What are the hops used in beer brewing?

Hops are crucial for a good beer. When discussing beer, you might often hear about hops, but do you know what they are?

What is the purpose of adding hops to the beer brewing process? What are their uses and functions?

Hops

Producing Regions

Hops are native to temperate regions. Due to climate constraints, hop-producing regions around the world are mostly located between 35 and 55 degrees latitude. Hops are grown in both the northern and southern hemispheres. Traditional hop-producing regions in Europe, such as Germany, the Czech Republic, and the United Kingdom, are the most well-known Old World regions.

In recent decades, North America, benefiting from the booming craft brewery industry, has become a major hop-producing region, primarily focusing on new hop varieties. Xinjiang, China’s main hop-producing region, is Xinjiang, while New Zealand in the Southern Hemisphere has become a popular hop-producing region in recent years.

Hop Growth

Hops are not actually the flowers of the plant, but rather its cones. Fresh hops are green in appearance, resembling a much lighter pine cone. However, they have a fluffy texture and can be easily formed into a small ball.

Hops regenerate annually, growing vines from underground rhizomes that climb upward. Hop plants typically grow up to 20 feet tall. Inside the cones are yellow, speckled lupulin, which is the source of hops’ aroma, alpha and beta acids, and essential oils.

Hops Have Two Important Functions

For brewers, hops have two important functions. The first is to provide bitterness. Bitterness comes from the isomerization of alpha acid during boiling. Beta acid, a similar component, contributes much less to beer flavor than alpha acid. Beta acids primarily have a significant impact on flavor when aged hops are used in traditional sour beers.

The second function of beta acids is the diverse and diverse essential oils in hops. These oils are the primary source of hop aroma, contributing to the beloved hop flavor. The composition and quantity of these essential oils vary depending on factors such as the variety, growing region, and climate.

Thus, even the same hop variety grown in different regions often produces significantly different flavors.

Hop Storage

The two functional components described above are easily affected by storage temperature, light exposure, and storage time, so hops are primarily stored frozen. Hops can be preserved even longer if packaged in opaque packaging and vacuum-sealed.

Do not store hops at room temperature or in the refrigerator alone, as the flavor will quickly fade and develop a heady, cheese-like or smelly sock-like odor.

Hops can improve beer’s shelf life.

Hop resins in hops inhibit bacterial growth (particularly lactic acid bacteria), so using hops can improve beer’s shelf life. Polyphenols in hops bind to some proteins in the malt, some of which separate during boiling to form hot breaks.

Other proteins condense during the rapid cooling of the wort after boiling, forming cold breaks. These condensed substances are then removed during lautering, indirectly contributing to the clarity of the final beer.

In addition, hops with high alpha-acid content tend to contain more isohumulones, which helps maintain the beer’s head.

Hop cultivation

Hops are dioecious, meaning the plant has male and female plants, and the hop cones brewers desire only appear on female plants. The function of male plants is pollination, helping to produce the next generation of seeds. Therefore, male plants offer no direct benefit to brewing.

In hop cultivation, hops are commonly grown asexually using the rhizomes beneath the female plants. Hop plants are not considered robust and are significantly affected by the environment and disease. A recent climate change disrupted the global hop supply.

During hop harvesting season, harvesting machines cut the hop vines at the base. The entire bunch is pulled into a harvester, and the hop cones are separated at the factory. The remaining plants are discarded. After separation, the cones are dried with hot air to facilitate future storage.

Hop Package

Depending on the intended use, some hops are packaged directly as dried cones. This is called leaf hops. Most hops are crushed and compressed into small pellets of varying sizes, becoming the commonly seen hop pellets.

The oils in hop pellets are less exposed to air, making them less susceptible to oxidation and preserving their flavor better. Furthermore, their smaller size makes them easier to freeze, so pellets are the majority of hops available on the market.

The Most Important Hop Parameter

◎ Alpha acid, commonly abbreviated as AA, is the most important hop parameter. Even within the same hop variety, alpha acid levels can vary slightly depending on the year and growing region.

When purchasing hops, you’ll often see a numeric percentage (%) following the confusing name. This indicates the alpha acid content of that batch. Hops with a higher alpha acid content produce a more bittering flavor when boiled for the same amount of time.