An insider’s insight into hemp processing and research

“[After grad school], I consulted with greenhouses across the US, mainly related to ornamentals,” Justice says. “Eventually I started getting calls from cannabis growers – there are a lot of similarities between the two. It worked out quite well.”

All the same, cannabis wasn’t what a younger Dr. Justice envisioned devoting her career to.

“Cannabis was not legal or considered by my fellow peers to potentially be a career path. But oddly, it turned out as one,” she says.

Shortly after she started consulting with cannabis, she was offered a job as VP of Cultivation for a rapidly expanding company in California. She accepted and spent the next three and a half years working in the largest cannabis operation in California at the time.

“I got to experience the whole production,” Justice says. “Everything from seed to sale, extraction, formulation, et cetera. It set me up to be able to do what I do today.”

While Justice was in California, South Carolina passed a bill that allowed hemp production in the state. Initially, only 20 farmers would be allowed to grow. With encouragement from Dr. Justice, her mother applied for one of the permits – and got it.

Now the family grows cannabis on the same land their grandparents used to grow cotton.

“A year or so after they started growing, it was going really well,” Justice says. “We decided I'd move back and we'd take it to the next level. So it's a family endeavor. My brother and sister and mom all work here, and one of my best friends from college.”

Commitment to research and sound science

In an industry dominated by trial-and-error methods and generational knowledge, Dr. Justice makes a point of bringing scientific rigor to her company’s processes. 

Recently, she’s been conducting experiments to dispel myths about drying, curing and other post-cultivation processes. 

As the industry stands now, there’s very little research about post-harvest physiology. Drying and curing methods vary wildly from company to company. There are no standards and little understanding of when each step has been completed, or even why each post-harvest action should be taken in the first place. 

“Curing could be three days for one grower, then it could be 14 days, 30 days for another … there's theory all over it,” Justice says. “[Some growers say that curing] is about removing nutrients, which makes no sense. Or that it's about the exchange of gasses – okay, well, which gasses and how can we make the process better? We don’t know yet.”

In one experiment, Dr. Justice added an array of sensors to a sealed cannabis curing bucket and measured what changes occurred during curing. She measured carbon dioxide, oxygen, ethylene, humidity, and water activity, along with other parameters.

“One really big takeaway from that project was that curing is a homogenization process,” Justice says. “We found that the water activity was lower when we started curing than at the end when we tested again. The theory isn’t that water somehow got into the bucket and made everything a higher water activity. It's that all the buds are homogenizing. A lot of people guessed that, but I think this was the first time that anybody put a number on it – but obviously there’s so much more to learn. We're just touching the surface here.”

Connecting water activity and cannabis

Dr. Justice plans to repeat this experiment, among others, to confirm her findings. Cannabis research is still in its early stages, and there are many topics that Dr. Justice wants greater insight into. 

“Post-harvest is very exciting for me. When I first got to [California], the guys were trying to explain when the flower is dry enough to start curing,” she says. “They grabbed a stem and bent it. At the time, it didn't make a noise, it just bent. And they said, ‘Well, this still needs to dry. Once it's ready, it'll snap.’ For myself and the PhD chemist on staff, that was a little bit mind boggling. We knew there had to be a better way.”

In this case, the better way turned out to be water activity measurements. Dr. Justice found that water activity could give her more precise and actionable measurements than moisture content measurements could. She was soon able to assign critical water activity metrics for different stages of the drying process. She even used water activity to help develop a curing protocol that prevents mold issues while preserving desirable terpenes and enzymatic activity.

“[Water activity] is very important,” Justice says. “For safety purposes, we have to dry it down to a certain level or microbes can grow. But at the same time, we didn't want to dry too quickly because that would volatilize the terpenes. It took quite a few tries to get the plant to stay within those parameters.”

Working for the good of the customer and the community

Considering Dr. Justice’s background and commitment to scientific rigor, it’s no surprise that her company, The Hemp Mine, has earned a reputation for sound research and transparency. 

“It can be very difficult to know who to trust in this industry,” Justice says. “So transparency is something we strive for no matter what we're doing – whether it's what's in a tincture, what the background of this genetic is, or what the data we collect says.”

She delivers on that promise, too. The results of her studies are posted publicly on Slideshare. In addition, she’s partnered with Clemson University to conduct additional research – and influence the next generation of cannabis scientists. 

“Cannabis is so exciting because there's been so little research done,” she says. “I just fell in love with this plant and the opportunities for research.”