There are many widely acceptable ways to extract cannabis oil. As cannabis products become more regulated and rigorous testing standards are required, the extraction process will become crucial to the purity of the final product. An informed consumer should understand the difference between the most commonly-used extraction processes: Petroleum-based solvents, Ethanol and supercritical CO2.
While no extraction method is perfect, it is important to extract in a way that is safe/non-toxic as well as effective in capturing all of the synergistic compounds found in the hemp plant. The more beneficial compounds (such as cannabinoids, terpenes, polyphenols and flavonoids) that can be extracted out of the plant, the better they work together to produce an overall better effect.
Petroleum-based Extraction Explained
Petroleum-based solvents, such as Butane and Propane, were among the first extraction methods used by farmers, cannabis growers and home-grown CBD enthusiasts. These solvents work well due to their non-polarity, meaning they allow for the extraction of all the desired compounds (such as cannabinoids and terpenes) from the plant material without also extracting undesirable compounds (such as chlorophyll and plant metabolites). The problem with this extraction process is that it involves high heat and high pressure, is highly combustible and highly toxic, ruling out being a viable option by many health and wellness companies.
While petroleum-based solvents have their purpose, in a commercial setting, typically a solvent-based approach or a super critical (CO2) extraction are performed for safety, feasibility and cost efficiencies.
CO2 Extraction Explained
CO2 (Carbon Dioxide), at normal temperature and pressure, behaves like a gas. When it is cooled and pressurized, it reaches a state that is somewhere between a gas and a liquid. This in-between phase is called a supercritical state. In this state, CO2 can be passed through plant matter as a gas. However, because it also has physical properties of a liquid, CO2 makes for an intriguing extraction method.
The supercritical CO2 pulls out essential trichomes, terpenes and/or waxes from the plant material. The remaining solution (of supercritical CO2 and plant compounds) is then passed through a separator, where it is broken down into its constituent parts.
CO2 extraction, while seemingly new to the cannabis industry, has been around for decades. This is the same process that decaffeinates coffee and tea as well as the extraction process used to make essential oils for perfumes.
CO2 Extraction Benefits
CO2 is a naturally occurring compound that humans produce
CO2 can change from a liquid state to a supercritical state without exceeding temperatures above 90 degrees Fahrenheit, meaning there is less risk of compromising the natural compounds found in cannabis
CO2 is much safer than the petroleum-based hydrocarbons such as butane or propane in terms of toxicity
CO2 extraction is recognized in the cannabis industry for having an incredibly low environmental impact. Compared to a butane/propane extraction, CO2 is promoted as one of the safest techniques. However, despite these positives, CO2 is not without its flaws.
Supercritical CO2 Cons
Supercritical CO2 has been recently marketed as the "cleaner" or "solvent free" option for extracting cannabis. The truth is that it can be used in a solvent-free manner and the cold temps do well in preserving the volatile compounds of the plant.
The problem lies in using CO2 for hemp. CO2 will pull through a good amount of wax and chlorophyll, particularly when using hemp biomass as the extraction feedstock. Most extractors utilizing CO2 to extract hemp must still use a process called winterization. Winterization is a post-extraction process in which a solvent, usually ethanol, methanol or isopropanol, is used to remove unwanted waxes. Most companies using CO2 extractions perform winterization and then remove the solvents through a process called distillation – which is typically performed at very high heat. In this common method the two benefits of CO2 are lost; a solvent is still employed ("solvent free" therefore is not accurate) and the hemp extract is subjected to high heat (the cold benefits of CO2 are lost).
Furthermore, (and more importantly if you are consuming hemp-derived products for therapeutic benefits), this lengthy purification process, which is required to remove the co-extracted constituents (waxes and plant fats) from the extract, can take away from the final cannabinoid and terpenoid profile. A study published by Planta Medica in March of 2018 found that CO2 extraction drastically changed the chemical composition of cannabis. Compared with the dried plant flower, CO2 extracts eliminated many of the subtle flavor and aroma molecules that provide nuance and subtlety to the experiential effects of different cultivars.
Ethanol Extraction Explained
Ethanol is simply, alcohol. It is made from plant fermentation and is a by-product of plants themselves. In an ethanol extraction, organic food-grade ethanol is passed through hemp flower and brought to a very low boil. During this low boil, the hemp flower is gently cradled as it mixes with the ethanol creating natural friction, producing a vapor that is full of beneficial compounds. The ethanol can be recirculated through the plant matter multiple times, allowing for maximum extraction.
Alcohols are polar in nature, allowing ethanol to form bonds with both water-soluble and fat-soluble plant compounds. This quality makes the solvent a viable option for those seeking a full-spectrum extract. Unlike other solvents, such as CO2, ethanol is not as selective about what it pulls away from plant material, therefore it is able to harness all of the beneficial terpenes and phytochemicals, which other extraction methods may leave behind. Also, a sophisticated ethanol extraction process can effectively remove unwanted materials such as plant waxes and chlorophyll efficiently without the heat exposure that is used in other extraction methods.
Ethanol has been referred to as "the best of both worlds". This extraction method is recognized for having the efficiency of a butane extraction while maintaining the safety of CO2. The FDA classifies ethanol as safe for human consumption and therefore it is commonly used as a food preservative and food additive.
Ethanol Extraction Benefits
Ethanol is considered one of the safest solvents for consumer goods with organic and non-GMO feedstock options widely available.
Ethanol easily evaporates leaving no trace of solvent in the finished product
Ethanol is all-natural and made from plants
Ethanol is the only solvent that maintains the original chemical ratios contained in the plant. Ethanol dissolves both water and oil soluble chemicals while CO2 can only dissolve the oil-soluble chemicals.
Why Does Ananda Hemp Choose Ethanol Over CO2?
At Ananda Hemp, we have heavily researched and explored the available extraction methods, including supercritical CO2, since our inception. However, we are not convinced it is the lean, clean, green method that it is often touted to be in the hemp industry. High heats and the use of solvent are typically still necessary, and therefore, ethanol is the safer, more effective option for us.
In solely using an ethanol extraction, we do not have the issues of the built up chlorophyll and wax and we've found that ethanol alone pulls a broader spectrum of cannabinoids, terpenes and other beneficial properties (such as polyphenols and flavonoids) that you just aren't able to get with CO2.
There is a lot of misinformation out there but the proof is really in the products. When people take our products, there is no doubt they feel something different and we believe it's due to the method of extraction that pulls through more beneficial properties from the plant that CO2 may leave behind.
How Do We Make Sure Our Products Are Clean and Solvent-free?
We employ distillation techniques to remove the solvent from the extract. Our testing protocols test down to 1 part per million (1 ppm) in which no ethanol is found in our extracts.
We strive to keep our products as natural and as close to the hemp plant as possible. Ethanol is well-known in the herbalism world to be the most natural and efficient solvent to get the most beneficial compounds from the plants. These methods have been employed for hundreds, if not thousands of years which is why most of the larger herbal companies are still using ethanol extraction over CO2.
The cannabis industry will continue to emerge with new technologies, making consumption more efficient, effective and more accessible. However, this doesn't always equate to a better solution for extraction. We have found what works best for us in order to provide our customers with the healthiest products that have true therapeutic potential.