The Homebrewer's Ultimate Guide To Hops

What Are Hops?

So, what are hops?

Hops plants, or Humulus lupulus, are used in brewing beer (duh!). Hops have natural preservatives, bitterness, aromas, and flavors, making them a primary ingredient in beer.

The female cone-shaped flowers of the plant are used, which contain lupulin glands that produce resins, oils, and other compounds that impart a bitter hop taste, flavors, and aromas to finished beer.

The appearance and properties of hop cones can vary across different hop varieties. The plant regrows from an underground rhizome annually and climbs using a twisting bine.

What do hops look like?

Hops are flowering plants that produce cone-shaped flowers. The cones comprise overlapping leaflike structures called bracts, which surround and protect the soft systems inside called bracteoles.

The bracteoles give the hop cone structure and shape and contain the yellow-gold powder-looking substance called lupulin glands. Lupulin glands impart the characteristic bitterness (alpha acids) and most of the hops' flavors and aromas (oils).

A hop plant grows on a climbing shoot called a bine, which twists itself in a helix around a support as it rises. The appearance of hop cones can vary in size, shape, and color across different hops. Overall, hops have a distinctive look with cone-shaped flowers and overlapping bracts.

What compounds are in hops?

Hops are selected for their sensory potential, bittering agents, hoppy aroma, and finishing flavors. Important quantitative metrics for hop quality include alpha acid, cohumulone, and total oil content. Alpha acids represent the bittering potential of hops, while beta acids play a crucial antimicrobial role. Cohumulone is a key alpha acid found in all hops that can present a harsher bitterness at high levels.

Total oil content represents the potential of a hop to provide flavor and aroma, and essential oils are highly concentrated compounds responsible for aroma. Different terpenes and thiols predominate in hop oils to create diverse hoppy flavors. Dried hop cones are typically comprised of cellulose, proteins and minerals, water, tannins and polyphenols, alpha acids, beta acids, essential oils, other acids, fats, and simple sugars.

Hop acids

Hop acids are the main contributor to bitterness in beer. Here is an overview of the different acids and the role they play.

Alpha acids

Alpha acids are compounds found in the soft resin of the lupulin gland in hops, which are responsible for the bittering potential of the hops. When isomerized during boiling, they create bitterness in the finished beer. The amount of alpha acids in a particular hop determines its potential for bitterness, and they can make up anywhere from 2 percent to over 20 percent of the total composition of a hop.

cohumulone

Cohumulone is an important alpha acid found in all hops. It is measured as a percentage of the total alpha acids. When present at high levels, it may present a harsher bitterness. Some brewers seek higher levels of cohumulone, while others prefer lower levels depending on their needs for a particular beer style.

Beta acids

Beta acids are a component of the soft resin in hops, which play an antimicrobial role but have limited solubility in water. They aid in retaining a hop's bittering potential as it ages.

Hop oils

There are many different oils that contribute to hop taste. Here are the major ones:

Caryophyllene

Also found in rosemary; contributes earthy, woody, and spicy flavors.

Humulene

Also found in cannabis; contributes herbal and dank flavors.

Myrcene

Also found in mangoes; contributes citrusy, fruity, and peppery flavors.

Farnesene

Also found in apple skins; contributes herbal, grassy, and citrusy flavors.

Linalool

Also found in lavender; contributes candy spice, floral, and orange flavors.

Limonene

Also found in lemons; contributes lemon, tangerine, and citrusy flavors.

Pinene

Also found in pine needles; contributes piney, and resinous flavors.

Thiols

Hop thiols are highly aromatic organic compounds in hop oils. They are among the many active sulfur-containing mercaptans known for their pungent odor. Hop thiols provide many complex tropical fruit flavors and aromas in hop oils. Therefore, hop thiols are crucial in determining the flavor and aroma profile of hops used in beer making. Thiolized yeast can help bring out these aromas and flavors.

How are hops used in beer?

Hops are one of the four essential ingredients in beer, and they are added to the boiling stage of brewing. The hops are isomerized at these temperatures, releasing alpha acids that impart bitterness. This bitterness increases the IBU of a beer and balances the sweetness of the malt. IBU, or “International Bittering Units,” measures the iso-alpha acids in a beer, indicating its bitterness.

Hops also contain oils that flavor and stabilize the finished beer. The choice and timing of hops can vary depending on the desired beer style. For instance, hops can be added later in the boil for more aroma or even dry-hopped or fresh-hopped for unique flavors. Hops can vary in taste and regional characteristics, and their role in a beer can range from starring to supporting.

First wort hopping

First wort hopping consists of adding hops to the boil kettle as it heats from mash temperature to boiling. The extra time creates a stronger hop aroma, a smoother bitterness, and a more complex hop flavor.

Not everyone agrees that first wort hopping, or FWH, makes a difference. Because it’s so easy to try, it’s worth experimenting to see if it works for you. We’ll run down the pros and cons in this guide and give tips on how to first wort hop your own beer.

