Identifying Hops In Beer: A Guide To Flavor And Aroma

Hops are the flowers (also called seed cones or strobiles) of the hop plant Humulus lupulus. They are used as a bittering, flavouring, and stabilising agent in beer, adding bitterness, aroma, and flavour. Hops are also used in other beverages, herbal medicine, and food products. The different types of hops used for particular styles of beer include Columbus, Centennial, Citra, Simcoe, Tettnanger, Mosaic, Cascade, and Centennial.

Hops are the flowers of the female hop plant, Humulus lupulus

Hops are the flowers (also called seed cones or strobiles) of the female hop plant, Humulus lupulus. They are used to balance the sweetness of the malt in beer with bitterness and a variety of flavours and aromas. Humulus lupulus is a member of the Cannabaceae family of flowering plants, which also includes Cannabis (hemp and marijuana). Hops are hardy plants and are grown all over the world.

The hop plant is a vigorous, climbing, herbaceous perennial. When grown commercially, it is usually trained to grow up strings in a field called a hopfield, hop garden, or hop yard. The separate male and female hop plants develop their flowers on different plants, and only the female plants are used for commercial production. The female plants are propagated vegetatively, and the male plants are culled if plants are grown from seeds.

Hops are packed with alpha acids, which are the primary bittering agent used in brewing to balance the sweetness of the beer. They also contain essential oils that lend many beers their signature, intoxicating flavours and aromas. Hops are added at different stages of the brewing process, depending on the desired effect. If added early in the process, the essential oils will volatilize (boil away), either during the boil or during fermentation. When added later in the process, the beer will smell "hoppier".

Hops also have a preservative effect on beer. Before modern refrigeration, hops served as an important preservative, and beers made with hops were less prone to spoilage.

They add bitterness, flavour, and stability to beer

Hops are the flowers, or cones, of the female hop plant, scientifically known as Humulus lupulus. They are used to add bitterness, flavour, and stability to beer.

Hops contain alpha and beta acids, which are the primary bittering agents used to balance the sweetness of the beer. The alpha acids are degraded during the brewing process to form iso-alpha acids, which are more soluble and contribute to the bitter flavour associated with beer. The beta acids have a harsher bitterness and, as they are insoluble, their contribution to the overall flavour is much lower. However, they oxidise slowly, so their bitter flavour becomes more potent the longer the beer is fermented and aged.

Hops also contain essential oils that lend beers their signature, intoxicating flavours and aromas. These oils are very volatile, evaporating easily, so hops are often added later in the brewing process or through a technique called "dry hopping", where the hops are soaked in the finished beer for several days or weeks.

The type of hops used and the length of time they are boiled for will affect the flavour and bitterness of the beer. Bittering hops are added at the beginning of the boil and are left for up to an hour and a half. This long boil destroys the essential oils in the hops, so if a brewer wants to preserve these delicate compounds, they will be added later in the process and boiled for a shorter duration. Aroma hops are added at the very end and boiled for a maximum of five minutes. Sometimes, they are not boiled at all and are instead steeped off the heat after fermentation.

Hops are categorised as either bittering or aroma hops

Aroma hops, on the other hand, tend to have a lower concentration of alpha acids and are the primary contributors of hop aroma and flavour. They are typically added to the wort later in the process to prevent the evaporation of the essential oils, which are responsible for the hoppy aroma. Aroma hops are often added after the wort has cooled and while the beer ferments, in a technique known as dry hopping, which further enhances the hoppy flavour.

Dual-purpose hops have high amounts of both alpha acids and essential oils, and can be added at any stage of the brewing process.

There are hundreds of hop varieties, with different flavours and aromas

Hops are the flowers (also called seed cones or strobiles) of the hop plant Humulus lupulus, a member of the Cannabaceae family of flowering plants. They are used primarily as a bittering, flavouring, and stability agent in beer.

Noble hops, which include strains like Saaz, Tettnanger, Spalt, and Hallertau, are considered the most classic. They are what lend traditional German and Czech pilsners and lagers their characteristic flavour profiles. Noble hops tend to be particularly rich in the high-aroma essential oil humulene and have low alpha-acid levels.

American hops, including strains like Cascade, Centennial, and Columbus, tend to be bold, bright, and highly aromatic. They generally have higher amounts of the essential oil myrcene, which gives them their characteristic citrus and pine notes.

English hops (e.g. Fuggle) have lower levels of myrcene, allowing the more subtle aromas of other essential oils to shine through. English hops' profiles tend to be more delicate and mild, with notes of earth, molasses, herbs, spice, and wood.

Within these broad categories, there are many hop strains to choose from, each with its own unique flavour and aroma characteristics. For example, the U.K. Northdown hop is known for its bittering potential and its fruity, tea, and citrusy aroma, while the U.K. Golding hop has delicate, sweet floral, and spicy aromas.

The wide range of flavours and aromas found in different hop varieties allows brewers to create beers with distinct characteristics, from the omnipresent IPA, where hops take centre stage, to stouts, where hops play a more subtle role.

Hops are added at different stages of the brewing process

Bittering hops are added at the beginning of the boil and are left to bubble and steep for at least 45 minutes and up to an hour and a half. The longer bittering hops are boiled, the more iso-alpha acids are produced, which gives the beer its bitter taste.

Flavouring hops are added with about 15 to 30 minutes remaining in the boil. During this time, very little bitterness is extracted from the hops, but the crisp hoppy flavour is imparted.

Aroma hops are added during the last 5 minutes of the boil or at flame-out, when the kettle is removed from the heat. This is because the hop oils responsible for the aroma are extremely volatile and will be driven off in the steam if boiled for too long. Adding aroma hops at flame-out will produce the maximum amount of aroma.

Frequently asked questions