The 2014 hops harvest is firmly in the rearview mirror, and, like squirrels caching stores for the winter, many of us are stocking up on fresh hops to sustain us until next autumn. Keeping a few common varieties on hand gives you flexibility to homebrew spur of the moment, but maintaining a stash of Humulus lupulus does mean paying attention to a few storage considerations.
Keep Hops Away from Oxygen
Oxygen is enemy number one in the fight to keep your hops fresh, as it is with pretty much every other aspect of homebrewing (yeast reproduction excepted). Oxygen degrades the precious oils that are responsible for the wonderful flavors and aromas that hops deliver, and over time, oxidized hops take on a distinctive aroma that’s not unlike aged cheese (you’ll know it when you smell it).
Oxygen also breaks down the alpha acids that deliver bitterness, which is why you’ll sometimes hear about the hops storage index (HSI), which quantifies how quickly different hops varieties lose their bitterness with time. The HSI attempts to quantify how much of the available alpha acids remain after six months’ storage. An HSI of 30 percent means that 6 months after harvest, the hops theoretically possesses 70 percent of its original bittering potential.
Keep Hops Away from Light
Hops should not be stored in the light, despite that attractively illuminated display at the homebrew supply shop. Light prematurely ages hops, just as it does people. Keep your hops in the dark to ensure quality.
Keep Hops Cold
There’s a reason your homebrew supply store keeps its hops in the fridge (even if the light is on): Heat causes hops to age more quickly than if they’re kept cool. In fact, keeping hops in the freezer prolongs their life by four times or more. And since hops are dried after picking and have high levels of oil, freezing won’t damage them the way it does, say, fruit skins.
Keep Hops Compressed
When I brewed my first batch of beer, I remember pulling what appeared to be little packets of rabbit pellets from the boxed kit and feeling somewhat horrified that these were the “hops” with which I was meant to brew. I had pictured bags of bright green little pine cones that I could enthusiastically dump into the kettle, just like they do in the commercials and documentaries.
Pelletized hops might not be much to look at, but they’re generally a much more practical choice than whole cones, especially if you plan to keep them around for a while.
- Pellet hops last longer than whole leaf hops because there’s less surface area available for oxidation.
- Pellet hops require a fraction of the space that leaf hops do.
- Pellet hops are usually easier to measure.
What To Do?
Given these considerations, the ideal storage environment for your hops is in oxygen-barrier vacuum bags in the freezer. Invest in a home vacuum sealer system and consider using mylar-lined plastic vacuum bags. If you can’t get your hands on mylar (or don’t want to spend the money), regular plastic vacuum bags will work just fine unless you plan to keep those hops for a really long time, say several years.
When you take the necessary precautions to keep your hops in tip-top shape, they’ll reward you all year long. Then when hops harvest 2015 rolls around, you’ll have a great excuse to brew up a few double IPAs to make room for the new batch!