Bittering hops

Bittering hops are added during the boiling process to release bitter-tasting Isohumulone. They are high in alpha acids, beer's primary source of bitterness. They are boiled for 15-90 minutes to isomerize the alpha acids. The bitterness in beer is measured in International Bitterness Units (IBU).

Some commonly used bittering hops include Chinook, Magnum, Galena, and Warrior hops, which have high alpha acid contents. Noble hop varieties can also be used for bittering, depending on the beer style. When using hops for bittering, the rule of thumb is that the more heat, the more bitterness you will achieve.

Aroma hops

Aroma hops add flavor and aroma to beer due to their high oil content. These hop oils and terpenes are also in fruits, spices, and other plants like cannabis, so they can add similar aromas and flavors.

These hops are typically low in alpha acids, usually with an alpha-acid percentage of less than 10%. They have a 1:1 ratio of alpha to beta acid contents, making adding significant bitterness to a beer with aroma hops harder.

Aroma hops should be used late in the boil or in a dry hop to extract the maximum flavor and aroma. The oils in aroma hops are considered volatile. They can evaporate pretty fast if left in the boil for too long. They are best extracted at a medium whirlpool temperature of 160–170°F (71–76°C) or when dry-hopping.

Hop stand

A hop stand is a brewing technique where hops are added after the boil and allowed to steep in the wort for an extended period. This is typically the whirlpool stage in a craft brewery, but homebrewers often don't have the necessary equipment to whirlpool or choose not to. The goal is to capture the delicate hop aroma without driving off the essential oils with prolonged contact in boiling wort.

Hop stands can be used to add a small amount of bitterness and lots of hop aroma to a variety of beer styles. The length of the stand can range from 10 to 90 minutes, depending on the desired results. At Bison Brew, we almost always do a 20-30 minute hop stand. The temperature of the wort during the hop stand affects the bitterness and essential oil extraction from the hops. We recommend a hop stand in the 140 - 170F (60 - 76C).

Dry hopping

Dry hopping is a brewing technique used to enhance the aroma and flavor of craft beer. It involves adding hops, either whole or in pellet form, to the beer fermenter after the primary fermentation is complete. It is much harder to dry hop with entire flower hops than with pellets, especially on the homebrew scale.

Dry hopping allows the volatile oils and compounds in the hops to infuse into the beer without being boiled off, resulting in a more complex aroma and flavor profile. The hops are typically left in contact with the beer for several days to a week, depending on the desired intensity of the hop character.

If you dry hop during primary fermentation, the hops can go through biotransformation, releasing bound thiols that increase flavor and aroma if the yeast you are using is capable of it.

Dry hopping is a common technique used in various beer styles, but it is ubiquitous in American-style IPAs and other hop-forward beers.

Hop products

Hops come in a variety of forms. Here are some of the more used hop products along with some new products that you should definitely try out in your hop forward beers.

Fresh hops

Fresh hops, sometimes called green or wet hops, are harvested directly from the bine and used in brewing within 24-48 hours without being dried. As hops are perennial plants, they can only be obtained fresh during the hop harvest season, typically between mid-August to late September in the northern hemisphere.

Whole leaf

Whole leaf hops, occasionally called raw hops, are the dried and pressed inflorescences of female hop plants that embody the characteristics of the variety, growing season, and farm management systems. They are available in most hop varieties and can be used in all stages of the brewing process, from kettle bittering through dry-hopping in the fermenter. They have improved trub formation, antimicrobial and anti-foaming properties in the kettle. They can be used for bitterness or aroma, depending on usage.

Pellets

Pellet hops have been ground up and compressed into pellet form. They are known for their high extraction efficiency when used for bittering in brewing beer, yielding about 10% more IBUs per ounce compared to whole hops of the same variety.

Pellet hops are also more stable and less prone to oxidation than whole hops due to their compressed form. They are commonly used in commercial brewing and are more readily available for homebrewing. While whole hops are preferred for dry hopping due to their easy removal and fresh aroma, pellet hops are still viable and provide a similar hop flavor profile.

Cryo Hops (Lupulin Powder)

Cryo hops are made from hop-processing technology that separates whole hop cones into two components: concentrated lupulin and their bract. This process uses low temperatures in a nitrogen-rich environment to preserve the hop components.

Cryo hop pellets are the concentrated lupulin of whole-leaf hops containing resins and aromatic oils. They are designed to provide intense hop flavor and aroma, allowing brewers to efficiently dose large quantities of alpha acids and oils without introducing astringent flavors or vegetative material.

Cryo hop pellets have nearly twice the resin content of traditional hop pellets and offer reduced grassy and vegetal characteristics. They also increase yield through reduced brewhouse and cellar trub and provide cost savings and net increases in revenue per batch.

