Botanical plants—long utilized for its medicinal and healing properties as well as for psychoactive and even spiritual purposes—is experiencing a rebirth in a big way. Around the globe, botanical plant users young and old are embracing this incredible plant, which has the capacity to prevent and even cure disease, correct neural and physical imbalances, and mitigate psychological disorders, including depression, anxiety, and schizophrenia. Long hailed as an effective cancer treatment and appetite stimulant, plant extractions are used the world over as a natural alternative to synthetic pharmaceuticals.
In recent years, extractions have taken center stage, alongside the advent of modern e-technologies. Botanical plant extracts, which preserve valuable compounds in plant matter, make use of solvents to create potent, stable extractions. Traditionally, butane has been used to create plant extractions, and supercritical C02 extraction represents a recent innovation in the realm of plant extractions.
Yet ethanol, a source for so many of today’s high-quality botanical extractions, is gaining traction as one of the most effective solvents on the market today.
Typical Botanical Extraction Methods
This brings us to the present day. There are now many levels and methods of plant extract refinement which will be briefly explained here. The categories are: steam distilling, cold ethanol extraction, supercritical CO2 fractionation, molecular distillation, and preparative chromatography.
Steam distilling is an ancient technique of extracting light terpenes or essential oils from plants. The technique involves passing steam through plant material and then liquefying the steam on a condenser. The essential oils are then floating on the surface of the recondensed water. These light oils constitute the fragrance and taste portion of the plant and are responsible for the “entourage effect” that in combination with the cannabinoids, distinguishes one strain from another. Recent developments in the science of terpenes and the positive effects on health and wellbeing underscores the importance of essential oils. The aromatherapy industry is obviously benefitting from these studies.
Extracting cannabis with cold ethanol, -20C or lower, has been discovered to pull cannabinoids and terpenes without extracting waxes and chlorophyll. This effectively eliminates the older refinement techniques of using carbon and winterizing. The only downside is yields tend to be lower so a warm ethanol extraction is often employed after the cold extraction to get remaining constituents. More about Cold Snap / Cold Ethanol
Supercritical CO2 fractionation
Conventional CO2 fractionation uses 2-4 separators to capture the extract after the co2 is passed through the the vessel filled with plant material. Pressure and temperature cascade downwards from the first to last separator resulting in different compounds of varying molecular weights dropping out in different vessels. This generally means that waxes fall out in the first separator. Heavy oils in the second separator, and lighter oils in any successive vessels. This technique works well for many botanicals but is generally unreliable with cannabis although an alternative method using this design can often result in nearly pure THCA, (95%) dropping out in the first separator which is certainly of value.
Another alternative method of extracting terpenes with supercritical CO2 is quite dependable. This method uses time instead of pressure and temperature to fractionate. Terpenes are almost instantly soluble in CO2 whereas cannabinoids other constituents take some time to begin dissolving in solution. This allows the machine operator to run the extractor for 15-45 minutes and collect the terpenes in relatively pure form before continuing the extraction to get the cannabinoids remaining constituents. More about Supercritical CO2 Extraction
This method is used to isolate terpenes and cannabinoids out of a first stage or raw, bulk extraction. There are a couple different designs for doing this, but they all involve using a combination of stirring, high heat, and deep vacuum to get the cannabinoid containing heavy oils to vaporize and re-liquefy on a warm condenser for capture in a distillate receiver. This method can yield oils with purity in the 95% range.
This the final frontier of botanical oil refinement.This method separates all the different components of an extract into their molecular parts and is referred to as “purification”. All the various terpenes and cannabinoids can be isolated and dropped into individual vessels. This allows for the creation of standardized formulations that can be made from any starting materials as long as that material contains some percentage of the desired ingredients.
The typical methodology here involves dissolving the extract in a combination of solvents and then pumping the solution through a column packed with an absorbent material. The various compounds lodge themselves in different spots in the column allowing for later recovery.
Preparative chromatography is widely used in the pharmaceutical industry for making pure drug compounds so it should be assumed that future medical cannabis products will employ this method. It’s also highly likely that some future recreational products will use preparative chromatography so they can offer the exact same product at any time or place.
Ethanol Extraction:the Logical Choice
Ethanol is the logical favorite. It’s effective, efficient, and safe—and that’s according to the FDA. Commonly used as an additive in everything from wine to whipped cream, ethanol is reliable, consistently producing potent extractions with minimal fuss.
Naturally, ethanol extraction comes with its downfalls—but the industry is working fast to address those drawbacks. Because ethanol is a polar solvent (unlike butane), it readily mixes with water, breaking down water-soluble molecules, like chlorophyll. Unfortunately, chlorophyll is also one of those “undesirables,” and ethanol extraction can make it difficult to pull the grassy-tasting compounds from the end product. A green, grassy extraction is unappealing to dabbers—those looking for a concentrated “hit” of a clean, pure extraction.
Fortunately, new innovations in chlorophyll detection and extraction mean that bitter, grassy extractions are becoming a thing of the past, and sooner than you might think. Multiple ethanol extractions, for example, can mitigate the presence of chlorophyll and other undesirables.
CO2 extractors typically come in fixed sizes, and capital costs are quite expensive. A 20liter extractor is among the most common, taking 8 pounds of plant material and allowing you to turn it into 400g of pure oil, usable for vaping or edibles. With ethanol extraction systems, we can customize to the exact weight or volume you want to make, allowing you to do small 1lb batches, to very large, 50lb or more extractions. These sanitary ethanol reactors come built with 316L stainless steel, recirculation system, plant material holders, and can have chilling jackets for dry ice or nitrogen supercold chilling.
High quality, effective extractions empower their users to feel healthier, stronger, and better nourished. The data is in, and it’s overwhelming: plant extraction and its incredible capabilities continue to exceed even our wildest expectations.