CBD products are becoming increasingly popular, leaving many consumers wondering where to start. While it’s true there are almost more options than you can count in the world of CBD today, there’s one important factor everyone should consider before buying and consuming a hemp product: How it’s made.
Understanding How the CO2 Cannabis Extraction Method Works
There are, of course, a few reasons why CO2 extraction isn’t the right method for everyone. Below are a few of the cons to consider…
Cons of CO2 Extraction
One of the most trusted ways to extract CBD from cannabis or hemp, the CO2 extraction method is categorized into three different types: supercritical, subcritical and mid-critical. Most professional and reputable companies use the CO2 extraction method simply because it’s the safest way to create the purest product.
Once you have the liquid CO2, the next step is to increase the temperature and pressure past the point where the liquid becomes ‘supercritical.’ This term means the CO2 can now adopt properties halfway between a gas and liquid simultaneously. Effectively, the supercritical CO2 can fill a container (like gas) while also maintaining density (like a liquid). When CO2 is in its supercritical state, it is ideal for chemical extraction. This is because it won’t cause denaturation or any damage that would make the CBD unfit for human consumption.
Put on your gloves and eye protection, chop up the cannabis buds into small pieces and place it in the bucket. Cover the plant with the dry ice and leave it for 3 minutes. It is best only to fill the bucket halfway. This process causes the freezing of the trichome resins. Fit the 73-micron bag over the bucket and shake the ice & plant combo for about 4 minutes; this knocks the frozen trichomes off.
Moreover, CBD is known to inhibit the functioning of the FAAH enzyme that directly acts on the CB1 receptor and enables THC to produce its psychoactive effect. CBD has established global interest among industry specialists, and its discovery has prompted medical experts to take a closer look at the benefits.
Mid-critical is simply a general range between subcritical and supercritical. Some companies combine supercritical and subcritical to create a full-spectrum CO2 cannabis extract. They use the subcritical extraction method to separate the drawn-out oil and the very same plant material using supercritical pressure. The oils are then homogenized into one, which creates an amalgamated oil. This is known as the CO2 Total Extraction Process.
Pros and Cons of the Olive Oil Extraction Method
2 – The Olive Oil Extraction Method
If you are reading this article, you likely know what THC is. Delta-9 tetrahydrocannabinol is the most psychoactive ingredient in cannabis, and until recently, was by far the best-known.
This form of extraction involves low temperatures and low pressure. Subcritical extractions take longer than their supercritical counterparts and also produce a smaller yield. While it retains the terpenes, essential oils, and other sensitive materials, it doesn’t extract larger molecules such as chlorophyll and omega 3 and 6. The benefit of subcritical extraction, however, is that it is less likely to damage terpenes.
Therefore, the three factors chosen for variance were:
Response 1: %CBD recovery
The parameters used to assess extraction efficiency were:
When analysed statistically, the CO2 flow rate is shown to have largest effect on CBD recovery. Extraction pressure had the least overall impact to CBD recovery even when combined with other factors (Table 2 ).
Supercritical carbon dioxide extraction of cannabis biomass
We were not interested in assessing the capability of the system to separate different fractions and so the extract in each cyclone was combined prior to analysis. For each PD run the baskets were packed with the cured cannabis biomass (1.0 kg). The material was manually packed tight into the baskets using a custom-made stainless-steel plunger. The remaining space in the basket was filled with food grade glass marbles. The extraction programs were set up as described in Table 4 .
DOE is commonly used to optimise engineering processes and to determine which process inputs have a significant effect on process outputs. In a factorial design each variable, or factor, is investigated at predefined levels. With a two-level factorial design each factor can be one of two values. For continuous variables, this is a high and a low level of the variable under investigation 22 . Importantly, the methodology can also determine if there are interactions between the factors in the process. This allows for more rapid optimisation of processes than if single variables were considered independently. This methodology has been used to investigate factors important in extraction of biomaterials. For example, Prasad et al. explored the effect of five factors (pH, ethanol concentration, temperature, time and liquid to solid ratio) on four responses (extract yield, antioxidant capacity, phenolics and flavonoids) for the extraction of the Malaysian fruit, Mangifera pajang 23 . Lee et al. analysed similar factors to optimise the recovery of phenolics, flavonoids and anti-oxidants from palm-kernel by-products 24 . A review of the literature by Reverchon and De Marco demonstrated that CO2 flow rate, extraction pressure and extraction time are the critical parameters in SFE for the extraction of natural materials 25 . Therefore, these were the factors considered in this study.
Optimisation of parameters to maximise CBD or THC.
Experimental design and results of extraction (rows coloured by experiment: white indicates the initial factorial designed runs, light grey indicates mid-point runs, dark grey indicates repeat runs).
Carbon dioxide supercritical fluid extraction (CO2 SFE) is a clean and cost-effective method of extracting cannabinoids from cannabis. Using design of experiment methodologies an optimised protocol for extraction of medicinal cannabis bud material (population of mixed plants, combined THC:CBD approximately 1:1.5) was developed at a scale of one kg per extraction. Key variables investigated were CO2 flow rate, extraction time and extraction pressure. A total of 15 batches were analysed for process development using a two-level, full factorial design of experiments for three variable factors over eleven batches. The initial eleven batches demonstrated that CO2 flow rate has the most influence on the overall yield and recovery of the key cannabinoids, particularly CBD. The additional four batches were conducted as replicated runs at high flow rates to determine reproducibility. The highest extraction weight of 71 g (7.1%) was obtained under high flow rate (150 g/min), with long extraction time (600 min) at high pressure (320 bar). This method also gave the best recoveries of THC and CBD. This is the first study to report the repeated extraction of large amounts of cannabis (total 15 kg) to optimise the CO2 SFE extraction process for a pharmaceutical product.