Lupulin powder was the previous form of Cryo Hops. The same process was used to make them, they just came in a powder form instead of a pellet form which was generally harder to use.

Hop extract

Hop extract is a concentrated resin extracted from hops using supercritical CO2 extraction. It contains essential bittering and aromatic compounds, such as alpha acids, beta acids, and hop oils, contributing to beer bitterness, aroma, head retention, and stability.

Hop extract is a cleaner and more efficient way to bitter beer than pellets or whole-leaf hops. It eliminates much of the vegetal material and reduces trub. Hop extract can also provide variety-specific flavor and aroma contributions when used for late kettle or whirlpool additions. Additionally, hop extract has extended shelf life and reduced storage requirements compared to regular hops or pellets.

Hop terpenes

Hop terpenes are the essential oils found in hops that give the plant its characteristic aroma and flavor, essential for producing hop-forward beer. Hop terpenes can impart specific notes and scents to beer, such as grapefruit and pine for a West Coast IPA or mango and citrus for a New England IPA. When hops are boiled in wort to make beer, many terpenes are extracted, but they are volatile, so much of that essence can be lost.

Liquid hop terpenes are made by breaking up standard hop pellets and processing them through a supercritical CO2 extractor. Brewers can use them to impart more distinct flavors and aromas in their beer. Hop terpenes contain up to five major and thirty to forty minor notes in their aroma profile. Using liquid hop terpenes in brewing can also improve yield, one of the main advantages.

Hops Listed Alphabetically

All of the hops we have data on have been listed alphabetically. Click on a hop below to view its brewing information (alpha acids, oil content, etc.) as well as aroma profiles, substitutions, commonly paired hops, and recommended beer styles.

A

Adeena, Admiral, African Queen, Agnus, Ahtanum, Akoya, Aloha Blend, Altus, Amarillo, Apollo, Aquila, Aramis, Ariana, Astra, Aurora, Azacca

B

Banner, Belma, Bianca, Bitter Gold, Boadicea, Bobek, Bramling Cross, Bravo, Brewer's Gold, Brooklyn, BRU-1, Bullion

C

Callista, Calypso, Cascade Hops, Cashmere, Celeia, Centennial Hops, Challenger, Chelan, Chinook, Citiva, Citra, Cluster, Columbia, Columbus, Comet, Contessa, Crystal, CTZ

D

Delta, Denali, Dr. Rudi

E

East Kent Goldings, Eclipse, Ekuanot, El Dorado, Ella, Endeavour, Enigma, Equinox, Ernest, Eroica, Eureka, Evergreen Blend

F

Falconer's Flight, First Gold, Fuggle

G

Galaxy, Galena, Glacier, Godiva, Golding, Green Bullet

H

Hallertau, Hallertau Blanc, Hallertau Gold, Hallertau Mittelfrüh, Hallertau Taurus, Hallertau Tradition, HBC 472, HBC 586, HBC 630, HBC 638, HBC 682, HBC 692, Helga, Herkules, Hersbrucker, Horizon, Huell Melon

I

Idaho 7, Idaho Gem

J

Jarrylo, Julius

K

Kazbek, Kohatu

L

Lambic, Legacy, Lemondrop, Liberty, Loral, Lotus

M

Magnum (GR), Magnum (US), Mandarina Bavaria, Medusa, Meridian, Merkur, Millennium, Mosaic, Motueka, Mount Hood, Mount Rainier, Moutere, Multihead

N

Nectaron, Nelson Sauvin, Neo1, Newport, Nobility Blend, Northdown, Northern Brewer (GR), Northern Brewer (US), Nugget

O

Olicana, Olympic

P

Opal, Pacific Crest, Pacific Gem, Pacific Jade, Pacific Sunrise, Pacifica, Pahto, Palisade, Pekko, Perle (GR), Perle (US), Phoenix, Pilgrim, Pilot, Polaris, Premiant, Pride of Ringwood

R

Rakau, Riwaka

S

Saaz (CZ), Saaz (US), Sabro, Samba, Santiam, Saphir, Savinjski Golding, Sequoia Blend, Simcoe, Sitiva Blend, Sládek, Sorachi Ace, Southern Cross, Southern Passion, Southern Star, Sovereign, Spalter Select, Sterling, Sticklebract, Strata, Strisselspalt, Styrian Golding, Sultana (Denali), Summer, Summit, Sunbeam, Super Galena, Super Pride, Sussex, Sylva

T

Tahoma, Taiheke, Talus, Target, Tettnang (US), Tettnanger, TNT Blend, Tomahawk, Topaz, Trident, TriplePearl, Triskel, Triumph, Tropica

U

Ultra

V

Vanguard, Vic Secret, Vienna Gold, Vista

W

Wai-iti, Waimea, Wakatu, Warrior, Willamette

Y

Yakima Gold

Z

Zamba Blend, Zappa, Zenith, Zeus, Zythos