Hop Hash: What It Is & How to Use It
In the quest for the perfect IPA, brewers recently stumbled upon hop hash, the purest and most potent natural form of hops cur
rently available. It is a concentration of lupulin glands (which is where all of the hop oils and resins are formed) and other hop dust that is left behind after the pelletizing process. Hop hash ranges in form from a fine powder to sticky nuggets that depends on the oil content of the hop cone. The kind of hash depends on the variety of hop being pelletized, but not every variety will produce hash.
For decades this material was discarded, along with other unusable parts of the hop, because it gummed up all of the pelletizing machines. It was the responsibility of the lowest grunt in the pellet mill to scrape down the machinery because the hop hash was so sticky, resinous, and hard to clean. When brewers and hop professionals started to brew with the hop hash they were laughed at by the manufacturers, but soon producers realized brewers wanted the hop hash so badly that they were willing to come in and scrape down the machines themselves to get it.
Cellulose and lignin combine to make up about 50 percent of a hop cone’s total weight. Protein and water account for up to another 30 percent. That means that, at maximum, only 30 percent of the hop cone is the good stuff like alpha and beta acids and oils or resins. The delicate hop oils that contribute the zesty and pungent aromas and flavors sought after in today’s IPAs comprise only three percent of a hop cone by weight. But in hop hash, the oil content can reach almost five milliliters per 100 grams. Since hop hash is mostly made up of these oil-producing lupulin glands, it has the highest natural concentration of oils of any hop product. The alpha and beta acids are also in such high concentration (around 30 percent by weight for alpha acids) that the same bitterness, flavor, and aroma can be achieved with half as much hash as pellets.
Even though hops have been thoroughly scientifically studied in America since the 50s, there are still hundreds of unnamed oil compounds. In 1992 there were 250 aroma compounds identified above aroma threshold concentration in a hop cone and since then that number has only grown. These oils can lend flavors and aromas of peaches, strawberries, or any fruit imaginable. Now the science is recognizing that these oils have a very complex relationship with each other. Not only does it matter what oils are present and how much of each, but the combination of certain oils can also produce lots of unique flavors and aromas. These oils combine and interact with each other to form almost a limitless number of combinations for new aromas and flavors.
How to Use Hop Hash
Professional brewers have experimented with hop hash for a couple years now, but it is just becoming available for the first time to homebrewers. Since it is available only during certain times of the year (post hop harvest) and in such small amounts, it is important to make the most of it. Hop hash can only be harvested when the pellet mills are running, which is usually from October through February in the US, and is by nature very limited and rare. It can take thousands of pounds of hops being pelletized to yield a couple pounds of hash.
Hop hash can be used for any hop addition, but using it for cold side additions will help to preserve the lighter volatile oils that normally burn off during boil. Whirlpooling with hop hash, as the wort cools from 190 °F (88 °C) down to 160 °F (71 °C), is a great way to extract those juicy and zesty aromas. Anecdotally, brewers say that even just a couple degrees difference means pulling out a whole new set of oils while burning off others. So experiment with adding hop hash at different temperature ranges. The duration of the whirlpool will also matter because there is mechanical as well as chemical extraction of oils. Dry hopping with the hop hash has also yielded interesting results. The new trend is to dry hop during primary fermentation to try and promote interaction between the hops and the yeast in what is being called biotransformation. Traditionally, hops should be left in dry hopping for no longer than 72 hours. This is to prevent the beer from smelling overly grassy or vegetal due to the decomposing cellulose in the hop cone. But since hop hash is separated from the cellulose and other plant matter, the risk of getting off-flavors from dry hopping too long is low.
Hop hash is best used fresh. The fine powder has more surface area, which can be exposed to more oxygen. This oxidation will lower the alpha acid percentage over time, but any assessment of how hop hash changes as it ages is anecdotal and not empirical. Store hop hash in a place that is dark and cold.
