Marijuana extraction is an increasingly popular method today’s consumers are flocking to, but its roots go back thousands of years – as far back as the production of “charas” or resin in the Indian Neolithic period.
Today, cannabis oil extraction has gotten decidedly more sophisticated, involving chemical-based solvents like butane or ethanol, or solventless extraction processes that utilize nothing but plant material and natural elements to create the purest form of concentrate yet.
Depending on your needs as a consumer, there’s an extraction process that works for everyone, but it’s important to educate yourself on the different types of extraction methods and how they come about before making a decision on which method to pursue.
Solvent vs Solventless Extraction
When it comes to the varieties of cannabis extraction, it all comes down to solvents: a.k.a., a substance that dissolves the material within to create a solution. In this case, that solution is quality cannabis oil.
But while many extractors utilize chemical solvents to extract cannabinoids and terpenes, others believe the use of solvents can be toxic for consumers, and that’s where solventless and solvent-free methods come into play.
Solventless THC extraction approaches cannabis flower without the use of any chemicals, instead opting for natural, mechanical processes for extracting cannabinoids. This version of trichome separation can look like dry sifting flower through fine screens and utilizing heating and pressure, or using a rosin press (or a hair straightener, if you’re in a bind) or ice water to separate the trichomes from the plant matter.
Solvent-free extraction describes products that meet a particular region’s regulation requirements for residual solvents. But although the name implies these products don’t contain any solvents, that isn’t necessarily the case. Some regions will allow up to 5,000 parts per million for butane in cannabis oil, and because of this, conscious consumers will go for solventless products to ensure there is absolutely no risk of residual solvents showing up in their concentrates.
Below are some of the most popular methods of extraction for the cannabis plant, from the utilization of chemical solvents to solventless and solvent-free processes.
Supercritical CO2
This extraction method utilizes CO2 oil as the solvent for extracting major cannabinoids like THC and CBD. It’s considered one of the most non-toxic and environmentally-friendly solvent extraction methods on the market, promising to leave no traces of toxins behind.
Supercritical CO2 extraction isn’t just utilized in the cannabis industry: it’s a popular method of development used by the beer, coffee, fruit extract, and tea industries as well. With this method, supercritical CO2 is heated and passed through the cannabis buds via a separator, which helps remove the CO2 gas from the trichomes and terpenes.
Benefits
Supercritical CO2 extraction is often used to manufacture waxes and oils. As we mentioned earlier, it’s touted for its health benefits, as it seems to be the healthiest means of solvent-based extraction on the market.
Drawbacks
However, the biggest drawback of this method is its cost. It’s notably higher than other solvent-based methods, like alcohol or ethanol, but it also tends to result in higher yields of product, a longer shelf life, and less valuable plant material is lost in the process.
Ultimately, it all depends on the extractor’s long-term plans for supercritical CO2 extraction. If you’re looking for quick results at a cheap cost, this won’t be the best method for you. But if you have a little more time and are looking for consistently positive, high-yield results, you might want to look into this process.
Ethanol Extraction
Alcohol or ethanol extraction is one of the most common solvent-based processes for extractors, and one of the oldest methods on the market. A food-grade solvent that is utilized across a variety of industries beyond cannabis, ethanol is highly efficient at separating terpenes and cannabinoids from the plant at incredibly large volumes.
Although it may sound scary (and even dangerous) to mix cannabis with alcohol, it’s actually a quite natural process. Ethanol is a grain alcohol that is created from fermenting plant sugars, usually from corn.
It’s also a rather flexible option for extractors to utilize, as ethanol extraction can occur under a wide range of hot or cold temperatures, depending on your desired outcome. Most extractors use chilled or room temperature ethanol, immersing the plant with the chemical compound to dissolve the terpenes and cannabinoids.
Once the dissolution process is complete, extractors will remove the ethanol using a variety of evaporator systems, ensuring there are no traces of toxicity in the final product. Ethanol-based extraction is commonly utilized for products like cannabis oils and tinctures.
Benefits
The main benefit of the ethanol extraction process is the evaporation step, which is highly effective at removing unwanted compounds from the plant material and ultimately boosting the product’s purity.
When executed correctly and carefully, this process can result in some of the purest solvent-based products on the market.
Drawbacks
Although ethanol-based extraction can be great for product purity, it’s a little too easy to mess this step up, which can be disastrous for the product outcome.
Ethanol is a polar solvent, which means it has a pretty high propensity to mix with water, which can result in the dissolution of water-soluble compounds like chlorophyll. This can have a really negative effect on the product’s final result, messing with the flavor and aroma and rendering it pretty undesirable for consumers.
Hydrocarbon – Butane (BHO) and propane
Butane was used as the extraction solvent to create the first modern cannabis concentrate, resulting in butane hash oil (BHO). Also known as hydrocarbon extraction, this process is also utilized by the food processing industry.
In cannabis, BHO extraction can create a wide variety of cannabis concentrates, like topicals, vape oils, oils for edibles, shatter, crumble, and more. While most extractors will opt for butane over propane, some choose to do a blend of butane and propane (usually about 70:30) in order to optimize terpene preservation.
Benefits
One of the major benefits of the hydrocarbon extraction process is its temperature. Butane and propane both have a pretty low boiling point, which really helps with terpene and cannabinoid preservation and can result in more of a full-spectrum range for products than other methods allow for.
This method is also significantly faster than other methods, like supercritical CO2. And while supercritical CO2 extraction tends to produce a higher yield than ethanol extraction, BHO has them both beat. Because of this, products manufactured via this method tend to carry more therapeutic compounds for consumers and medical patients.
Drawbacks
Like any other method, BHO extraction comes with its fair share of risks – especially if you don’t know what you’re doing as an extractor. Amateur attempts that fail to provide enough ventilation can lead to explosions, as the solvents are flammable.
Commercial settings will come equipped with ventilation and gas detection systems to combat this, but if you’re attempting to do BHO extraction at home or in another unauthorized setting…maybe just don’t.
Water or Dry Ice
Water or dry ice extraction is a popular solventless process, utilizing nothing more than the plant, the elements, and agitation to reap successful results.
Ice water extraction involves submerging the cannabis plant in a mixture of water and ice in a series of mesh bags or containers. You’ll then agitate the mixture, allowing the cold water the break down the trichomes, which then fall to the bottom of the bag or container to be collected and preserved.
This method is highly effective and preservative, often resulting in concentrates that have anywhere between 50-70 percent THC. Popular products created from this process include bubble hash, ice hash, and water hash.
Benefits
Solventless extraction methods come with a wide variety of benefits, and water or dry ice extraction is no exception. This method promises the purest and most potent form of concentrate yet, as long as you have the right tools for the process.
It’s also great for capturing the flavor and aroma of the plant, which is important for consumer appeal. Ice water extraction in particular is also very preservative, resulting in higher yields and less waste.
Drawbacks
The main drawbacks here are the risk of contamination. If your flower isn’t 100 percent frozen before you begin the process, it can break apart more than it should, resulting in a contaminated and compromised product.
Heat and Pressure
Finally, a popular solventless method, particularly to create rosin, involves the use of heat and high pressure. Similar to how olive oil is made, this process breaks down the plant’s cells and releases its oils for consumption.
Benefits
Rosin pressing is one of the simplest methods on the market, especially when compared to solvent-based strategies. It comes with no risk of explosion and can result in some of the highest-quality concentrates on the market.
Drawbacks
If you want to ensure you’re getting the best bang for your buck, you’ll need to invest in a press with temperature-controlled settings, which can be somewhat costly depending on your budget.