How Did Hops End Up in Beer?

Photo courtesy of Walter Konig

There are some 350,000 known plant species on earth, but only one of them, Humulus lupulus, the hop plant, has become the universal flavoring agent for beer. Sure, brewers occasionally use other flavorings in their beers, such as coriander, passion fruit, or orange peel. Statistically, however, the perennial, herbaceous, creeping, climbing weed that we call hop is “it!” That begs the question: How did hops — among all those plants — rise to such an august position in the global culture of beer? Here is the story of when, where, and how that happened.

The Dawn of Beer

As best we know, our species, Homo sapiens, started fermenting beverages in the Stone Age, right after (or even before?) the so-called Neolithic Revolution, some 12 thousand years ago. For humans, that revolution marked the threshold between the fog of prehistory and the bright light of civilization. Back then, humans traded hunting and gathering ways for a better life in settlements built on agriculture, politics, administration, technology, and an economy . . . and the ferments that our ancestors started to make then are still with us today! Just as then, our modern alcoholic beverages are still based on only four starchy/sugary liquids: Saps, honey, fruit juices, and grain extracts. Tequila, for instance, is a distilled ferment of blue agave sap; mead is a fermented honey solution; wines are fermented fruit juices; and fermented extracts of grain (any grain) are beers. We do not know exactly how the ancients made their beers, but archaeological finds clearly suggest that baking and beer making were practiced side-by-side, and that bread — probably mixed with some enzyme-rich grains — was the most important ingredient in early mashes. Popular beer flavorings, especially in ancient Egypt, included dates, honey, mandrake roots, and ginger; and fermentation — and bread leavening — was obviously spontaneous, by airborne microbes.

The Botanical Origins of Hops

Humulus lupulus — Latin for the “slinking little wolf” — seems to have evolved quite apart from beer in what is now Mongolia. From there, it spread throughout the temperate zones of the northern hemisphere, roughly between 35° and 55° latitude. Botanically, hops belong to the family of Cannabinaceae, which also includes hemp and marijuana. An individual hop plant can live 20 years or longer. Today, we distinguish between five broad varieties of hops: Humulus lupulus var. lupulus, which is native to Eurasia and is the key genetic source of virtually all modern commercial hops. Then there is Humulus lupulus var. cordifolius, also known as Humulus lupulus var. Miquel Maximowicz. It is native to the temperate zones of the Far East, including Japan. Humulus lupulus var. lupuloides is native to eastern and central North America, while Humulus lupulus var. neomexicanus is native to western North America. Finally, there is Humulus lupulus var. pubescens, which is native to the midwestern and eastern United States.

All these varieties except for var. lupulus are considered “wild.” They are less important as cultivars for beer than as contributors of genetic material to the development of new commercial hop varieties. Professor Ernest Salmon at Wye College in Kent, England, for instance, bred the popular Bramling Cross, in 1927, from a female Bramling (a traditional Golding variety) and a male seedling of a wild hop — probably a lupuloides type — from the Canadian province of Manitoba. Other English crossover cultivars with wild
Manitoban genetic stock are Bullion and Brewers Gold.

Beer Flavors Before Hops

In beer’s long history, brewers have flavored their ferments with all sorts of ingredients — some harmless, some revolting, some delicious, some psychedelic, and some even poisonous. These include, in alphabetical order: Anise, artemisia, bark, bay leaf, beans, birch branches, blackthorn, blueberries, caraway, chalk, cherries, chicken blood, cinnamon, coriander, cranberries, cumin, currants, dates, eggs, elderberry, fennel, figs, gale, ginger, grains of paradise, heather flowers, ivy, juniper, lavender, liquorice, mandrake root, marjoram, meadowsweet, milfoil, mint, molasses, mugwort, mushrooms, myrtle, nettles, nuts, oak leaves, orange peel, oxen bile, passion fruit, peaches, pears, peas, pomegranate, pumpkin, reeds, rosemary, sage, strawberries, soot, yarrow, woodruff, and wormwood (vermouth) . . . and this is probably just a partial list!

