This post was written by Nicole Emanuel, a recent graduate of Macalester College and a former ABG employee and current volunteer!
Beer and botany—what could be a better pairing? Leading up to our July 13 Beer in the Garden event, we’ll be sharing some information about the biology of plants used by brewers!
First up is the most famous of all plants associated with beer: Humulus lupulus, also known as the common hop plant. It is a climbing plant similar to a vine, which often grows to about 25 feet in height. The female flowers of H. lupulus are the part of the plant that are actually known as “hops,” and that are harvested for use in beverage production. Male and female flowers are wind pollinated and typically grow on separate plants in this species. The hop plant is a perennial that sends up new growth each spring. It is native to North America, Europe, and Asia.
Hops act as flavoring and preservative agents. As most beer enthusiasts know, hops contribute bitterness to the taste and aroma of beer. Over the years, humans have bred different varieties of hops to cultivate desired traits. Some plants are bred to have especially abundant flowers, or to thrive with shorter hours of daylight. Other cultivars are prized for their flavor profiles, which can give a brew notes of “citrusy,” “grassy,” or “earthy” taste. In addition to the crucial role hops play in shaping the savor and smell of beers, they also help to preserve the beverage by killing microorganisms that could cause it to spoil. Brewers have been exploiting hops’ anti-microbial properties for hundreds of years. In fact, prior to the 9th Century, people made beer with a wide range of herbs and flowers (including dandelion and marigold). It is thought that once the preservative effects of hops were noted, the plant gained popularity and replaced other ingredients.
And it’s not just humans who benefit from the power of hops: scientists from the USDA and the Carl Hayden Bee Research Center recently concluded that H. lupulus might be useful in preventing colony collapse in honey bees! They found that hop beta acids fight pests such as varroa mites, which can attack the health of bee populations. Hives treated with acids isolated from hops were protected from mites, without showing any harm to their bee residents. (http://environment-review.yale.edu/beer-hops-beneficial-honey-bees-0)
Beloved by humans and bees alike, Humulus lupulus is a truly wonderful plant. Check out the specimen growing in our lower perennial garden!