There is some debate, but in the case of Ethanol Extraction vs. CO2 Extraction there can be only one winner
By Anna Wilcox
Have you ever wondered how hemp oil is made? As it turns out, the quality of your hemp oil depends on the type of extraction process you use. The same hemp strain put through two different extraction processes can produce products that are distinct from one another, not only in appearance but in their chemical profile.
What Is Solvent Extraction?
Like all plants, cannabis produces an essential oil. This essential oil, however, cannot simply be melted off in a tea or washed away. After all, oil and water do not mix. A solvent is needed to separate the essential oil from plant matter. This solvent allows extractors to concentrate cannabis resin into a product of its own. This oil concentrate can be used by itself or infused into other goods, like foods and topicals.
Professional extractors use many different solvents to concentrate the essential oil of cannabis. Ethanol, butane, and propane are the most common solvents used by extractors. These solvents can be used to extract resin from psychoactive cannabis varieties and non-intoxicating hemp cultivars alike. Yet, not all solvents and extraction methods are created equal. Some, like ethanol and CO2, are safer for consumers and processors alike. However, even these two processes can produce dramatically different products.
What is Ethanol Extraction?
Extraction technician Jacob Ostler loading the filtered hemp extract solution into a rotary evaporator to remove the 99% isopropyl alcohol from the extract at CW Hemp. March 10, 2017, Boulder, Colorado. (Photo by Joe Amon/The Denver Post via Getty Images)
Ethanol is, simply put, alcohol. In ethanol extraction, the alcohol is used as a solvent. Unlike other solvents, like butane, ethanol is considered a safe and clean solvent that poses little risk of toxicity. Apart from solventless extractions, ethanol is considered one of the safest solvents to use in consumer goods. While all commercial extractions must undergo lab testing to ensure that unsafe levels of residual solvent are not present, ethanol easily evaporates and poses little risk to human health. Unless, of course, you drink it.
As a solvent, ethanol is highly efficient. Alcohols are polar in nature, allowing ethanol to form bonds with both water-soluble and fat-soluble plant compounds alike. This quality makes the solvent an excellent choice for those seeking a full-spectrum extract. Unlike other solvents, ethanol is not quite as picky about what it pulls away from plant material. As a result, simple at-home ethanol extractions tend to have a darker green color and more of a bitter taste. Though, professional equipment allows extractors to further purify their ethanol concentrates.
Ethanol is also often mixed with other solvents to produce extracts with specific properties. For example, the alcohol is frequently used at the end of a BHO or CO2 cycle to “winterize” the product by pulling out unwanted waxes. The end product will often be more translucent, with a light amber coloration.
How Does Ethanol Extraction Work?
Simple extractions using a high-proof grain alcohol can be made at home. Commercial extractors, however, prefer more technologically-advanced methods for extracting and purifying hemp resin. This technology passes ethanol through plant material and then recollects the ethanol at the end of the process. The ethanol can be recirculated around the plant material multiple times, allowing for the optimal extraction of essential oils. The end product is often syrupy in texture. Ethanol extractions produced with professional extraction machinery and properly processed will also be light to dark amber in coloration.
What is CO2 Extraction?
CO2 is carbon dioxide, which can be used in extraction processes when exposed to the correct temperature and pressure conditions. Like ethanol extraction, CO2 extraction is considered one of the safest forms of extraction possible. CO2 products pose little risk of toxicity to consumers, which is perhaps one of the reasons that vapor cartridges filled with CO2-extracted oils have become so wide-spread. Extractions made with CO2 tend to be light to dark amber in color and have a honey-like consistency.
Unlike ethanol, however, CO2 is very picky. While ethanol tends to easily dissolve both water-soluble and fat-soluble molecules, CO2 fails to extract much of the beneficial phytochemicals present in cannabis resin. This is why it believed many CO2 extractions use ethanol during the process—to capture these lost phytochemicals.