In central Europe, in the first 1,000 years AD, however, beer flavorings gradually became standardized, as beer recipes were built repeatedly on particularly pleasant combinations of fresh or kiln-dried herbs and spices — known as gruit, grut, gruyt, grüssing, or graut. The exact composition of gruit mixtures varied from one region to the next, mostly because of differences in the local flora. In northwestern Europe, for instance, gruit mixes based on gale were apparently especially popular, in part because gale thrives well in the wetlands of what is now the Rhineland, Westphalia, The Netherlands, and Belgium. Farther south, on the other hand, rosemary-based mixes — often referred to in old-German texts as “Porsch” or “Porst” — were more common. In Scandinavia, beer flavors were mostly juniper-based; and in Russia, they were mostly mint-based. See the photo, above, for an idea of what gruit mix looks like.
During the High Middle Ages, in central Europe, gruit compositions even became well-guarded secrets. Gruit production became strictly regulated; and selling gruit became a highly lucrative privilege, usually granted to the church. The oldest known document referencing a gruit privilege dates from 974 AD. In it, the German Emperor Otto II granted the gruit right to a church in Liège, in present-day Belgium. It was against this socio-economic and political background of a closely held, herb-based trade in beer flavors that the humble hop flower staged its unstoppable conquest of the world’s favorite fermented beverage — first in small steps, then with a vengeance.

The Discovery of Hops by Humankind

There is quite a debate about the first mention of hops in the annals of human history. One common misperception holds that Pliny the Elder, who died in Pompeii during the Vesuvius eruption of 79 AD, is responsible for the first reference to hops — not as a flavoring for beverages but as a food (probably in the form of hop’s edible rhizomes?). “Appetitur posito vilis oliva lupo,” he is supposed to have written. This is often translated as “with hops even the humble olive is a delight.” It sounds as if the Romans already treasured the plant that has since become dear to brewers around the world.

However, if you dig deeper, there seem to be several problems with this interpretation. First, the author of this accolade to hops is probably not Pliny the Elder, but one of his contemporaries, Marcus Valerius Martialus, in his Epigrammata (epigrams), which, thanks to the wonders of, are now accessible online. In volume II, book XXVII, lines 4 to 6, Martialus states: “Hyblaeis apibus Corsica mella dabit; sed tamen et parvae nonnulla est gratia Musae; appetitur posito vilis oliva lupo.” Using my rusty Latin, this should translate literally as “While the bees of Hybla [a place in Sicily] will give you Corsican honey, nonetheless, there is [still] some small gift of the Muse: the cheap olive becomes appetizing through added hop [posito lupo].”

The second issue relates to the identity of lupus (“wolf”). Martialus probably refers to a plant commonly known in ancient Rome as lupus salictarius (“willow wolf”). Yet, the link between lupus salictarius and our Humulus lupulus was first postulated only in the Renaissance by the German herbalist Leonhart Fuchs. In his De Historia Stirpium Commentarii Insignes (Significant Commentaries on the History of Plants), published in Basel, in 1542, Fuchs postulates that lupus salictarius is “Hopffen,” which is the German word for hop, but he does not furnish any proof.

For more reliable references to “our” hops, we must skip a few centuries past the Roman Empire into the “dark” ages. A good summary of the emerging cultivation of the hop plant during that period can be found in an 1859 book by C. G. Rehlen. In Geschichte Der Handwerke Und Gewerbe (History of Craft and Trades), Rehlen points to a document from 736 AD — issued by Pippin III, the soon-to-be king of the Franks and father of Charlemagne — as the earliest post-Roman reference to what we now know as hops. That document surfaced in Geisenfeld, a village in the Hallertau region of Germany, which is now the world’s largest contiguous hop growing area. The chronologically next reference to hops, also according to C. G. Rehlen, is in Consuetudines Corbeienses (The Customs of Corbie), penned in the Picardie region of northwestern France, in the year 822, by the Benedictine Abbot Adalhard of Corbie. In it, the good abbot exempts his abbey’s millers from having to perform work in the hop gardens.

Another reference from that time, combining beer and hops for the first time in a single term, is in a collection of rules and laws called Collectio Capitularium, written between 800 and 827 AD by an advisor to Charlemagne, Abbot Angesisus of the Benedictine Abbey of Fontanelle, near Rouen, in France. Angesisus states (drum roll!) that his monastery was entitled to receive tributes in the form of “sicera humulone” — Latin for hopped strong liquor or beer — from the surrounding peasants! Should we consider Angesisus’ sicera as the true forerunner of our modern French farmhouse ale, the Bière de garde? In addition, hop gardens on monastery grounds are mentioned in documents from the Abbey of Freising near Munich, between 859 and 875 AD.

