A signature bitterness, with nuances from citrusy to herbaceous to evergreen to even tropical fruit…this could be a description of an IPA beer - but is also an apt profile of the plant that gives many brews their unique flavors and aromatics: hops!  Since the advent of its use in beer brewing during the European Dark Ages, this robust vine and its curious fruits has become deeply entwined in the fabric of many cultures.  But hops also has a history of usage extending beyond its classic inclusion in beers, and it offers many benefits as an aromatic herb and essential oil.

A Sprig of Botany

Humulus lupulus, commonly called hops, is a perennial, herbaceous plant that belongs to the hemp family, Cannabaceae. Native to Europe, western Asia, and North America, it is a plant that thrives in temperate climates with moderate amounts of rainfall and sun.

Hops is a vigorous bine that that can grow to 33 feet (10 meters) tall.  A bine is a form of twining vine that has stiff, downward-facing hairs that grip surfaces and allow it to climb, instead of using tendrils or suckers to support itself. When commercially cultivated, hops are often trained to grow on strings or wires up to 25 feet (7.6 meters) tall in what is called a hopfield, hop garden, or hop yard. They are also traditionally grown on tall wooden poles spaced apart to promote good air circulation between the bines.

The vine’s Latin name reflects its exuberant and somewhat aggressive growth habit. Humulus stems from humus for ‘earth,’ likely referring to the rich and moist ground in which it likes to grow. Lupulus means ‘small wolf’ and in her herbal, Margaret Grieves shares: “As Pliny explains, when produced among osiers, it strangles them by its climbing embraces, as a wolf does a sheep. The English name "Hop" comes from the Anglo-Saxon hoppan (to climb).” (A Modern Herbal, 1931)  Osiers are basket willows (Salix viminalis), and hops growing over them was so commonly seen in some places that the vine was known as ‘willow wolf.’

As a cold-hardy perennial, hops produce new growth in the early spring, and after completing its seasonal life cycle, dies back to a rhizome in the autumn.  The leaves are dark green and palmate (palm-shaped) with three to five deep, serrated lobes. 

Hops is dioecious and has male and female flowers on separate plants which bloom in summer, usually in July or August in the northern hemisphere. The fragrant blossoms are pollinated by wind. The male flowers are catkins that lack petals. The female flowers, called strobiles, are cone-like with bright to pale green petals that envelop the fruit, which is an achene (a simple dry fruit containing one seed). These distinctive papery strobiles containing the fruit and seed are the ‘hops’ for which the plant is cultivated.  The strobiles are covered in lupulin, a sticky yellowish oleoresin that imparts the signature hops flavor and aroma to beer, herbal medicine, or other preparations.

When Humulus lupulus is commercially cultivated, only female plants are grown in hop fields to prevent pollination because pollinated seeds are undesirable for brewing beer. The female plants are propagated through cuttings, or if the vines are grown from seed, the male plants will be culled.

Hops are harvested at the end of summer. The bines are cut down from their supports and the hops strobiles are separated and immediately taken to an oast house (a building designed for kilning hops) to be dried before they begin to spoil.  Hops are spread on the upper floor of the oast house and carefully heated to dry them without volatilizing the essential oil. Once cooled, the dried hops are compressed into bales or ‘pockets.’

There are several varieties of hops, notably Humulus lupulus var. lupulus, Humulus lupulus var. cordifolius, Humulus lupulus var. lupuloides, Humulus lupulus var. neomexicanus, and Humulus lupulus var. pubescens. Within these, there are an abundance of cultivars, and each kind of hops has a slightly unique flavor and aromatic nuances alongside the classic bitterness. Different varieties and cultivars of hops are cultivated in various parts of the world to be used to brew particular styles of beer, and also as showy landscape specimens.

A Leaf Through History and Traditional Use

Though hops have been an essential part of beer brewing for hundreds of years, they had a long tradition of practical applications prior to and alongside of that usage. According to Grieves, “We find the Hop first mentioned by Pliny, who speaks of it as a garden plant among the Romans, who ate the young shoots in spring, in the same way as we do asparagus.”  She also mentions that “the leaves and flower-heads have been used to produce a fine brown dye.”  (A Modern Herbal, 1931)

The fiber in tough, flexible stems of bines was used to make a rope or cordage, as well as a coarse cloth and sometimes paper.

Hops was also used medicinally for a variety of benefits. In the twelfth century, Hildegard von Bingen included hops in her writings on natural healing and stated that it increases ‘melancholy’ or ‘black bile’ (in accordance with the doctrine of four humors current at the time) and thus recognized it as a sedative to the nervous system. It was not the herb she recommended for this purpose, but instead stated that hops usefulness was that “as a result of its own bitterness it keeps some putrefactions from drinks, to which it may be added, so that they may last so much longer.” (Physica Sacra, 1150)

Others did use hops as a calming nervine, and pillows filled with hops have long been used to promote restful sleep. Infusions of hops (teas) were given to soothe nervousness, hysteria, and delirium and to induce sleep.

Hops’ bitter qualities made it useful for aiding digestion and increasing appetite, and it was employed as a diuretic to relieve kidney and bladder troubles. It was considered cleansing to the body systems, and a tea of the strobiles, stalks, and leaves drunk several times a day was a traditional springtime tonic for sluggish livers. Hops was also esteemed for cleansing the blood and thus helping resolve problematic skin conditions.

