Hop Forms - All Comercial Ways to Buy it

Continuing the last article about Hops (link above), we will talk about hop forms, components extraction, and degradation of hopping. Both articles prepare a brewer or enthusiastic for our next step, hopping techniques. ?If you like this content, please subscribe for more!

Nowadays brewers can choose between several forms of hops. Each one provides specific characteristics that made it suitable or not for each hopping technique.

Whole hops: This is the less processed form of hop. The hop cone is harvested, air-dried, packed, and keep it cool stored. As whole hops are minimally processed, they keep many volatile aromatic compounds, making them a good choice for dry hopping. Some brewers believe that in this form, hops provide less harsh tastes than in pellet form, but this lacks scientific confirmation. It is possible to use hop flower staining the boiled wort to retain the hot break in a process called “hopbacking” (and providing aromas that would be volatilized if used in boiling)

Whole forms use more space to be stored, make the logistics more expensive, the contact area with wort is smaller (worsening the isomerization, reaching less than 10%), and they also have a shelf life shorter than pellets.

Pellets: To manufacture pellets, the hops are milled by a hammer miller (refrigerated if possible), and the powder is mixed and then pelletized. A great part of the lupulin glands is ruptured during this process, making the brewing utilization rate 10 to 15 % higher than that of whole hops. More than 60% of hops harvested are used to produce pellets.

Pellets can be lightly processed as hop plugs (Type 100 pellets) or enriched with lupulin. The most used pellet is T90s (Type 90 pellets), which has 90% of the nonresinous components found in cones. T45 is a lupulin-enriched pellet, it has twice more lupulin than T90 with less fibrous matter. T45 is processed in temperatures below -25°C.

It is possible to use a pre-isomerized pellet. By action of food-grade magnesium hydroxide under heat is possible to acquire isopellets that required only 15 minutes in contact with the wort.

Hop extract: The idea here is to pass a solvent (normally liquid CO2) through a column of pellets to collect components and remove solvent to produce an almost pure resin extract including none of the hard resins (tannins), no plant pigments, and less water.

The supercritical process is used to separate extract and solvend and is used in 95% of hop extraction. It yields a little more alpha acids (35 to 50%) and oil content (3 to 12%).

The cost per “IBU” may appear higher using hop extracts compare to pellets or whole hops but it reduces cost with logistics and storage, less beer (and wort) losses, and better utilization.

It is possible to refine the extract producing advanced hop products as described below:

Rho hop extract: It contains only dihydro-iso-alpha-acids (rho), beta acids, and hop oils. It can be used to prevent light-struck flavor (3-methyl-2-butene-1-thiol, or just MBT) caused by ultraviolet light. Rho has bitterness potential reduced, reaching 70% of the potential of traditional hops.

Beta-acids with hop oils: used to prevent foaming in the kettle and increase hop oils in wort.

Iso extracts: A solution of iso-alpha acids (concentration of 30%) used in beer to adjust bitterness.

Tetra extracts: tetrahydro-iso-alpha-acid is sold in 10% concentration and is used to enhance foam and avoid light-struck. The perception of bitterness is 1 to 1.7 times bigger than that of iso-alpha-acids.

Hexa extracts: hexahydro-iso-alpha-acids also provide an enhanced foam however the bitterness perception is similar to iso-alpha-acids.

Hop aroma products: there are a large variety of oils to enhance one or more characteristics of hop.

Degradations of Hops

To produce a higher quality beer is essential to use good and fresh raw materials. An aged hop can cause some off-flavors like “cheesy”, “grassy” and “catty” (tomcat urine odor) caused by alpha-acid oxidation.

To identify an old hop, a good indicator is a color. As hops age, it turns yellow and brown. The smell is also a strong indication, take care of "cheesy" and "musty" smells. It is possible to create a “hop tee” to volatilize the smells and make them easy to identify. Another technique is warm the pellet and rubs it with hand to smell it.

Hops take different times to get old, depending on the quality of storage, temperature, oxygen exposition and light, and variety of hops. To measure how old the hop is, there is an index called “hop storage index” (HSI) that uses spectrophotometric analysis to determine the ultraviolet absorbance (fresh hops absorb light at 325nm and oxidated compounds around 275nm).

The beer exposition to light can oxidate iso-humulone creating a very unpleasure smell known as “light-struck” or “skunk flavor”. That happens when beer is exposed to light in a range of 350 to 500nm, riboflavin (B2 vitamin) present in beer absorbs energy and transfers to iso-humulone, and the reaction goes on producing as a result in MTB, which is one of the strongest odorous substances known.

Dark beers absorb all visible light spectrum and pale beers only the blue light (its complementary color). To prevent the hop degradation in beer is recommended to store beer in metallic kegs, cans, and amber color bottles. Amber color bottles retain light at 500nm, while the green bottles are around 400nm, allowing happening the reaction described above.

How about you, comment which way you prefer to buy your hops for brewing. If you enjoy this content, please like and share it!