These 9th-century references to monastic hop gardens confirm what we also know from such later chronicles of monastic life as Casus sancti Galli (The Chronicles of the Abbey of Saint Gall, in present-day Switzerland), written by Abbot Ekkehard IV in the first half of the 11th century. There is no doubt that the learned Benedictine monks of central Europe started to add hops to their gruit well before the turn of the millennium. They probably discovered the virtues of hops in beer by accident as they experimented with a wide range of hitherto untested beer ingredients. Initially, the Benedictines seem to have used hops only as one of many components in their gruit. Over time, however, hops must have become an ever more important portion of monastic gruit mixes, because, within a span of about three centuries, hops gradually emerged as the sole flavoring in most central European monastery beers.

Hops Victorious

Perhaps the most consequential historical reference to hops in beer is a small passage in a book by Hildegard von Bingen, a 12th-century abbess, physician, composer, brewster, and adviser to the German Emperor Frederic Barbarossa. Her work is Liber simplicis medicinae (A Book of Simple Medicines). Hildegard wrote it in 1153, but it was first printed only in 1533 — that is, after Gutenberg — under the title of Physica (The Physical World). In it, Hildegard describes the medicinal value and beverage application of the “hoppo” plant as “a hot and dry herb, with a bit of moisture,” which “is not of much use for a human being, since it causes his melancholy to increase, gives him a sad mind, and makes his intestines heavy.” Importantly, she observes that hoppo “putredines prohibet in amaritudine sua.” One Latin expert, Pricilla Throop, translates this as “its bitterness inhibits some spoilage in beverages to which it is added making them last longer.” (See Throop’s Hildegard von Bingen’s Physica, Healing Arts Press, Rochester, Vermont, 1998, page 36.)

There you have it, for the first time ever — and from a famous brew nun, no less: Hops are great preservatives in beer! In subsequent centuries, Hildegard’s writing had an enormous influence on the thinking about hoppo; and it promoted its use especially among literate cloistered brewers and brewsters. Attesting to hop’s inroads in continental European brewing, King Louis IX of France even mandated, as early as 1268, that, in his realm and henceforth, no beer was to be brewed without hops. In 1280, Bishop Albertus Magnus, in his De vegetabilibus (About Vegetables), made the additional observation that hops loosens “thick humidities” in humans — an obvious reference to hop’s diuretic properties.

Hildegard even had several plagiarists who paraphrased her observations about hops. One such was Konrad von Megenberg, a naturalist who, between 1348 and 1350, compiled the first natural history in the German language. In this tome Buch der Natur (The Book of Nature), von Megenberg echoed Hildegard’s description of hops almost verbatim. “Humulus,” he states, “has a significant growth in length and spreads its bines over trees and walls, where it grows, like the blackberry bushes that are called Vepres in Latin. The hop flower acts warming and drying and retains this property for a long time. It also brings about a thinning of the tough juices in the human body and elsewhere.” Importantly for beer, von Megenberg asserts, just like Hildegard, that the hop plant “penetrates liquids, called Liquores in Latin, and preserves them in their power, so that they do not spoil or rot, as long as one adds only the hop blossoms to them. The hop plant itself, however, makes the belly heavy, its only good qualities being in its blossoms.” (My translation from old German.)

Not just medieval monastic brewers on the European Continent, but secular ones, too, soon switched from gruit-flavored to hop-flavored beers. Especially the mercantile brewers in such cities as Bremen, Brunswick, Einbeck, Hamburg, and Hanover in the north of Germany, who supplied beer as a trading commodity to the Hanseatic League, embraced the preserving qualities of hops and brewed their ales with nothing else. By the 14th century, therefore, flourishing and lucrative hop markets had developed in many cities, especially in Nuremberg, not far from the Hallertau in Bavaria. Hop growing and trading quickly became so profitable that the plant was dubbed “green gold.”

In Bavaria, hops finally won out completely over all other beer flavorings, because its exclusive role in brewing was elevated to a feudal edict that seems reminiscent of King Louis’ decree in France about two-and-a-half centuries earlier. To wit, in 1516, Duke Wilhelm IV of Bavaria famously mandated that “. . . henceforth, everywhere in our cities, towns and in the country no beer may contain more pieces than only barley, hops, and water.” Thus, the final death knell of brewing with gruit in Bavaria was a law that simply forbade it; and, as everybody knows, this 1516 edict is now considered the foundation of the modern German Beer Purity Law,
the Reinheitsgebot.

