491: Brewing Scientists Tom Shellhammer and Cécile Chenot Are Changing How We Think About Older Hops

Over the past two decades, the amount of hops sitting in cold-storage warehouses has more than doubled. While the volume of those stocks is inching back down from its peak in 2022—and while it’s important that the industry has a buffer against climate challenges and bad harvests—a fundamental question remains: Just how useful are those hops two, three, or four years after harvest?

Through a series of research projects and resulting papers, professor Tom Shellhammer and postdoctoral researcher Cécile Chenot of Oregon State University have been working to understand how age impacts hops, and how factors such as temperature, oxygen, and even hop variety drive not just changes in chemical analysis over time, but also have a real sensory impact in finished beer. The results? Surprising, to say the least.

In this episode, Shellhammer and Chenot discuss:

• the myth that fresh is best, and that brewers should use a last-in, first-out approach to hop lots
• pinpointing the chemical markers in hops that actually convey in finished beer
• quantifying the range of variability in hops due to fixed factors such as soil, and to changing factors such as water stress or insect and disease pressure
• how terpenoids degrade at a different rate than thiols in stored hops
• matching analytical chemistry to sensory analysis for a real-world test of the impact of aging
• the vintage effect on thiols in hop lots
• how robust varieties such as Citra and Strata age relative to more delicate varieties
• the impact of oxygen and temperature on hop aging and compound degradation
• variability in packaging integrity within bags of the same hop lot
  

And more.

This episode is brought to you by:

G&D Chillers
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Berkeley Yeast
Here’s a brewer nightmare. It's the night before packaging. You walk into the brewery, straight to the tank. You pull a sample to do a forced diacetyl test and you wait for it in silence. Something feels not quite right. You reach into the water bath and bring the flask to your nose… And it’s a butter bomb. The logistics start running through your head. Do we hold the tank? We have accounts waiting. How many days until it clears? And then you wake up and remember that you use Berkeley Yeast's FRESH™ Chico. It’s got ALDC inside every cell, so diacetyl can’t even form in the first place. Through primary. Through dry hopping and hop creep. Diacetyl stays ultra-low. So you don’t have to add ALDC, or wait for diacetyl to clean up. And most importantly, you don’t have to wake up in a cold sweat, worrying about scary stories like these. FRESH™ Chico is now available in dried bricks for as low as $88 at berkeleyyeast.com.

PakTech
This episode is sponsored by PakTech—delivering craft-beer multipacking you can trust. Our handles are made from 100 percent recycled plastic and are fully recyclable, helping breweries close the loop and advance the circular economy. With a minimalist design, durable functionality you can rely on, and custom color matching, our carriers help brands stand out while staying sustainable. Trusted by craft brewers nationwide, we offer a smarter, sustainable way to carry your beer. To learn more, visit paktech-opi.com.

Indie Hops
Oregon hop country is heaven to world-class lager varieties, and Indie Hops is proud to have introduced Oregon’s newest lager hop, Lórien, in 2022. Lórien is in a growing list of beers that have found their way to the podium and—more importantly—into the hearts of lager lovers across the country. Discover Indie Hops Lórien. (Side effects may include rampant festivity, sales bumps, and exceeded expectations.) Indie Hops—Life is Short. Let’s Make It Flavorful.

Midea 50/50 Flex
If you’re like many podcast listeners, you’ve got a lot of beers at home, and your regular fridge is at capacity. Enter the Midea 50/50 Flex—the industry’s first dual compartment three-way convertible freezer. Here’s what all that means for you: options! The 50/50 has the power to be all freezer, all fridge, or a little bit of both. But you’ll probably want to use those 20 cubic feet as a massive, garage-ready beer fridge. You can also change which side the door is on or how you want the shelves to be arranged—the 50/50 totally flexes to fit your life. Plus, it’s designed to maintain a stable temperature even in non-climate-controlled conditions—so you can crack a cold one even on the warmest days in the man cave. Take your garage to the next level! Check out Midea.com/us/ to get more info about this game changer today.

Briess Malting
Briess Malting has been supplying craft brewers with the highest quality base and specialty malts since the early 1980s. As Briess celebrates their 150th Anniversary this year, they are proud to remain a fifth-generation, family-owned company. They love to support the creativity and passion in craft brewing that results in amazing beers. All Briess malts are made in America, so you can count on a reliable supply chain. Barley is sourced from 300 growers in the Bighorn Basin of Wyoming and Montana. Plus, technical support is available through their Center of Malting Excellence. With 150 years of malting expertise, check out why so many craft brewers trust Briess for their specialty malt at BrewingWithBriess.com.

John I. Haas
Brewing has always been about creativity—but at scale, it’s about control. For more than 100 years, Haas has worked with brewers to push what’s possible with hops. And today, that means more control over flavor, efficiency, and consistency. Our advanced products help you get more out of every brew—more flavor where you want it, less waste in the process, faster tank turns, and results you can count on—batch after batch, year after year. From next-generation pellets, such as LupoCORE and LupoMAX, to innovations such as Incognito and Euphorics, our products fit seamlessly into your process—from the hot side through fermentation to the cold side. Advanced hop products are just one of the ways Haas is growing the future of brewing. Learn more at johnihaas.com.