Humulus lupulus
A perennial climbing plant whose female cones flavor and preserve beer.
**Humulus lupulus**, the common hop, is a flowering perennial in the Cannabaceae family—the same group as hemp and marijuana. It is a herbaceous climber that emerges anew each spring from a cold-hardy rhizome and dies back in autumn. The plant is dioecious, meaning male and female flowers grow on separate individuals. It is native to Europe, southwestern Asia, and North America and is widely farmed for the brewing industry, as the female cone-shaped flowers—called hops—are used to preserve and flavor beer.
The plant can reach up to 10 meters (33 feet) tall and live for about 20 years. Its leaves are simple with three to five deep lobes and may be arranged opposite or alternate along the stem. Flowering is triggered by the longer days of summer, typically in July or August in the Northern Hemisphere. The fragrant flowers are wind-pollinated: male flowers lack petals, while female flowers also lack petals, with the fruit surrounded by bracts and bracteoles instead. The female flower cones (strobili) are the hops themselves. The fruit is a dry achene that does not split open when ripe; it is surrounded by sepals and bracts and dotted with glands that secrete lupulin.
The species is sometimes called a bine rather than a vine because it climbs using stiff, downward-facing hairs that provide grip and stability.
Chemically, *H. lupulus* contains myrcene, humulene, xanthohumol, myrcenol, linalool, and various tannins and resins. Hops are notable for their secondary metabolites—flavonoids, oils, and polyphenols—that shape the flavor of beer and other hop-infused products. The bitterness comes from acids made of prenylated polyketides, a class of secondary metabolites. Several genes influence taste, including O-methyltransferase 1, geranyl diphosphate synthase, and chalcone synthase. Genomic studies show that thousands of years of human selection have enhanced aroma, bitterness, and yield in cultivated varieties.
The plant’s growth, flowering, and stress responses are linked to homologous primary contigs—overlapping DNA sequences inherited from a common ancestor—that contain high sequence variation. Genes with higher divergence rates in these regions are tied to flowering, growth, and responses to both abiotic and biotic stress. These stress responses help explain differences in cultivation difficulty among geographically distinct hop varieties. Environmental stre
- Native range
- Europe, southwestern Asia, North America
Quick Facts
- Genus
- Humulus
- Species
- lupulus
Facts from the source article.
Lore & Background
Humulus lupulus is a dioecious plant, with male and female flowers on separate plants. It sends up new shoots in early spring and dies back to a cold-hardy rhizome in autumn. The plant is triggered by longer summer days to flower, usually around July or August in the Northern Hemisphere. The female flower cones, known as hops, are wind-pollinated and contain lupulin-secreting glands concentrated on the fruit, an achene. The female flowers lack petals; the fruit is surrounded by bracts and bracteoles, not tepals. The species is sometimes described as a bine rather than a vine because it has stiff downward-facing hairs that provide stability and allow it to climb.
Reader's Guide
Humulus lupulus is significant primarily for its role in the brewing industry, where its female cones provide bitterness and aroma to beer. The bitter flavors come from acids composed of prenylated polyketides, and genomic analyses show that human selection over thousands of years has enhanced aroma, bitterness, and yield. The plant also contains compounds such as xanthohumol, which is converted by large intestine bacteria into the phytoestrogen 8-prenylnaringenin, and its extracts have antimicrobial and sleep-aiding properties. Hops share a family with Cannabis sativa, diverging over 20 million years ago, with about 73% genomic overlap, including the cannabidiolic acid synthase gene. The genome of H. lupulus is large and complex, similar in size to the human genome, making genetic study challenging. Climate change may threaten hop cultivation by altering the transcriptome and reducing yields. The plant is also known for causing dermatitis in about 1 in 30 people who handle it.
Did You Know?
- The specific epithet 'lupulus' is Latin for 'small wolf,' referring to the plant's tendency to strangle other plants like a wolf does a sheep.
- The English word 'hop' is derived from the Middle Dutch word 'hoppe.'
- Hops and Cannabis sativa are estimated to have approximately a 73% overlap in genomic content.
- Extracts of bitter alpha-acids in hops have been shown to decrease nocturnal activity, acting as a sleep aid.
Frequently Asked Questions
What is Humulus lupulus?
It is the common hop, a perennial climbing vine in the Cannabaceae family that dies back each autumn and regrows from an underground rhizome every spring. Its cone-shaped female flowers are the ingredient brewers simply call "hops."
What role does Humulus lupulus play in brewing?
The female flower cones are added to beer to contribute bitterness, aroma, and natural preservation. Without them, most modern lagers and ales would not exist in their current form.
How big does a Humulus lupulus plant get?
A single vine can climb up to roughly 10 metres (about 33 feet) tall, and a well-established plant can persist for around 20 years before it eventually dies out.
Where is Humulus lupulus originally from?
It is native to Europe, southwestern Asia, and North America, though it is now cultivated on a massive scale worldwide to feed the global beer industry.
Is Humulus lupulus related to cannabis?
Yes—it belongs to the Cannabaceae family, which also includes hemp and marijuana, but the hop itself is entirely non-psychoactive and is grown purely for its aromatic, cone-shaped flowers.
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