Tag: hop

Hops are the cone-shaped flowers of the hop plant humulus lupulus, and they are responsible for the bitter taste and much of the aroma in a beer. The first documented cultivation of hops occurred in 730s AD in the Hallertau region of Germany, but by most accounts they were not widely used in beer brewing until approximately 350 years later. Today there are well over 80 unique varieties of hops that are commonly used to brew beer.

The soft resins and oils used to bitter beer and impart aroma are contained in the lupilin glands of the female hop flower. The hops’ resin is comprised of alpha and beta acids. The alpha acid in hops is the primary source of bitterness and also acts as a preservative in beer. When heated in the brewing process, alpha acids are isomerized and form iso-alpha acids. The amount of time that the alpha acid is subjected to the boil determines the degree of isomerization that occurs, and the amount of bitter flavoring that is produced in the beer.

At a certain point, the boiling begins to have significantly diminished returns on the isomerization of the alpha acid and it becomes ineffective for creating additional bitterness in the beer. Typically that occurs 60 to 90 minutes after adding the hop to the heated wort. The isomerization process occurs when the wort is heated above approximately 175° F. The quantity of alpha acid present in a hop will determine the hop’s bittering potential.

Alpha acid percentages vary dramatically between the different varieties of hops and are impacted by a multitude of outside factors such as storage packaging, age of the hop, storage temperature, oxidization, drying method, and growing conditions. Unlike alpha acid, beta acid imparts only a small portion of the total bitterness in a beer. Yet beta acids are important because, as the alpha acids’ bitterness breaks down over time during fermentation and storage, beta acids create a sharper bitterness as oxidation occurs. Unlike alpha acid, beta acid does not isomerize during the boil and is primarily responsible for the hop aroma in a beer.

Below is a list of commonly expected alpha and beta acid levels for different hop varieties. These are not exact and are just intended for estimation purposes:

