Most everyone nowadays knows that the primary difference between hemp and marijuana is that marijuana contains higher levels of THC while hemp contains higher levels of CBD. Although hemp and marijuana are both in the taxonomic family Cannabiceae (they can be described as “cousins”), they have developed unique genetics and characteristics that distinguish them.
Both CBD and THC come from the same precursor compound, cannabigerolic acid (“CBGA”.) Cannabigerolic acid in hemp synthesizes into CBDA whereas research has shown that marijuana has a nonfunctioning copy of CBDA so it focuses all its cannabinoid production on THCA. Specific enzymes in the plant break down CBGA and “direct” it toward becoming either THCA, CBDA or CBCA (cannabichromenic acid.)
Decarboxylation, a process that simply involves heating the flower material, changes the THCA into THC, CBDA into CBD and CBCA into CBC (at present, there are not a lot of known uses for CBC, but researchers are searching.) Decarboxylation is a bit of a tricky science…heat the plant material too much and you burn off beneficial terpenes…don’t heat it enough and you leave some CBD in the flower in the form of CBDA.
The amount of CBDA in a particular hemp plant increases as the flower matures. As a result, farmers want to leave the plant in the ground as long as possible to maximize the CBDA content (and, as a result, the CBD content.) Unfortunately, the THCA level increases along with the CBDA. So…it’s a bit of a trick to harvest at just the right time. In states like Alabama where recreational marijuana is not legal, if a crop comes back as too high in THCA (commonly referred to as “hot” in the industry), it is considered marijuana (as defined by the 2018 Farm Bill) and must be destroyed. It’s important to test the crop multiple times throughout the growing season to monitor the THCA/CBDA ratios.