CBD oil is the basis of every hemp product. It is a liquid that we get from the plant matter by performing solvent extraction or by utilizing some other method.
Although you can use just about any substance for the process, only a few of them will provide suitable results. Some of them will completely ruin the cannabinoids and terpenes in the plant, while other processes might extract unnecessary ingredients.
This is why Simple Solvents always advises caution. While the solvent extraction process is rather straightforward, there are few things that can go awry. So, not only should you have enough expertise, but you should also utilize the proper liquid for the procedure.
How do we classify extraction solvents for cannabis?
One of the biggest issues with this procedure is that some solvents might be left behind after extraction. Residual solvents could be very dangerous, especially if you used a substance that is not classified as a food-grade chemical.
According to the FDA, there are more than 60 different solvents that we can utilize for the process. All of them are placed in 3 specific categories. Based on the category in which a solvent is placed, we can instantly tell if it's safe or not.
The first category of solvents are substances that we should never use. The second one includes chemicals that are strictly regulated by the US FDA. Lastly, we have a group of substances that can be utilized by licensed companies, but only if you follow certain procedures and standards during extraction.
Most common cannabis extraction methods with solvents
Almost every company in the cannabis business will use a solvent to extract cannabinoids and terpenes from hemp and marijuana.
Besides this industry, solvent extraction is also very common in the pharmaceutical field, food processing, and cosmetic business. We recognize 4 common solvent extractions that you can use for cannabis.
Hydrocarbon extraction method
These substances are very common for botanical extraction. Their potential is seemingly limitless. Back in the day, we relied on numerous types of hydrocarbons for solvent extraction, but given that some of them were very toxic and flammable, we stopped using them.
Some of these restricted hydrocarbons are acetone, ethyl ether, and methyl ethyl ketone. The most commonly used for botanical extraction are pentane, heptane, hexane, propane, and butane.
We use these chemicals because they have low toxicity and are very efficient. While some of their traits are amazing, we still need to handle them properly because of high volatility.
If we exclude the fact that these chemicals can extract some unnecessary ingredients, they are, for the most part, very efficient and desirable. The two main alcohols that we use for cannabis extraction are ethanol and isopropyl alcohol.
Like with hydrocarbon substances, there are several alcohols that were previously popular but are no longer on the list of allowed solvents. For example, toluene and methanol are considered very risky because they can cause optic nerve damage as well as seizures. Acetone is another thing that we need to be mindful of; it can cause neurological damage.
Given there are so many ethanol products on the market, we have a special designation for all of them. This includes FCC-grade, USP-grade, HPLC-grade, and GNS-grade ethanol.
The main reason why you should try this extraction method is because of its high efficiency. You can easily store the substance, and it is also great for laboratories and medical facilities. Lastly, ethanol is very cheap compared to some other solutions on the list.
In a way, CO2 extraction can be categorized as both gas and liquid extraction. During the process, CO2 will change its state. At one point, it will have properties of both gas and liquid. As such, it can have a dual impact on the plant matter.
Although CO2 is very popular nowadays, some other supercritical fluids are banned or strictly regulated. Chemicals such as ethylene dioxide, ethane, nitrous oxide, and benzene can be potentially hazardous to the environment and users' health.
Many companies prefer CO2 extraction. Unfortunately, buying the necessary equipment can be quite costly. During extraction, the solvent will have high diffusivity and low viscosity. It will also be chemically inert.
Terpene wash is a relatively new technique that has shown great results for cannabis. In many ways, it is similar to CO2 extraction. During the process, you can get full-spectrum CBD oil, or you can extract live resins, terpenes, and cannabinoids.
The great thing about the terpene wash is that it completely eliminates any additional processes. You can get any terpenes or resins within 10 minutes. On the other hand, it will take about 30 to 60 minutes to remove cannabinoids.
The best feature of this extraction method is its safety. The process is relatively cheap, easy to use, and you can scale it well as your cannabis business grows.
How to deal with residual solvents?
One of the main concerns with solvent extraction is that you will have to deal with residue once you’re done. While some of these methods try to create oils without any other chemicals, not all of them are ideal in that regard. Despite your best efforts, some solvents might remain in the oil.
Of course, the problem wouldn't be that big if some of these solvents weren't toxic. However, some of them are really troublesome, and cannabis companies take extra steps to ensure that their solvents are safe for use.
Perhaps the best way to deal with extra solvents is by performing headspace gas chromatography. During the process, an expert will take a sample of the substance and dissolve it. After that, the sample will be placed into a headspace vial. Upon sealing the vial, the sample will be heated, changing the liquid into gas.
Next, a certified technician will take approximately 1mm of this gas and place it into a GC detector. That way, the specialist will be able to separate different chemical compounds based on their polarity as well as size.
As the last step, the compound will be placed into mass spectrometer where the solvent will be further analyzed.