In fact, a study published by Planta Medica in early 2018 found that CO2 extraction drastically changed the chemical composition of cannabis strains. Compared with dried flower, CO2 extracts eliminated many of the subtle flavor and aroma molecules that provide nuance and subtlety to the experiential effects of different cultivars. CO2 extractions use ethanol during the process
When compared to the strain that went into the extraction process, the end result produced a significantly different product. Yet, for consumers hoping for a product that is as pure as possible, CO2 extraction is just a few steps down from an isolate. An isolate is purified CBD or THC on its own, separated from all other compounds.
How Does CO2 Extraction Work?
There is both art and science involved in making truly high-quality cannabis extractions. Many CO2 extractors use the supercritical CO2 method to safely extract cannabis resins. The CO2, which is normally a gas, is cooled and pressurized until it reaches a state that is somewhere between a gas and a liquid. This odd phase of matter is called a supercritical state. This in-between phase allows CO2 to be passed through plant material as a gas. However, because it also features many of the physical properties of a liquid, CO2 is often a successful extraction method.
The machinery used to process CO2 extractions often features three distinct chambers, one which pressurizes and chills CO2, one for the plant material, and one which Professional extractors use machinery that creates a closed-loop system, which allows the CO2 to be recaptured at the end of the process. Like ethanol, the ability to recapture and reuse CO2 makes this type of extraction fairly clean and efficient.
Ethanol Extraction vs. CO2 Extraction
The bottom line? “Ethanol Extraction is not only less of a drain on economic resources, but is safer when it comes to lab safety than combustible CO2,” explains AJ Yashim, a representative from Honeycomb Extracts. While no extraction method is perfect, ethanol is one of the best and safest for drawing out the subtle flavors, aromas, and synergistic compounds that are found in the cannabis plant. These compounds work with one another to amplify the beneficial compounds of hemp extracts. For this reason, ethanol extractions may be among the best for those hoping to use hemp oil for health and wellness purposes.
Even ethanol is not without its criticisms, however, Yet, what some consider a downfall to ethanol extraction is also the solvent’s primary benefit. Since ethanol is polar, it acts as a generalized solvent rather than a selective one. As a generalized solvent, ethanol is capable of extracting more phytochemicals than other solvents. This means that an ethanol-based extraction will have a greater nutrient-density when compared with other extractions.
As mentioned above, CO2’s pickier nature can miss out on some of the potentially nutritious phytochemicals during the extraction process. “The use of carbon dioxide results in a very limited extraction of the plant,” says Yashim. “Since the extracts of carbon dioxide are non-polar; carbon dioxide extracts are not water-soluble. This plays a vital role in bioavailability.” Many of the beneficial flavonoids and other phytochemicals in the cannabis plant are water-soluble. In order to effectively extract these micronutrients, a polar solvent is needed.
“Alcohol (ethanol) is a solvent that is made due to plant fermentation and is a by-product of plants themselves. It is a solvent made by the plants for the plants. Alcohol is also the only solvent that maintains the original chemical ratios contained in the plant. This is due to alcohol extracting both water soluble and oil soluble components. In other words, alcohol (ethanol) dissolves both water and oil soluble chemicals found in the plant while carbon dioxide can only dissolve the oil-soluble chemicals.”
None of this is to say that CO2 extraction is without its uses. Each method has their benefits and drawbacks. Using carbon dioxide can be an excellent way to extract nutrients from the cannabis plant and shouldn’t be overlooked. It’s simply that ethanol can be more efficient.
Professional extractors like those at Honeycomb Extracts have mastered the full-spectrum experience. Rather than adding additional aroma molecules or manipulating their product after extraction, Honeycomb Extracts starts with high-quality hemp from the very start. Organically grown with expert care, Honeycomb Extracts uses ethanol to showcase the integrity of excellent farming. Apart from MCT oil and a dash of stevia for sweetness, no additives or thinning agents are needed to improve their excellent ethanol extracts.