Ahtanum Hop, Alpha Acid 5.5-9%, Beta Acid 5-6.5%

Amarillo Hop, Alpha Acid 6-11%, Beta Acid 6-7%

Apollo Hop, Alpha Acid 15-21%, Beta Acid 5-8%

Australian Galaxy Hop, Alpha Acid 12-14%, Beta Acid 5.5%-6.5%

Australian Helga Hop, Alpha Acid 5-6.5%, Beta Acid 4-5%

Australian Pride of Ringwood Hop, Alpha Acid 6-8.5%, Beta Acid 4.5-5.5%

Australian Stella Hop, Alpha 14-16%, Beta Acid 4.5-5.5%

Australian Super Pride Hop, Alpha Acid 13-15%, Beta Acid 6-7%

Australian Sylva Hop, Alpha Acid 4.5-7%, Beta Acid 3-5%

Australian Topaz Hop, Alpha Acid 15-18%, Beta Acid 4-5%

Bravo Hop, Alpha Acid 14-17%, Beta Acid 3-4%

Calypso Hop, Alpha Acid 12-14%, Beta Acid 5-6%

Cascade Hop, Alpha Acid 4.5%-7%, Beta Acid 4.5-7%

Centennial Hop, Alpha Acid: 9.0-12.0%, Beta Acid 3.5%-4.5%

Chinook Hop, Alpha Acid 11-13%, Beta Acid 3%-4%

Citra Hop, Alpha Acid 11-13%, Beta Acid 3.5-4.5%

Cluster Hop, Alpha Acid 5.5-9%, Beta Acid 4.5%-6%

Columbus Hop, Alpha Acid 14-16%, Beta Acid 4.5%-5.5%

Crystal Hop, Alpha Acid 2-4.5%, Beta Acid 4.5%-6.5%

Czech Saaz Hop, Alpha Acid 3-4.5%, Beta Acid 3-4%

Delta Hop, Alpha Acid 5.5-7%, Beta Acid 5.5-7%

El Dorado Hop, Alpha Acid 13.5-16%, Beta Acid 7-8%

Falconer’s Flight Hop, Alpha Acid: 10-11%, Beta Acid 4.5-5.5%

French Strisselspalt Hop, Alpha Acid 3-5.5%, Beta Acid 3-6%

Galena Hop, Alpha Acid Pellets 12-14%, Beta Acid 7-9%

German Brewer’s Gold Hop, Alpha Acid 5-9%, Beta Acid 2.5-3.5%

German Hallertau Hop, Alpha Acid 3-5%, Beta Acid 4-5.5%

German Herkules Hop, Alpha Acid 12-17%, Beta Acid 4.5-5.5%

German Hersbrucker Hop, Alpha Acid 1.5-3.5%, Beta Acid 4.5-6%

German Magnum Hop, Alpha Acid 13-15%, Beta Acid 5-7%

German Merkur Hop, Alpha Acid 12-15%, Beta Acid 5-7.5%

German Northern Brewer Hop, Alpha Acid 8-10%, Beta Acid 5-6.5%

German Opal Hop, Alpha Acid 5-8%, Beta Acid 3-5.5%

German Perle Hop, Alpha Acid 6.5-9%, Beta Acid 5-6.5%

German Saphir Hop, Alpha Acid 2-4.5%, Beta Acid 2-4.5%

German Select Hop, Alpha Acid 3-6.5%, Beta Acid 3-4.5%

German Smaragd Hop, Alpha Acid 4-6%, Beta Acid 4-5%

German Spalt Hop, Alpha Acid 4-5.5%, Beta Acid 4-5%

German Tettnang Hop, Alpha Acid 3.5-5.5%, Beta Acid 5-6%

German Tradition Hop, Alpha Acid 5-7%, Beta Acid 4-5%

Glacier Hop, Alpha Acid 5.5%-6%, Beta Acid 6-8%

Horizon Hop, Alpha Acid 11-13%, Beta Acid 6.5-8.5%

Liberty Hop, Alpha Acid 3-5%, Beta Acid 3-4%

Millennium Hop, Alpha Acid 13.5-16%, Beta Acid 4.5-5.5%

Mosaic Hop, Alpha Acid: 11.5-13.5%, Beta Acid 3-4%

Mt. Hood Hop. Alpha Acid 4-7%, Beta Acid 5-7.5%

Mt. Rainier Hop, Alpha Acid 6-8%, Beta Acid 5-7.5%

Newport Hop, Alpha Acid 12-14%; Beta Acid 7-9.5%

New Zealand Green Bullet Hop, Alpha Acid 11-14%, Beta Acid 3-6%

New Zealand Hallertau Hop, Alpha Acid 6.5-8.5%, Beta Acid 3-4%

New Zealand Motueka Hop, Alpha Acid 6.5-7.5%, Beta Acid 5-6%

New Zealand Pacific Gem Hop, Alpha Acid 13-15%, Beta Acid 7-9%

New Zealand Pacific Hallertau Hop, Alpha Acid 5-6%, Beta Acid 3-4%

Nugget Hop, Alpha Acid 9-11%, Beta Acid 4-6%

Palisade Hop, Alpha Acid 5.5-9%, Beta Acid 6-8%

Perle Hop, Alpha Acid 7-9.5%, Beta Acid 4-5%

Santiam Hop, Alpha Acid 5.5-7%, Beta Acid 6-8.5%

Simcoe Hop, Alpha Acid 12-14%, Beta Acid 4-5%

Sterling Hop, Alpha Acid 6-9%, Beta Acid 4-6%

Styrian Aurora Hop, Alpha Acid 7-9%, Beta Acid 3-4.5%

Styrian Bobek Hop, Alpha Acid 3.5-7%, Beta Acid 4-6%

Styrian Celeja Hop, Alpha Acid 3-6%, Beta Acid 2-3.5%

Styrian Goldings Hop, Alpha Acid 4.5-6%, Beta Acid 2-3%

Summit Hop, Alpha Acid 17-19%, Beta Acid 4-5%

UK Admiral Hop, Alpha Acid 13-16%, Beta Acid 4.5-6.5%

UK Bramling Cross Hop, Alpha Acid 5-7%, Beta Acid 2-3.5%

UK First Gold Hop, Alpha Acid 6-9%, Beta Acid 3-4.5%

UK Fuggle Hop, Alpha Acid 3-5%, Beta Acid 5-6.5%

UK Kent Goldings Hop, Alpha Acid 4-5.5%, Beta Acid 2-4%

UK Minton Hop, Alpha Acid 5-7.5%, Beta Acid 3.5-4.5%

UK Northdown Hop, Alpha Acid 7.5-9.5%, Beta Acid 5-6%

UK Phoenix Hop, Alpha Acid 8-12%, Beta Acid 4-6%

UK Pilgrim Hop, Alpha Acid 9-13%, Beta Acid 4.5-6%

UK Progress Hop, Alpha Acid 5-7%, Beta Acid 2-3%

UK Target Hop, Alpha Acid 8-13%, Beta Acid 4.5-6%

UK Whitbread Goldings Hop, Alpha Acid 5-8%, Beta Acid 2-4%

US Brewer’s Gold Hop, Alpha Acid 8.5-9.5%, Beta Acid 3-5%

US Fuggle Hop, Alpha Acid 4.5-5%, Beta Acid 1-2%

US Goldings Hop, Alpha Acid 4-6%, Beta Acid 2-3%

US Northern Brewer Hop, Alpha Acid 8-10%, Beta Acid 3-5%

US Saaz Hop, Alpha Acid 3-4.5%, Beta Acid 3-6%

US Tettnang Hop, Alpha Acid 3.5-6%, Beta Acid 3-4%

Vanguard Hop, Alpha Acid 5-7%, Beta Acid 5-7%

Warrior Hop, Alpha Acid 14-16%, Beta Acid 4-5.5%

Willamette Hop, Alpha Acid 4-6%, Beta Acid 3-4%

Zythos Hop, Alpha Acid 10-11%, Beta Acid 5-6%

A photo of a cascade hop plant just prior to harvesting.

Cascade hops ready to be used.