remains from the Graveney boat and the early history of Humulus lupulus L. in Western Europe. New Phytologist 75:627–48.
Wohlfart, Rainer. 1993. Humulus. In Hagers Handbuch der pharmazeutischen Praxis, 5th ed., 5:447–58. Berlin: Springer.
Zuurbier, K. W. M., S. Y. Fung, J. J. C. Scheffer, and R. Verpoorte. 1993. Possible involvement of chalcone synthase in the biosynthesis of bitter acids in Humulus lupulus. Planta Medica 59 suppl.: A588.