Are all cannabis extracts created equal? Well… no.
Cannabis extracts can be created using several different solvents, such as carbon dioxide CO2, butane, or ethanol. Each one of these solvents is commonplace and effective for cannabis extraction, but some are intrinsically stronger solvents than others. Don’t let that mislead you – a stronger solvent isn’t always better. To understand why this is, let’s look at the typical compounds pulled during an extraction.
The obvious compounds extracted are cannabinoids like tetrahydrocannabinol (THC) and cannabidiol (CBD). Obtaining these is often the main reason for extracting in the first place, so you want to ensure you capture as much as possible. More recently, cannabis terpenes have been prioritized highly due to their role in the plant’s aromatic diversity and ‘personality’. These compounds are contained in the flower’s sticky resin glands called trichomes, the same glands that produce cannabinoids like THC and CBD. In fact, many consumers are now looking for a ‘full-spectrum’ extract – one with their favourite strain’s complete assemblage of terpenes and cannabinoids.
Still think your best choice is the strongest solvent? Keep reading.
Unfortunately, there are more compounds in cannabis than desirables like terpenes and cannabinoids. Chlorophyll, fats, and waxes are all co-extracted frequently, and are ultimately unwanted. These undesirable compounds require additional refinement processes if they are to be removed from the extracted crude oil. Often, this refinement entails significant temperature fluctuations to separate out the undesirables for removal. For example, mixing your oil with ethanol then placing it into the freezer (winterization) will separate out the fats and waxes for removal. The mixture then requires heat to remove the ethanol via evaporation.
Let’s say you used the strongest solvent possible for your cannabis extraction. Congratulations, you extracted (nearly) all the cannabinoids and terpenes! But don’t celebrate yet – unfortunately, you also pulled a ton of fat and wax. Here’s where things get tricky.
Terpenes can be destroyed completely if heated excessively. So, how do you evaporate out the ethanol added during winterization without heating and destroying your terpenes?
The answer is simple. Use CO2.
With a low-temperature and -pressure CO2 extraction tuned specifically for terpenes, you can extract the terpenes first and store them safely. This process is called a subcritical CO2 extraction, which uses liquid CO2 below its critical point. The liquid CO2 is pumped through the plant material, dissolving terpenes and some oils. Then the CO2 is decompressed and returns to its gaseous state, allowing the terpenes and oils to precipitate out for collection. After the terpenes are safe and sound, you can extract again, this time at a higher temperature and pressure. In fact, you can fine-tune the pressure and temperature to maximize your extraction efficiency by specifically targeting cannabinoids only and ignoring chlorophyll. Once your cannabinoids have been extracted, you can safely winterize them without worrying about damaging any terpenes. After refinement, the terpenes can be added back to the extract to produce a full-spectrum product.
The beauty of CO2 is its selectability.
An alcohol like ethanol is a powerful solvent – almost too powerful. It pulls all fats, waxes, chlorophyll, terpenes, and cannabinoids, giving you no choice as to what is extracted; it’s all or nothing. Similarly, butane (or other hydrocarbons like propane or hexane) is a strong solvent that extracts quickly and efficiently, but it too has little control over what can be targeted. What’s more, butane is highly combustible and difficult to scrub from the final product; your refined oil will contain trace amounts of butane, which may impact the flavour and aroma of the final concentrate.
Ultimately, alcohol- and hydrocarbon- based extractions offer little customization in the resulting extract, and the post-processing required to filter out undesirable compounds can severely diminish the final product’s quality.
With a CO2-based extraction system by Vitalis Extraction Technology, extractions can be customized with the fine-tuning of temperature and pressure to allow for precise extractions of nearly any desired compound. Businesses can create and market products based specifically around the molecular composition of the extract and its resulting effects and aromas. From ‘ultra-dank’ THC-based concentrates to therapeutic CBD-based medicines to valuable and aromatic terpenes, the options for cannabis-extract products are almost limitless with CO2.