Cannabis Chemistry: What To Know About Evaporation Post-Harvest
After growing and caring for cannabis during harvest, the last thing a producer wants to do is ruin the finished product.
As margins shrink in a hyper-competitive industry, cultivators would be wise to ensure their flower stands out for the right reasons; and moisture retention is the biggest key. Paying attention to humidity control post-harvest makes a big difference, particularly with maintaining quality and value, which can help separate one cultivator from another.
While some may rush to harvest flower for processing, the ones who realize the importance of moisture retention will create a better overall product, and, thus, impact retailers, consumers and, ultimately, the cultivator's bottom line.
How Insufficient Humidity Affects Cannabis Chemistry
More than 100 cannabinoids have been identified in the cannabis plant, and a growing body of scientific research is revealing how they interact with our bodies in profound ways, beyond just the well-known euphoric effects of THC.Meanwhile, terpenes, the organic compounds that create a plant's distinctive aroma, are also receiving more scientific scrutiny, as they're believed to play a significant role in the therapeutic effects of cannabis. The interaction of the various plant compounds is what researchers have dubbed the "entourage effect" -- this complex interplay of cannabis components within the body's endocannabinoid system.
When harvested cannabis dries too much, trichomes become brittle, fragile and can break off. Likewise, terpenes also evaporate when trichomes are exposed to conditions that allow oxidation to occur. Once lost, neither trichomes nor terpenes can be recovered, even if the flower is rehydrated. Any loss of particular compounds alters the chemical composition of cannabis flower and can harm its therapeutic value, which is a concern for many consumers. And with cannabis buyers far more sophisticated in their knowledge of cannabis strains and quality, this is an important factor cultivator's must consider.
Moisture Loss Equals Money Lost
Dry cannabis flower undercuts profit margins for marijuana cultivators, that's a fact. Flower that's too moist is prone to hazardous mold and microbial growth, so many cultivators, processors and packagers finish their cure and then store, package and sell their cannabis in a state that's unfavorably dry.
At Boveda, we've found this to be true as well. Through an analysis of 72 flower samples sold in five legal state markets, nearly 70 percent of the samples came out overly dry and below the optimal relative humidity (RH) range of 58-62 percent. According to Boveda research, a mere 5 percent dip below the optimal RH threshold eliminates six pounds per every 1,000 pounds of cannabis flower. At $5 per gram wholesale, that works out to upwards of $13,500 in lost revenue -- and that's just at a 5 percent humidity drop.
While wholesale prices vary, this example illustrates the broad impact on the bottom line. So unless a company wants profits to literally evaporate into thin air, establishing proper humidity control is an absolute must.
How Two-Way Humidity Control Works
Despite the previously mentioned concerns, excessive post-harvest evaporation is entirely preventable. Two-way humidity control solutions add or remove water vapor from a package or container to maintain a constant, predetermined RH level. This ensures a consistent level of moisture weight inside the cannabis flower.
By utilizing specialized humidity controls, producers can keep the cannabis flower in the "just right" Goldilocks zone, which helps preserve quality and weight, while limiting the risk of mold and microbial growth that comes with an overly humid environment.
The potential benefits are notable, too. According to a third-party lab study which analyzed flower cured with two-way humidity control solutions designed to maintain RH at 62 percent, the cannabis retained 18 percent more terpenoids, and 23 percent more cannabinoids compared with a control. That's a significant difference in quality.
Post-harvest humidity control holds the key to preserving quality, profits and peace of mind. Amid volatile wholesale prices, cultivators must maintain production quality standards in order to retain customers and continue to grow as a business.