The process of extracting desirable odor compounds from plant matter—think: roses, lavender, or other prefered fragrances—is rather basic. It produces the results it does because compounds can be distilled at temperatures below that of the boiling points of individual constituents, preserving their characteristics. Steam is pumped through the matter under pressure, softening the cells, freeing essential oil and turning it into vapor. After cooling, the steam condenses into water and the vapor into essential oil. Because the oil is most often lighter than water, the two may be easily separated.
Avicenna, a Persian polymath who lived from 980 to 1037 A.D., is credited with being the first to use steam distillation for isolating essential oils from flowers, starting with rose water. Although the process now has multiple other industrial uses, it remains the most common method for producing aromatherapy-grade essential oils.
This is where hops come in.
Brewers understood the value of the volatile oil in hops hundreds of years ago. In 1788 in England, William Kerr patented a device that used a pipe to collect vapor leaving the kettle, brewery workers cooled and condensed the vapor, added the hop oil they collected to the still boiling wort, saving the water for the next mash. By the 19th century, brewers could purchase commercially produced essential hop oil, though nothing in brewing literature indicates many used oil extensively.
Such potions were not on the radar of most American craft brewers until recently, nor did it seem they deserved to be. “Brewers who have evaluated hop essences with hope of producing ‘engineered’ hoppy beers have been disappointed,” Larry Sidor, then head of brewing at Deschutes Brewery and now owner of Crux Fermentation Project, wrote in in 2005 for MBAA Practical Handbook for the Specialty Brewer.
And then along came Sierra Nevada Brewing Company Hop Hunter IPA in 2015, brewed with “farm distilled hop oil.” The brewery put the words right on the label, and in retrospect that turns out to be more important than the trademark ruckus that Tony Magee of Lagunitas Brewing raised about that beer. Sierra Nevada changed perceptions by adapting machinery previous used to distill mint plants, making it possible to brew beer year round with fresh hop aroma and flavor.
In Montana, Tom Britz read about this and thought of a conversation he had a few years before with a county extension agent about using defunct mint distilleries to process hops. What seemed as outlandish when he was first starting Glacier Hops Ranch suddenly looked like an opportunity.
In North Carolina, Daniel Meehan, a Tesla Motors photovoltaic and storage system designer by day and would be plant distiller in his spare time, had a different thought when he learned about what Sierra Nevada was doing.
“Son of a bitch.”
These are not snake oil salesmen knocking at the brewery door. “In an industry and a beer scene where hops continue to be a driver in beer innovation, I think it’s a wonderful product,” New Realm Brewing co-founder Mitch Steele said during a presentation about “Understanding Pure Distilled Hops Oils” at the 2018 Craft Brewers Conference. That presentation focused on Hopzoil, which Glacier Ranch developed, but also provoked interest in both what newcomer New River and older established companies are offering. Most brewers did not realize that Hopsteiner, which has been around since 1845, sells steam distilled oil produced once a year at harvest.
Meehan knew none of the history of distilling oil from hops when he decided it could be a business, and if he had more money to invest at the outset, New River Distilling might not now offer smaller breweries an option to turn hops they already own into oil that magnifies already bold, intense aromas and flavors. He solved a problem he didn’t know existed.
Meehan majored in renewable energy at Appalachian State University in North Carolina, focusing on fluid processing. Still in school, he worked as production manager at Foothills Bio-Energies. He took a job of Tesla after he graduated, moving to Colorado with his wife-to-be, Breanna. Because she urged him not to forsake his love for fluid processing, he began visiting cannabis extraction labs in his spare time. He’d become captivated by hops when he helped grow them on a farm where he lived while attending Appalachian State, but in 2014 in Colorado, cannabis processing was the growth industry—and the facilities were excellent places to learn about supercritical CO2 extraction.
Liquid CO2 extraction of hop pellets produces the most pure whole resin and oil extract. The extract has many advantages over whole hops or pellets—including reduced costs for shipping and storage, uniformity, stability, better utilization, and reduced wort losses.
Meehan turned his attention from extraction to distillation because he recognized the concentration of some of these prized compounds was reduced during supercritical extraction, and, he admits, because it was less expensive to start assembling his own system. He began in earnest after returning to Boone, NC in January 2015, still working for Tesla, though remotely.
“The ideas started flowing. I built the first steam generator,” he says. He read about what Sierra Nevada was doing, but was headed down his own path. He took what he learned from large biodiesel systems to design one that was “similar, but not similar.”
He went through five different prototypes. He built different steam generators, changed the way steam passed through the extraction vessel, and also how oil was collected. There were missteps along the way. During a session in which he was working on a steam generator design and trying to figure out how to manage a certain flow rate through the extraction vessel he decided to see what limits the hop pellets could withstand in relation to the oil output. He didn’t realize he had isolated a pocket of steam in the system, and before he knew it a burst of steam caused the machine to flip over.
“It was the classic mad scientist image,” he says. “Or dad blowing himself up in the basement. I was covered in pellet dust, head to toe. Steam billowed out of the shop I was working in. I’m not sure what the neighbors thought I was doing.” But the experience turned out to be a catalyst in figuring out exactly how to control steam through the extraction vessel and ultimately through the heat exchanger.
When Meehan met Kiever Hunter, a Boone native who had left the mountains to attend North Carolina-Chapel Hill before returning home, he immediately was impressed by how much Hunter knew about beer. Hunter, the brother of Meehan’s wife-to-be’s best friend, was struck by how passionately Meehan spoke about a process for distilling hops and other plant matter.
