What are Hops in Beer?

Ever wonder what those little green, cone-shaped flowering plants that look like small pine cones are? Hops. They give beer the “hoppy” aroma, flavor and bitter taste to balance out the malts, sugars and grains.


In today’s blog post, Lost Signal Brewing in Springfield, Missouri explains everything you need to know about the hop plant. Read on.


What are Hops & How are They Used?

Humulus Lupulus, otherwise known as a female hop plant, is a non-woody, annual perennial plant, or climbing flower, that belongs to the hemp family (Cannabaceae) — a cousin to cannabis.


Hops are what keep beer fresh and give it that foamy, white top. Hops basically determine the bitterness, flavor, and aroma of a beer. Bitterness doesn’t just come from hops. It can come from fruit, veggies, spices, or herbs added to the brew.


Hops aren’t just used in beer either. Teas and sodas can have hops too. They can even be eaten. That’s right. The young shoots of the vine are technically edible and can be cooked like asparagus. Hops are also used in herbal medicines as a sedative.


A Really Brief History of Hops

Hops likely originated in China. Hops were first used for brewing in the 8th century by Benedictine monks. Before hops started getting used in the Middle Ages, brewers used gruit instead, a combination of mugwort, and various herbs and spices.


Facts on Humulus Lupulus

infographic describing hop plant facts


Two Categories of Hops

Bittering Hops

AKA kettle hops. They’re added at the start of the boil for around an hour. Cheap hops are used here since all the flavor gets boiled away. High alpha acids are better for bittering.


Aromatic Hops

Known as finishing hops, these are added near the end of the brewing process to give a particular flavor profile and smell. Low alpha acids are better for adding aromatic flavor.


Dual Hops.

A combination of the two.


How are Hops Processed?

Hops are picked from the farm, put on a truck and transported to a processing facility. The hops are separated from the leaves on a dribble belt.


Once separated, they’re transferred to a kiln to go through several stages of processing.


Hops are dried to remove moisture and are then put into a bailing room to get conditioned at room temperature for one day.


Finally, the hops are rolled off of a conveyor belt and packaged into packets to be shipped to brewing companies.


Hops Come in a Few Forms

Processed hops come in four forms. The most common are…

Whole hops, otherwise known as “raw hops” or “leaf hops” (the whole dried coneflowers of the hop plant) or pellet hops (where the hop is ground up and pressed into pellets).


Hop plugs are another form, very similar to pellets, but in the shape of a small hockey puck.


Hop extract is a liquid form of hops. It is a more volatile and perishable form, however. It’s common to throw in cheaper, common whole hops into a boil for “dry-hopping.” This is because all of the acids get boiled away.


The more expensive hops are used after a boil for their bittering or aromatic properties.


Hops: Alpha Acids

Hops have little buds called lupulin glands that carry alpha acids, (found within soft oil resins). These acids are a compound that determines the bitterness of the hops. Acid levels are the most potent right after harvest but diminish due to oxidation.


The hops used in the brewing industry are the dried female flower clusters (cones) of the common hop (H. lupulus) plant.


Hops Have 4 Categories

Hop categories are based on alpha acidity levels.

  1. Low-Alpha Aroma - 2.5-6%

  2. Dual-Purpose - 6-10%

  3. High-Alpha - 10-15%

  4. Super-Alpha - 14-18%


A few cutting-edge brewers out there have created unique flavor characteristics (super ultra mega alpha acids — we’re joking here).


Chemical Compounds of Hops: AAU, HBUs, IBUs

AAUs are alpha acids, the chemical compound found in hops, and are a measurement of the bitterness in hops.


HBU - Homebrew Bitterness Unit (another measurement that home brewers have)


IBU - International Bitterness Units. One Bitterness Unit is equal to 1 milligram of isomerized alpha acid in 1 liter of wort or beer or 1 part per million isomerized alpha acid. Beers with high IBU have higher “iso-alpha acids” (isomerized alpha acids).



The Sex of Hops

There are males and female hops. Female Hops are used in beers and teas. Male hops are rarely ever used. If they’re spotted, farmers will often prune them in order to keep them from pollinating the female hops.


If the female hops are pollinated, little white-colored seeds appear within them. Hops with or without seeds don’t make much of a difference to the flavor. It’s more common in Britain to see hops with seeds in them. In America, we prefer seedless hops.


Hop Families and Hop Genus

Just like flowers and other plants, hop families are paired and bred to create new, distinct varieties of hops. Over the last several years, this has happened a lot.


This is why there are so many unique varieties of craft beer available today, the distinct aroma and bitterness, or lack thereof, are attributed to the hops used in the brewing process.


Male hops in the wild are rare. Female hops are common. Hop breeders use the USDA pedigree male hops to breed new female hops. Wild, feral male hops are rare. If they’re found, they’re eliminated immediately, before pollinating the females.


3 Dominant Styles of Hops

These hops are categorized based on their geographical location.


American Hops. Ranging in flavor, but often “citrusy.”

British Hops. Hops originating from the British Isles.

Noble Hops. High-quality German & Czech hops.


How Many Types of Hops are There?

There are approximately 80 types of hops. As of today, that number is probably far bigger. New hops are still being created and dubbed in all kinds of marketable terms.


“Noble hops,” for instance, is more of a marketing term for hops that have low bitterness and high aroma.


Get Amazing Craft Beer Brews at Lost Signal Brewing

At Lost Signal Brewing, we don’t just cook up amazing barbecue, we create delicious seasonal craft beer brews. Stop by our brewery on 610 W. College Street, right off the square in downtown Springfield. Contact us for more information or call us at 417-869-4755.


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