Cannabis extraction consulting

Ethanol vs. Hydrocarbon vs. Co2 vs. Solventless Extraction Processes: What’s the Best for My Laboratory?

Cannabis concentrates are the fastest growing segment in the market. There are many extraction techniques involved to create these products, some using organic solvents and other methods using pressure or even water. In commercial sized facilities, hydrocarbon, ethanol, Co2 and solventless are the most typical extraction processes utilized at scale.

What’s the difference between these extraction types, and how do you determine the best cannabis extraction method for your operation?

The cannabis plant produces trichomes, which contain a myriad of compounds that can be extracted and used in different ways. It’s important to point out that not all of these compounds are beneficial, and the type of solvent and extraction method chosen will have a significant effect on the final set of compounds contained within the cannabis extract.

In order to extract these compounds the cellular membrane must be dissolved or agitated, which releases the active compounds into the solvent. Non-polar solvents such as ethanol and hydrocarbons are particularly advantageous to this process, disrupting the lipid-bilayer which contains the desired compounds, but they are by no means the only way.

Any extraction method involving solvents should only be performed by qualified, experienced individuals using rated and inspected equipment. When considering the various methods of extraction, there are a number of factors to take into account such as cost, scale, safety, desired end products and legal availability in your particular region. Each method has different benefits, depending on what factors are important to the end goal of the operation. Let’s dive into these main commercial extraction methods.

Ethanol Extraction

Alcohol extraction is a widely available method of extraction that may have been used as early as 2000 BCE. For cannabis, it involves soaking the flowers in alcohol (preferably ethanol) to extract the trichomes into the solvent. The raw cannabis is then removed, the liquid is filtered, and the alcohol is distilled from the remaining oil. The advantage of ethanol extraction is that it doesn’t necessarily require high-end equipment and the process can be quite simple at a small scale. It also has the added benefit of the lowest price point, in terms of entry costs. Having said that, ethanol is also a perfect solvent for scaling cannabis extraction. Some of the largest extraction facilities we have seen in the Hemp space are using ethanol-based extraction to process 10,000 lbs+ in a single day.

The downside of ethanol extraction is that an operator is generally extremely limited in the final form factors of products that ethanol can produce.  This production method generally produces a crude oil that then goes into large scale distillation to remove the remaining undesirable compounds such as chlorophyll. Ethanol extraction generally yields tinctures and products that are infused with cannabis oil through distillation. A drawback here is that the distilled oil is devoid of terpenes and other phytochemicals that imbue cannabis oil with enhanced physical and psychoactive benefits.

Some other drawbacks of ethanol distillation is that it is a relatively inefficient process, since evaporation and recovery take large amounts of heating and cooling energy, physical space, and time. Over time ethanol purity will go down, meaning that it will require purification or replacement.

Hydrocarbon Extraction

Hydrocarbon extraction is one of the most popular methods of extraction, and for good reason. This form of cannabis extraction uses a hydrocarbon-based solvent (such as butane and propane) to extract compounds from the plant material. The polarity of the solvents is highly advantageous in that it allows the operator to be selective in what compounds are extracted, which allows the less desirable compounds such as chlorophyll and water-soluble compounds to be left behind.

New advances in hydrocarbon extraction technology have also been able to utilize practices similar to chromatography in separating the myriad of compounds available in the cannabis plant during the extraction process.  Since hydrocarbon solvents are extremely volatile, they easily evaporate making extractions relatively quick. Similarly, removing residual solvents from the oil is significantly easier. Hydrocarbon extraction also has the most options in terms of final form factors for consumer products, making everything from the highest quality dabable product to basic crude depending on operator experience, setup, SOP’s and equipment choice.

However, hydrocarbon extraction also has some major drawbacks which limits its viability for many operators. To begin, some local jurisdictions have deemed the process too dangerous and have outlawed the license types all together. Documented incidents involving licensed facilities showcase unfortunate situations where operators have gotten hurt — or worse. The volatile nature of hydrocarbon solvents requires significant facility infrastructure and engineering including rated extraction rooms, sophisticated gas detection systems, fire suppression, and certified and peer reviewed extraction equipment.  Most states will also require significant inspection and sign off from state and local authorities making the licensing aspect far more difficult, expensive, and time consuming.   To top it off, a simple operator error can pose a significant liability for any production facility and its personnel.

Building and operating these labs is capitally intensive but with the correct planning, implementation, and operation it can be worth it. Some of the most successful cannabis companies in the country that produce the highest quality oil products use hydrocarbon extraction, so there is a proven track record.

