We often get asked “How much THC or CBD will your machines produce?” and the answer is “it varies”, and this is due to several variables: the type of machine you choose, the parameters that are chosen, the post-processing technique, but the most important variable is the source material or biomass. Poor quality biomass will give you poor quality extract. Worse though, is if the biomass is contaminated with pesticides or other contaminants, the extract will be a concentrated version of the source material. For this reason alone, it’s extremely important to get the source material tested before you begin extracting, and also afterward – if there are trace amounts (but undetectable in a test) of contaminants in the source material, these will be present in the extracted oil, since it’s in concentrated form.
Let us break down the term “biomass”. The cannabis or hemp plant has “buds” or “flowers” that contain the bulk of the cannabinoids and are the most valuable part of the plant. These buds are only found on female plants and they contain trichomes which are the sticky nodules on the plant that host the THC and CBD (as well as other cannabinoids but for the sake of brevity, we’ll stick with the two main ones!).
Preparing For Extraction & Creating Final Biomass
Before extracting, the plant is dried (unless extracting live rosin, in which case, wet plant material is preferred), and usually the buds are separated from the rest of the plant material. Because of their high value, they are usually sold as dried flower in dispensaries, after all excess material is trimmed off them. This trim material is what’s usually used in extraction, however (another variable!), cultivators sometimes grow low grade hemp or cannabis and blend the entire plant (buds and all) once it’s dried and cumulatively, the extract is roughly 5-15% potency. By comparison, high quality source material has 15-25% potency. The blended material, containing flower, stalk, trim, and leaves is considered “biomass”. Before extracting with an Apeks Supercritical CO2 system, it should be completely dried (some processors use a freeze dryer to remove every drop of moisture) and ground up to coffee ground consistency.
Obviously, bulk raw material containing lower amounts of CBD and THC is cheaper to source than high grade material. Even purchasing the byproduct of high-quality material could be prohibitive so processors are exploring more economical ways to produce good quality oil.
How to Identify Good Biomass
Test a representative sample
Identifying good biomass when you are simply looking at it can be tricky but not impossible. The first step is to make sure that the material is properly homogenized (mixed up) and you are testing a representative sample of the entire batch. It is a good idea to closely examine the buds to determine trichome density. The trichomes produce the cannabinoids so a greater density of trichomes means a higher density of cannabinoids. Terpenes are also found in high quantities in the buds.
Terpenes are what give the plant the flavor and odor and they are a very high-quality part of the plant. Most processors extract terpenes first (they are fragile and will not withstand high pressure and temperature), and then set them aside. Once the rest of the biomass is extracted, then purified (distilled or refined to remove fats, waxes, lipids, and other undesirable parts), the terpenes are added back in to create a comprehensive extract. Think about a wine connoisseur – they will always test the smell of the wine before taking a sip. They are smelling terpenes, and the denser the terpene profile, the higher the quality of wine. In the same way, a plant that is high in terpenes is more valuable because it can create a full spectrum extract. Full spectrum is extract that contains all the compounds of the plant, all of which contain some beneficial properties and are more effective taken together, rather than taken in insolation. Avoid any biomass that smells even slightly moldy!
Mold and pests
Like any other plant material, cannabis and hemp can get infected with mold or pests, particularly if not dried or cured properly. Bugs like aphids, spider mites and mealy bugs can contaminate the plant and result is low quality biomass, which should be avoided at all costs. Look for white or gray looking fuzzy specs, or evidence of webs from spiders. Any sort of white fuzzy substances could also be an indication of mold, while powdery mildew leaves a flour-like residue on plants. Any indication of bug or mold contamination means low quality material that should not be used.
Look at the biomass and identify plant parts
It is important to understand the ratio of buds, leaves and stems/stalks in your biomass. Each component has a different cannabinoid density and a biomass high in stems/stalks will have little to no cannabinoid content, while a high level of buds means a higher potency since these are higher in cannabinoid content. Most biomass will contain a large amount of leaves – these are what are trimmed off the bud, but regular leaves do contain some trichomes as well. Stems and stalks are the lowest value part of the biomass.
The color of the biomass should be a deep and healthy-looking green. Avoid biomass with yellow and brown material – that is an indication of old or badly dried plant material. The cannabinoids will not survive long after the plant is picked so it is important to cure the plant properly to avoid degradation of any cannabinoids.
Testing is absolutely vital – without a laboratory test, there’s no way to tell if the plant material contains heavy metals, pesticides, or even high/low cannabinoids. As stated previously, testing before and after extraction is ideal – before, to avoid issues with source material (you wouldn’t move ahead with biomass that’s heavily contaminated with heavy metals) and after, to ensure nothing was missed and is now in concentrated form in the final product. Hemp is particularly susceptible to contamination because it pulls out harmful material in the soil, so even two years after pesticide was used, the hemp plant will pull out remnants from the soil. Trace amounts in the biomass mean elevated levels in the concentrate.
As the industry gets more regulated, testing is going to become a requirement, so it is a good habit to get into, from the start.
Ideally processors will cultivate their own feedstock, so will know exactly what they are getting. However, vertical integration is expensive and not always an option. Processors need to be savvy when purchasing biomass from third party sources. A laboratory test is the only way to ensure cannabinoid levels and to make sure there are no contaminants. It is far more economical to have the material tested before extraction, than to move ahead with the extraction without testing and try to sell contaminated product. As regulations are rolled out country-wide, products intended for human consumption will need to meet the same standards as any other product on the market today.