“I probably looked at him like he was crazy,” Hunter says.
Meehan knew he needed to find a partner. The day after he invited Hunter to see what he had finished at the time Meehan gave him a company email, and Hunter began cold calling brewers via that address. The two comprise the entire company for now.
At the outset they could process two pounds of hops at a time and 22 in a day. “Then the first big order came in, 176 pounds. We thought, ‘Oh, shit, what are we going to do?” Meehan says. They recently struck a partnership deal with the Hempleton Group, a North Carolina company that has invested in multiple cannabis projects. New River Distilling will soon be able to distill 1,500 pounds of hops per week and to extract iso-alpha acids post distillation. In addition, the equipment will be used to isolate hemp terpenes and extract CBD compounds for hemp farmers around the country.
Greater capacity means they can process larger orders, but also more smaller ones. They also can customize the blend of some odor compounds. “The idea behind what we do is versatility,” Hunter says. Distilling hops that breweries already own became another aspect of versatility, turning what might have been a flaw became a feature. Meehan originally intended to acquire pellets, distill them, and sell the output, but that would have required more investment. By providing hops that will be turned into oil, brewers can balance what they already have under contract.
The term “essential oil” can be traced back to quintessence and Aristotle’s fifth element, aether. Medieval alchemists sought to isolate what was considered the life force of plants using distillation so they could incorporate it in medicine and elixirs. Modern chemists think in more specific terms, and what brewers consider essential has changed in recent decades.
Hop oil makes up to 4% of the hop cone. Between 50-80% of the oil is hydrocarbons, 20-50% oxygenated hydrocarbons, and less than 1% sulfur compounds. In 1976, three chemists at the Brewing Research Foundation in England patented a process for “an improved method for making hop oil.” Their research showed that oil produced by their new process contained up to 90% less sulphur-containing compounds than other distilled hop products. That was an “improvement” because those compounds produced odors brewers did not want in the beer, ones often described as “catty” or “blackcurrant.”
Not until the 21st century did researchers determine that some sulfur compounds, also known as thiols or mercaptans, may contribute to the bold, citrus, and tropical aromas currently in vogue. Such thiols are measured in parts per trillion, the instrumentation needed to determine levels is very expensive, and few laboratories have the equipment needed—the result being that brewers know broadly which hops (Citra, for instance) may contain more thiols and which less (Saaz).
Nobody has measured the level of a specific thiol in pellets made from any given variety versus what makes its way into distilled oils. Instead, brewers must rely on what their senses tell them, and so far they’ve found oil from distilled hops seems to contain the same thiols as pellets. Nonetheless, contributions from oils, including hydrocarbons and oxygenated compounds, may be much different.
“What I’m seeing, was blending it with pellets, it was a synergistic effect,” Steele says. “There was a lot more going on.”
Scott Kimball at Triple C Brewing in N.C., one of New River’s first customers, agrees. “Keiver just popped into the door with some samples and they smelled good,” Kimball says. He used oil first in pilot batches, has experimented with oils distilled with almost every hop the brewery uses, and since made oil part of regularly produced beers, including mainstay 3C India Pale Ale.
Although the beer won a medal at the 2015 Great American Beer Festival, he isn’t afraid to have it change from batch to batch. “We are inching toward a better product. This hop oil is going to help us get there,” he says.
Like Steele, he has noticed beers made with distilled oil seem to maintain their aroma and flavor longer after being packaged. Hunter and Britz have made such anecdotal endorsements part of their respective sales pitches. Either can recite numbers illustrating financial or environmental benefits, but they understand brewers are focused on aroma and flavor.
“It’s really a new product, really a new category,” Britz says. Sierra Nevada brewed its first fresh hop, that is with hops taken directly from the field to the kettle without being dried in a kiln, in 1996. When founder Ken Grossman began a conversation with a mint farmer in Yakima Valley in 2012 it set in motion the opportunity to replicate brewing with the essence of unkilned hops year round.
“What they did, their goals, were very different,” Britz says. Glacier Hops Ranch is located in Montana’s Flathead Valley. “There used to be 15 steam distillers. Now there is one mint grower left,” Britz says. Tapping into the same technology as Sierra Nevada was a starting point. “I did some research with our Montana State University Research Station here, and we did some different things with fresh hops than they did with mint, and we stumbled over our feet and eventually figured it out,” he says.
“We are seeing brewers approach (Hopzoil) from so many angles. There’s a lot of evolution. It’s really, really cool to see,” he says. “It’s really been interesting to listen to brewers.”
About 15 years ago breweries that would call themselves craft eased into another advanced hop product, CO2 extract. Vinnie Cilurzo at Russian River Brewing was the first to speak openly about using extract. Initially he hopped Pliny the Elder only with pellets. He didn’t like grassy, chlorophyll flavors he attributed to sheer hop mass. Following a suggestion from Gerard Lemmens at Yakima Chief, he replaced pellets with extract for the bittering addition.
“We kept it secret for the first few years,” Cilurzo says, “but Gerard twisted my arm.” Cilurzo gave Lemmens permission to publish the information in a Yakima Chief newsletter. Scores of other small breweries soon began to use CO2 extract as a result.
“It’s such a personal decision,” he says. “It’s philosophical.”
Steele thinks similar philosophical discussions about hop oil would center around “Is this big brewery stuff?” It isn’t, in his mind. “It’s not really about speeding up the process or reducing cost. It’s more about providing alternatives and new flavors.”
You might say it’s creative, fluid processing. That results from creative fluid processing.