Properties of the hop plant
The virtues of lupulin powder
Medicinal properties of the hop
Author and sources
Properties of the hop plant
The hop (Humulus lupulus L.) is a dioecious plant of the family Cannab(in)aceae, to which hemp (Cannabis sativa L.) also belongs. Only the hop cones of the female hop plant are used as essential raw material for beer. Female hop cones contain lupulin powder, rich in compounds that give beer a bitter taste whilst also acting as natural preservatives.
The hop is a sensitive plant and does not flourish everywhere. Hops have particular requirements regarding intensity and wavelength distribution of sunlight, and commercial hop cultivation is limited to areas between the 35th and the 55th parallels. The main hop-growing regions in the world are Hallertau (Bavaria), Yakima (Washington), Kent (UK) and Bohemia (Czech Republic) in the Northern Hemisphere and Australia and New Zealand in the Southern Hemisphere. In total, approximately 80 000 tons of hops are harvested from some 135 850 acres. There are about 40 different varieties (cultivars) of Humulus lupulus from which the brewer can choose, according to the style of beer he wishes to brew.
A hop plant has 12 to 20 years of productive life. The above-ground parts of the plant die back during the Winter, but the root stocks survive. In good conditions, a root stock can grow about four and a half feet high and six feet wide. By early Spring, shoots appear on the root stocks. The young hop shoots are a culinary delight! In commercially grown hop plants, shoots are wound around wires in clockwise direction only, and are further secured to an elaborate network of posts and poles to train the upwards growth of the plant. A hop plant can reach a final height of 24, 25 feet.
Hop cultivation in the Northern Hemisphere is situated mainly between April and July. In favourable conditions hop vines can grow by as much as 35 inches a day. A hop plant can attain an average growth rate of 4 inches a day, making the hop one of the fastest-growing plants in the vegetable kingdom. Commercial hop plantations are frequently treated against fungi (mildew, white rot) and pests (lice, red mites). At present – unfortunately – there are no hop varieties that are resistant to predators.
Once the hop plant is fully grown (late June, early July), it begins to flower. After about a month the female flowers develop into the hop “cones”, while the male flowers simply wither away. It is legally forbidden to grow male and female hop plants together in the same field, because fertilized hops are of inferior brewing quality. The presence of fats and oils in the seeds prevents flocculation, and the beer cannot keep its froth.
Ripe hop cones are harvested in late August, early September. The hop cones used to be picked by hand, but now this is done by machines. The machine cuts the vines in the hop field and the hop cones are immediately separated from the vines and leaves in the hop house. The cones are then carefully dried with hot air blowers at moderate temperatures (below 65°C). After all, the moisture content of fresh hops, which can be 75% to 80%, has to be immediately reduced to under 12%, otherwise the hop would quickly become mouldy and spoil. Finally, the dried hops are packed and stocked in bales, preferably at low temperature.