Unlocking the Freshness by Freezing


Just once a year, the world’s hop farmers harvest their crops, which are then immediately dried, packed and delivered to breweries. Only during this period do brewers get the chance to make a beer with the fresh flower before its leaves are dried and the oils dissipate. 

Brewing with hops that have been kilned versus those that have been just picked but not dried is like comparing canned and fresh vegetables. An undried hop cone has about 80 percent moisture content that’s taken down to less than 10 percent with kilning. Since hops are immediately processed to remove leaves and laid out on drying beds, the fresh ones must be used usually within 24 hours of picking (after that, they start to decompose). 

However, there’s little research or even anecdotal experience to call upon when brewing with fresh hops. The bright yellow lupulin locked inside is like flakes of gold found in a stream.


Coaxing these subtle, fragile flavors out of a freshly harvested cone is harder than it may seem. Methods vary brewer to brewer. The most common way to get the most out of fresh hops is to add them to the brite tank at a rate of eight times the amount of hops you’d normally use. This process is relatively untested, labor heavy and likely not very cost-effective. 

Portland’s Breakside Brewery might have been the first to experiment with a new method of processing fresh hops by freezing them with liquid nitrogen. “The idea came to me in early 2014,” recalls Breakside brewmaster Ben Edmunds. “ I had discussed the idea of getting more surface area contact and varietal-specific character in our fresh hop beers, but we hadn’t really discussed a method for doing it.” 

Edmunds was on a trip to Seattle with Seth Barnum of True North Ale Company in Massachusetts, and the two were discussing fresh hops. “I kind of said ‘What I really want to do is just shatter the hops open,’” Edmunds describes, “and I had this memory of an elementary school science fair where I watched someone shatter a rose into a bunch of pieces after dipping it in liquid nitrogen. So, that’s where the idea started.”

Early attempts to make fresh-hop beers tended to result in flavors reminiscent of grass and vegetables that could be off-putting. When they’re at their best, the fresh-hop flavor, though, is a brighter, fresher expression of the hops and their characteristics: floral, fruity, piney, even oily. Brewers still don’t have any studies into why this character is so hard to capture in a fresh-hop beer, but Edmunds has a theory. 

“In my estimation, it was because the way most people handle fresh-hop beers doesn’t allow them much access to the lupulin glands where so many of the key aroma and flavor constituents are held,” he says.

“By freezing and breaking the hops up, it helps us get as much out as possible,” says brewer Conrad Andrus of Portland’s Culmination Brewing. He’s also started using nitrogen to freeze hops. “We have seen a pretty significant impact from this over last year when we just floated wet hops in bags.” 

Cascade Brewing experimented with this technique in 2016, and head brewer Kevin Martin believes that “with greater exposure, the beer more effectively extracts the clean hop aromas found in the lupulin glands that might otherwise go underutilized from being locked inside the wet hop cone.”

The process goes a little something like this:

Freshly harvested, whole cones are picked up at the farm.

After being brought back to the brewery and loaded into a container (55-gallon drums at Breakside), they are sprayed with liquid nitrogen and freeze. Brewers then crush the crunchy icy hops with a sanitary tool (Breakside uses a soil tamper) and then thaw them out.

The crushed hops are added to clean bags and loaded into an empty brite tank where already fermented beer is poured in. The beer absorbs the fresh-hop flavors for as long as the brewers deem desirable.

The beer is kegged or bottled and carbonated and ready to be sent out to drinkers.
Edmunds says the process creates a lupulin dust as the hops warm back up and it doesn’t cause any freezer burn. “They still have the soft qualities of freshly picked cones,” says Edmunds. “I think that we get a good mix of the ‘green character’ people expect from fresh-hop beers, but we also get a lot of softness and hop-specific notes.”

The nitrogen method is gaining steam outside Oregon, with breweries like Powell Brewery in Vancouver, British Columbia adopting it. But there’s no hard evidence it’s the best way to use fresh hops and Cascade went back to traditional methods after experimenting once. 

“We can only anecdotally suggest that it was indeed a cleaner, more effective process. We have no data or sensory panels to back that claim up,” says Cascade’s Martin, who adds they also have had great results from simply soaking whole cones in beer. “I still don’t doubt the theory that freezing and shattering the cones can lead to greater hop aroma, but determining whether the aroma is actually cleaner or simply more intense is yet to be determined through our experience here at Cascade.” 

Martin recommends every brewery try it at least once, and would like to see some blind sensory panels on the same beer brewed with different methods. •

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March 1, 2019

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Ossie Bladine  |  obladine@newsregister.com

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