Co2 Extraction

Co2 extraction, also known as supercritical extraction, uses carbon dioxide “solvent” and requires the use of high-end, industrial-grade equipment for precise measurements, temperature control, and separation of the finished product. The supercritical Co2 extracts and isolates the terpenes and cannabinoids from the flower. The fluid is then separated from the flower.

Supercritical Co2 extraction was considered to be one of the best methods of extraction at scale in the early days of the recreational cannabis market. Most of the first concentrate products, including most pen cartridges at the time, were produced using Co2 oil. Co2 also enjoys a perception from some consumers that it is a “cleaner” technology than other solvent based extraction methods.

Recent improvements in Co2 technology also allow more specific ability to target and extract very specific cannabinoids such as cannabigerol (CBG), cannabichromene (CBC), cannabinol (CBN), and cannabicitran (CBT) (in addition to THC and CBD), and terpenes separately. These processes are still being tested at scale, and the lack of availability of appropriate biomass to extract these compounds effectively at an economy of scale poses a significant limitation.

Over time, Co2 has fallen into less favor due to operational and economic considerations.  As the market developed, other equipment and technologies advanced and consumer demand for different products evolved. One of the main drawbacks of CO2 extractions is that the process almost always produces a viscous oil that is typically delivered in an oral syringe or cartridge unless significant post processing expertise and equipment is also available. This presents a serious limitation to the products that can result from Co2 extraction – thus limiting the product SKUs that a facility can distribute to the market.

This method requires a major investment in expensive, high-end, often industrial-grade equipment. Co2 is inherently a poison at high concentrations, and rapid off-gassing from an equipment malfunction could cause suffocation for an operator.  Final form factors are limited and extractions take a very long time, making the production schedule inefficient.

Solventless Extraction

Solventless extraction encompasses many types of processing including ice water hash, dry sift hash, and Rosin. Whether separated mechanically, by temperature, or by pressure these types of concentrates have their roots founded in the traditional varieties of hashish.

Solventless is a small batch process, but when properly done can produce high end concentrates. Solventless hash is generally predicated by a very high-end input material because the ability to manipulate the process through extraction is limited. Equipment, specialized buildout, and  energy demands are generally minimal.

The drawbacks are that generally the ability to scale these production facilities are limited as the processes cannot be automated or be processed in large quantities- thus requiring significant physical labor. Desirable solventless concentrate can rarely be made from anything less than high end flower or whole plant fresh frozen material. There’s also an increased risk of having issues with water soluble compounds such as mold.

Which is the Best Extraction Method for Your Business?

Generally, cannabis brands find success when they are able to provide either a consistently high-end product or a variety of products to fill multiple price points on the shelf. Looking at your business model will indicate the direction and budget will indicate options.

If your desired array of products is focused on isolate or distillate based infused products such as tinctures, topicals, or edibles and you have high output facility demands, ethanol extraction with post refinement techniques such as distillation and crystallization will fit your needs.

If your desired array of products includes high terpene and high potency products at a large scale such as sugars, high terpene extracts, crystalline/terpene products, live resin, and cannabis derived vaporization cartridges and pods, hydrocarbon extraction is the best utilization.

At this point in the industry, the economic viability of Co2 is questionable and the idea that it is cleaner than any other method is a misnomer.  We believe that in general, Co2 is no longer an advantageous extraction method at scale mostly due to long extraction process times, potency, yields, and limited product form factors compared to hydrocarbon extraction.

Aside from desired product array, scale is the next criterion of analysis. For instance, a small-scale, high-quality grow could benefit from a solventless lab that would extract the high end flower paired with a simple ethanol extraction and distillation setup to process the trim. It would keep upfront costs down while providing a high end dabable product on the back end.

Medium sized grows could utilize a small hydrocarbon extraction lab that could take care of all processing for the facility, supplying high end live resin hydrocarbon hash while processing trim for crude.

Large facilities could utilize a large hydrocarbon setup for high end extraction at scale, pair an ethanol extractor for crude production for trim, and add a solventless setup for increase SKUs to market.

If you’re starting out in the cannabis extraction industry, having a team of seasoned experts to consult with can save you invaluable time and help you avoid common pitfalls, as well as help you determine what the best extraction method is for you and your business.

The UCG team has walked through every step of this process multiple times in multiple jurisdictions, and not only can we help you determine what the best cannabis extraction method is for your team, we can also help you with the appropriate facility specifications and buildout and train you in your chosen extraction method so that you are ready to hit the ground running – safely, successfully, and fully equipped for any issue that could arise.

Dylan Thiel

Dylan Thiel is the Chief Technical Officer of Union Cannabis Group. He also designed and now serves as the Lab Director in Washington’s premier cannabis extraction facility at Phat Panda (Grow Op Farms, LLC).