Hops in England

Brewers on the British Isles, on the other hand, unlike their brethren on the Continent, were much slower in adopting the use of hops as a flavoring in their ales. Only in the 16th century, after Flemish immigrant farmers had brought hop cultivation to Kent in England during the Hundred Years’ War that waged between England and France from 1337 to 1453, did English brewers gradually catch on to the “manifold vertues” (sic) of hops. This is what we learn from the botanist and herbalist John Gerard in his 1,480-page opus magnum, Herball, or Generall Historie of Plantes, published in 1597. Gerard describes the effects of the introduction of hops on English brewing on pages 884/885 (old English spelling preserved): “The manifold vertues in Hops do manifestly argue the holsomeness of Beer above Ale; for the Hops rather make it a Physical drinke to keepe the body in health than an ordinarie drinke for the quenching of our thirst . . . The buds or first sprouts which come forth in the Spring are vsed to be eaten in sallads . . . The floures are vsed to season Beere or Ale with, and too many do cause bitternesse thereof.”

In much of England, however, probably because, “too many [hops] do cause bitternesse,” many brewers continued to make ales without hops for another century or two. Just as Gerard tells us, they called their malt-based beverages without hops “ales,” while they called their brews with hops “beer.” This is obviously very different from our modern understanding of “beer” as an umbrella category for both hopped top-fermented ales and hopped bottom-fermented lagers. Interestingly, the old, hop-related distinction between ales and beers persisted in England well into the 18th century. Even the very first Dictionary of the English Language, published by Samuel Johnson, in London, in 1775, preserves the old definitions. In this seminal work, Johnson still declares that “beer” is a “liquor made from malt and hops,” while “ale” is a “liquor made by infusing malt in hot water and fermenting the liquor“ — that is, without hops . . . a distinction that was already becoming obsolete as Johnson put it into his dictionary.

Hops in the United States

In the New World, hops for beer making were introduced shortly after the arrival of the first settlers from England in the early 17th century. Instead of using native North American hops, the colonists brought with them rhizomes of hop varieties they had known back home; and they planted these wherever they went. During the colonial period, therefore, hops were cultivated up and down the entire Eastern Seaboard, from Virginia to Maine; and, as settlements moved west, so did hop farming. By the early 1800s, Upstate New York had emerged as the new country’s major hop-growing region. A few decades later, hop farms also sprang up in Wisconsin and in much of the northern Midwest. One of the classic American hop varieties that evolved in those early days was Cluster, believed to be a derivative of old, imported Dutch and English stock that had probably picked up some genetic material from native American varieties. Another strain that was perhaps also cultivated for a while in the United States was Farnham, an heirloom variety from the early 18th century, which was widely grown in and around the city of Farnham in Surrey, England. Farnham hops, however, are highly susceptible to downy mildew, which is why they have virtually disappeared from modern hop portfolios.

As the country developed farther westward, hop growing, too, moved farther west, mostly because the cold spring climate and high humidity in the Eastern and Midwestern hop-growing regions favored mildew diseases and aphid infestations. Eventually, around the beginning of the 20th century, hop cultivation had reached the Pacific Northwest. Initially, until about 1980, Northern California was a significant hop cultivation area, producing several hop varieties, including Ivanhoe, which is believed by some to be an heirloom descendant of Nugget and/or Cluster. Today, however, the American hop industry is centered almost entirely in Washington State (especially in that state’s dry Yakima Valley), Oregon, and Idaho. Each year, these three states are now responsible for more than one-third of the world’s entire hop harvest. Roughly the same amount also comes from Germany; while about one quarter comes from a small group of countries that includes China, the UK, the Czech Republic, Slovenia, Poland, Australia, New Zealand, and France.

Hop Heritage

It took the confluence of three factors in the Middle Ages — monastic experimentation; mercantile economic interests; and feudal edicts — to turn beer from a haphazardly flavored fermented malt beverage with roots dating back to the dawn of civilization into a more or less uniform drink of hops and malt. That transition occurred in central Europe, within the span of a few centuries, around the turn of the first millennium. Eventually, the perfect anti-microbial and flavor marriage between hops and malt found universal favor, first on the European Continent, next in England, then in the New World, and finally in the entire world. Only after hops had replaced all the other beer flavorings, did beer emerge as a drink that we would still recognize as such today.

Issue: January-February 2015