Cannabinoids (including CBD)
Hemp grown for the CBD will be harvested when CBD content is maximized and THC is at or below the 0.3% threshold. Many growers look at the color of the trichomes to determine when to harvest. Monitoring THC and CBD levels with chemical testing should be the driving factor to determine the harvest date. There is instability in hemp genetics, a factor in monitoring cannabinoids when you are assessing cost of production.
Growers are using different technology to harvest their CBD hemp and harvest method will likely depend on the size of the operation. Hiring laborers to hand-harvest is a common method. Some growers are using mechanized harvesting. Growers in tobacco production states are using hemp-specific harvesters that typically cut one or multiple rows of whole plants. Growers that are producing at a large scale are using combines to cut the upper portion of the plant. This method is not very common.
Most processors are requiring that plants be dried prior to arriving at an extraction facility. In Kentucky, growers are using existing tobacco barns to hang and dry their hemp. There are mechanical drying machines that run forced air over the hemp and facilitate quick drying for those that cannot hang dry. If you plan to hang dry, check the load-bearing capacity of your structure.
After the plant material is dried, some processors require that they receive material in super sacks already chopped or pelletized, while other processors want hand-shucked hemp material. Each processor will have their own specifications about how the material should be harvested, dried, and shipped to them.
Processors can differ greatly in how they extract CBD and other cannabinoids from raw hemp. Alcohol, hydrocarbon, and supercritical CO2 are all common methods of extraction.
Winterization helps separate waxes and lipids from crude oil. This is typically done by mixing crude oil and ethanol and then exposing the solution to sub-zero temperatures for a specific time.
Distillation is used to purify the extract further.
Isolation is used to refine the distillate to a pure cannabinoid, in this case, cannabidiol (CBD).
The formulation is necessary to make CBD oil that has the correct concentration of CBD in the bottle. Different carrier oils are used and sometimes flavors are added.