Tuesday, November 21, 2017

hop preservation methods: cryo magic

It’s hard to visit a brewery lately without some mention of hop science. Dry-hopping is now ubiquitous in many taprooms, and there has been increased discussion about how whirlpool additions of hops contribute to bitterness in addition to flavor. Recently, terms like hop powder, hop extract, and hop dust are populating beer menus, which leads me to ask, what exactly are these things?

Credit: Buffalo Beer Biochemist

Credit: Buffalo Beer Biochemist

I’ll admit that I am fond of the unrealistic but romantic notion that less processed ingredients are always better, whether in my food, coffee, or cocktail. I daydream about whole hop cones being tossed into batches at places like Victory Brewing Company or in a Sam Adams commercial.

What are the advantages of new hop preservation methods, and are they the way of the future?

The current gold standard for hop processing and storage is pelletized hops, the rabbit-food-sized cylinders that nearly all commercial and homebrewers use far and wide. It’s important to have a brief understanding of the implications of the pellets before discussing newer formats.

The advantages of pelletizing hops are essentially all based on storage and shelf life. Pelletized hops take up far less space than whole cones do, and they contain the same components — no more, no less. Quantities of hops in many recipes have been calibrated based on the use of pellets, as well, making them user-friendly.

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Drawbacks of pelletization are due to the processing method and can vary greatly from one operation to another. Because the dried hop material is pulverized via hammermill and pressed into the pellet, the lupulin glands break, causing the degradation or loss of some volatile hop oils. The friction of the process can also cause premature isomerization, adding to bitterness without the control of the brewer.  Finally, like cutting into an apple, oxidization occurs more rapidly when the cone is no longer whole, though proper storage will lessen this undesired process.

But pellets are no longer the only option. The growing popularity of “cryo” hops in the Midwest and nationwide grew rapidly this spring when one product, LupuLN2 by YCH Hops, was made available to a wider audience at the Craft Brewer’s Conference. “Cryo” refers to the very cold process by which this product, also called hop power or hop dust, is made.

LupuLN2 is created in a nitrogen-cooled atmosphere, limiting oxidation of sensitive resins and oils. Whole hops are dried and then milled at temperatures below freezing, and then the lupulin inside the gland is separated from the rest of the vegetal matter. Nothing is crushed. This avoids the traditional pelletizing process with its pressure and friction, and in turn, heat. As mentioned above, this heat may be detrimental to the very volatile hop oils thus affecting flavor, and to a greater degree, aroma.

credit: YCH hops press release

credit: YCH hops press release

Here is what YCH Hops has to say on the subject of using the powder:

“LupuLN2 offers brewers approximately twice the concentration of resin content of traditional T90 hop pellets and should be dosed at approximately half the amount by weight. Brewers should note that LupuLN2 will create intense hop flavor and aroma with reduced vegetal and polyphenol flavor contribution because the leafy, plant material has been removed. The flavor profile of LupuLN2 is variety specific, but more pronounced due to the concentration… It can be applied anywhere in the brewery but early kettle recommendations are not recommended for risk of boiling out the intense aroma.” – YCH hops

As of this spring, Cascade, Citra, Columbus, Simcoe, Mosaic, Ekuanot, Loral, and the experimental HBC 682 are available. There is currently insufficient data regarding non-lupulin compounds as compared to whole or pelletized hops including polyphenols and glycosides and their implications in brewing process and beer flavor.

Alpha acid and hop oil content is about twice that of pellets, so a smaller amount is required for the same effect. Furthermore, there is less green matter to absorb liquid so production efficiency is slightly higher. The decrease in vegetal notes and increase in aroma are significant, leading hop powder to be appropriate for dry-hopping.

Josh HareHops & Grain in Austin, Texas, has been an early adopter of hop powder. I visited several years ago and was impressed with their attention to detail and quality. So when I heard about their experimentation with the green dust, I reached out to Brewer and Founder, Josh Hare.

ABV: After experimenting with lupulin powder, especially for dry hopping, have you found that it plays a particular role in your brewing process?
JH: We have found it to be incredibly useful across multiple areas of production, from whirlpool additions all the way downstream to dry-hopping.  Through our experiments we have found that not only are the flavor, aroma, and texture impacts pretty substantial but we also see an increase in yield.  Dry-hopping seems to have the most impact in our trials but we are still experimenting with lupulin powder additions during early fermentation as well as during the latter stages of fermentation.
ABV: Are there times when you find the powder (over pellets or other products) to be almost necessary to deliver your intended product?
JH: I wouldn’t say that we’ve found it to be necessary just yet, but as we continue to trial the replacement of pellets in some of our year-round products we are finding the overall mouthfeel and hop expression is something that we prefer.  As more varieties become available I would not be surprised if lupulin powder makes its way into all of our hop-forward beers.
Stay tuned for the next portion of hop preservation science: hop extracts.

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