Since the passage of the 2018 Farm Bill and the legalization of industrial hemp in the United States, the number...Read more
You know the saying, “Money doesn’t grow on trees”? Well, neither does CBD—even though it might seem that way considering how easily you can find CBD products these days. But in reality, there’s multiple steps in the process before you can consume it.
In earlier posts on our blog, we’ve written about how to grow quality hemp and what the actual farming process is like. We also did a general rundown of the production steps between hemp seed and store product. In that post, we briefly described the main types of extraction, but today we’re going to go a bit more in depth on each.
What is extraction?
First of all, what does extraction even mean? In general terms, extraction refers to the removal of something. Scientifically, it typically refers to the removal of one compound or substance from a larger compound or mixture, and in the case of CBD, it means isolating the cannabidiol compound, and sometimes related compounds and terpenes, from the hemp flower itself.
How is it done?
There are many different types of extraction, and they range from more DIY methods that you can do on your own with the right materials to very high-caliber, expensive methods only done in well-outfitted facilities. The four main types of extraction in the industry today are CO2, alcohol solvent, dry ice and olive oil.
CO2 extraction, or sometimes called supercritical CO2 extraction, is perhaps now the most popular type of CBD extraction among the broader public, in part because it’s also the safest. Supercritical CO2 is carbon dioxide in almost-liquid form—it’s not a gas at this point, but not quite a liquid either. (Yes, that’s a thing!) When in supercritical form, CO2 acts as a great solvent, easily passing through porous substances and dissolving necessary components.
How it works: Harvested hemp plants are ground up and placed into an extraction chamber. In a separate compression chamber, CO2 is put through low temperatures and very high pressure to turn it from a gas into its near-liquid state. Now as supercritical CO2, the carbon dioxide is released into the extraction chamber, where it passes through the ground plants, dissolving the unnecessary compounds and extracting the cannabinoid compounds as an oil. Then, the combined product moves to a chamber with pressure low enough to cause the separation of the CO2 from the plant oil extract.
- CO2 evaporates very quickly, so there is no leftover chemical residue or waste like there tends to be with other solvents. Therefore, it produces the cleanest, purest, and by default, safest extract.
- Because the machines are so exact and can be refined, leaving no margin for error, this extraction process is hyper-efficient and yields very precise, high-quality CBD.
- As you might expect, the machinery for this method is quite expensive, with a baseline cost of around $40,000.
- This type of extraction is complicated, and can only be done safely by experienced chemists and professionals. Definitely not DIY.
Alcohol and Hydrocarbon Solvent Extraction
What some might think of as the “OG” extraction method, alcohol/solvent extraction was made famous by one of the modern cannabis industry’s grandfathers (if we can call him that), Rick Simpson, who created his own concentrated cannabis oil to help treat his skin cancer and then started distributing it to others. It involves soaking the plant grounds in the solvent and adding heat . . . without any fancy compression or extraction chambers.
How it works: Hemp grounds are placed into a solvent, whether a natural alcohol solvent like ethanol (which has the “Generally Regarded as Safe,” or GRAS, label by the FDA) or a more traditional hydrocarbon solvent like butane, propane or isopropyl alcohol. The solvents, which have been used for years and years in traditional medicine to separate out chemical compounds, naturally strip the plant grounds of cannabinoid compounds and dissolves them, creating an extract oil-and-solvent mixture. Then, with the application of heat, the solvent evaporates, leaving only the desired oil extract.
- It’s far cheaper than CO2 extraction, especially when you’re talking about mass production, and requires much less sophisticated equipment. A definite DIY option (à la Rick Simpson).
- Faster than most methods.
- If working with ethanol, it can be really dangerous, as ethanol is highly flammable.
- If overheated, alcohol solvents can alter and weaken the structure and potency of the cannabinoid compounds.
- There is a chance of contaminant residue and resin to be left over after evaporation.
Typically done with olive oil, this extraction method is very affordable and consumption-safe but does not lead to high-concentration extracts.
How it works: First, the plant material is heated to induce carboxylation, or the activation of the carboxyl chemicals (a.k.a. cannabinoids!) in the plant. The material is then placed into olive oil, coconut oil or hemp oil and heated for longer, allowing the oil to absorb the cannabinoids from the plant material.
- This method is very easy and DIY-friendly. Does not require complicated equipment.
- Inexpensive, gentle and safe—no need for concerns over potential chemical residue.
- The shelf life of oil-based extractions is quite short, and they must be stored in specific environments.
- While it’s easy, this method is very time-consuming, and the actual yield and potency of CBD is very low.
Dry Ice Extraction
Another method for the personal production if you have the right equipment, dry ice extraction is fairly straightforward and does produce a pure CBD concentrate, although it’s not recommended or common for industrial production. The following equipment is necessary: mesh bags, rubber gloves, goggles and 2 pounds of dry ice.
How it works: The plant grounds are mixed with dry ice, which freezes the grounds and dissolves the plant product into a powder substance. The ice-powder mixture is then sifted through a mesh bag multiple times to filter out the extract, which settles to the bottom of the melted ice. Draining the ice-now-water leaves the cannabinoid extract.
- With the appropriate equipment and attire, you can do it yourself.
- This method yields more CBD than oil extraction.
- It’s just as time-consuming as oil extraction and very labor-intensive.
- Dry ice can be dangerous to work with.
Which is best?
The answer to this question very much depends on what your needs are, what equipment you have, how much experience you have working with materials like these, and what yield you’re looking for. For high-yield and high-quality or industrial production, CO2 and alcohol/solvent extractions are going to be the best options. For easier, less expensive extractions, you’d be better off with an oil extraction, or potentially dry ice, if you have the means and experience to be confident doing so.