Seventeenth-century English botanist and herbalist William Coles offers this description of hops’ wide array of virtues: "The decoction of the tops of Hops as well of the wild as the manured, is very powerfull to cleanse the Reines from Gravell, and to provoke Urine, which likewise openeth the obstructions of the Liver and Spleene, cleanseth the Blood and looseneth the belly. The roots also work the same effect, but they are hotter and not so moist as the former. As they cleanse the blood, so consequently they help to cure all manner of Scabs, Itch, and other breakings out in the body; as also all other Tetters, Ring-worms, or spreading sores, the Morphew, and all other discolourings of the Skin. The decoction of the Flowers and Tops are given with good successe to those that have drunk any deadly poyson; the same being put in baths for women to sit in, taketh away the swellings and hardnesse of the Mother; and is good for those that can very hardly make their Water because of the Strangury, or the like. Half a dram of the seed beaten to powder and taken in drink killeth the worms in the body and bringeth down Womens Courses and expelleth Urine. A Syrupe made of the juyce and Sugar, cureth the yellow Jaundise, easeth the Headach that comes of heat, and tempereth the drought of the Liver and Stomack, and therefore it is very profitable to be given in long and hot Agues that rise of Choler and Blood. The juyce of the Leaves dropped into the Eares cleanseth the corrupt sores therein, and helpeth the stench arising from the corruption of them.”  (Adam in Eden, or Nature’s Paradise of Plants, 1657)

The plant was also used in the form of a fomentation or poultice with other herbs to reduce pain and swelling, such as is described in Kings American Dispensary (1898): “Externally, in the form of a fomentation alone, or combined with boneset or other bitter herbs, hops have proved beneficial in pneumonia, pleurisy, gastritis, enteritis; also as an application to painful swellings or tumors. An ointment made by boiling 2 parts of stramonium leaves and 1 of hops, in lard, has proved an effectual application in eczema, ulcers, and painful tumors.” (Kings American Dispensary, 1898)

Additionally, Margaret Grieves mentions that “a pillow of warm Hops will often relieve toothache and earache and allay nervous irritation.”  (A Modern Herbal, 1931)

Hops likely began to be used in beer brewing around the 8th century.  There are records of hops being cultivated in the Hallertau region of Germany in 736, and King Pepin the Short's will granted hop gardens to the Cloister of Saint-Denis in 768.  Documents from a monastery in northern France indicate the usage of hops in beer in 822 CE.

Gruit, a mix of botanicals, was traditionally used to bitter and flavor beer, and common herbs for this purpose were dandelion, burdock root, marigold, horehound, myrica gale, ground ivy, and heather.  As hops began to be used, it was noticed that the hopped beers spoiled less quickly, which increased the herb’s popularity for brewing. (The lupulin in the hops strobiles has antibiotic properties, which reduces undesirable bacterial growth while favoring the growth of the brewer's yeast.) Eventually, hops largely replaced gruit in European beer production.

It is interesting to note that hops were not universally embraced as a beneficial ingredient in brewing beer.  Though it was increasingly employed on the European continent from the Middle Ages on, England was initially greatly prejudiced against hops. It is said that the planting of hops was forbidden during the reign of King Henry VI (1422-1471), and King Henry VIII (1509-1547) declared it illegal to put hops into ale because it was considered ‘a wicked weed that would spoil the taste of the drink and endanger the people.’ Though hops cultivation was allowed by Henry VIII’s successor and gradually became more popular in English brewing, even a century later English writer John Evelyn stated: “Hops transmuted our wholesome ale into beer, which doubtless much alters its constitution. This one ingredient, by some suspected not unworthily, preserves the drink indeed, but repays the pleasure in tormenting diseases and a shorter life.” (Pomona, 1670)

Curiously enough, however, one of the most iconic versions of hopped beer is an India pale ale (IPA), created for the British troops stationed in colonial India. The IPA was an alteration of a standard pale ale that had additional hops and a higher alcohol content, and stories theorize that this was either for better preservation on the long trip to India and in the hot weather of that region, and/or it was simply an attempt to keep the British Empire’s distant forces in better morale with stronger brews from home.

Humulus lupulus is indelibly associated with beer, but it holds its own as a modern herbal remedy. 

Hops is beneficial as a relaxing nervine.  One study illustrated that an extract of hops taken over a four-week period reduced stress, anxiety, and depression in young adults.  A 2018 double-blind, placebo-controlled study showed that volunteers drinking an extract of hops had fewer markers of stress during a stressful test than those taking a placebo.

As an aromatic digestive herb, hops is helpful for upper gastric digestive disorders and particularly shines for calming indigestion associated with nervous tension.

Research indicates that hops can benefit metabolic syndromes, such as insulin resistance and type 2 diabetes, because of the plant's high content of polyphenols, which can aid in reducing inflammation and cholesterol levels. Metabolic syndromes also negatively affect heart health, and a 2017 study showed that an extract of hops benefited acute endothelial function (the performance of the membranes lining the heart and blood vessels) in both smokers and non-smokers.

Hops has beneficial phytoestrogens that show promise in helping to manage menopausal symptoms. In a 2016 study, 120 women in the early stages of menopause were given either an extract of hops or a placebo for 12 weeks, the women taking the hops extract had significantly fewer hot flashes than those taking the placebo.

Vibrant, vivacious, and readily recognizable for its iconic flower cones, hops has certainly left its mark on history and culture. From its status as an essential ingredient in beers to proving its medicinal virtues through a growing base of scientific research, Humulus lupulus continues to generously offer us its uniquely aromatic benefits.

Hops has intriguing therapeutic qualities and a rich history - please let me know if you enjoyed learning about this fascinating plant!