Industrial hemp production is growing rapidly globally due to the explosive growth in CBD. Extracting THC, CBD, other cannabinoids, and terpenes from the hemp and cannabis plant is done using a variety of methods. The most common ethanol extraction methods are:
- CO2 Extractors – supercritical C02 extraction
- Butane Extractors – using butane as the solvent
- Rosin Press – squeezing the plant with hydraulic presses
- Ethanol Extraction – using ethanol as the solvent
- Solvent Extraction – other solvents
Why choose ethanol for botanical solvent extractions?
Pure Ethanol is food grade, GRAS, and readily available. Extractions using ethanol can be done in simple stainless steel tanks or more complex tank systems. This equipment is fairly inexpensive and simple compared to C02 and Butane extraction equipment. Ethanol is flammable and should be handled with care, and any rooms should be properly vented and all tankage/piping should be grounded per code. Ethanol extraction is a source for so many of today’s high-quality botanical extractions and is gaining traction as one of the most effective solvents on the market today.
Typical Botanical Extraction Methods
For so long, extractions were created with butane, which boils at a lower point than other common solvents, including alcohol. Because of butane’s non-polarity, extractions containing specific cannabinoids and terpenes are easier to produce, since specific compounds may be drawn from the plant matter without co-extracting chlorophyll and other “undesirables.” Yet butane is also famously flammable – think lighter fluid – and many explosions have occurred as a result of DIY butane extractions gone wrong.
Supercritical CO2 extraction, then, is perhaps more appealing than butane extraction simply because of its relative safety. With a minimal environmental footprint, many favor supercritical CO2 extraction. Although CO2 is often the most desired method for making vape oil and distillates, the equipment is quite expensive and does run under high pressures in the 1500-5000psi range.
Why Ethanol Extraction is the Logical Choice
Ethanol is a logical favorite.
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. Post process equipment including filtration and distillation can be used to remove and mitigate the chlorophyll and clean up the oil into a desirable distillate. After extraction, all the ethanol is reclaimed using rotovap (rotary evaporator) technology or high volume solvent recovery systems.
With ethanol extraction systems, we can customize to the exact weight or volume you want to make, allowing you to do small 1pound batches to very large 500lb 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. Some common ethanol extractor setups:
HEATED ETHANOL EXTRACTIONS
Applying heat can improve extraction yields and pull more material out of the base plant. Some extractors have chilled condensing coils at the top of the tank, and neat alcohol drips back down thru the plant. This is a very common method of making tinctures.
SUPERCHILLED EXTRACTION
Chilling the ethanol and plant at -40f range will provide a much cleaner extraction, by eliminating pulling a lot of chlorophyll out of the plant. Tanks can be chilled by dry ice, jacketed double wall tanks with chilled ethylene glycol, or with superchilled nitrogen or CO2 high-pressure coils. Jacketed tanks with a chiller are very common.
AGITATED EXTRACTION WITH SPINNING BASKET ON TOP ENTRY MIXER
Using a top entry mixer in your tank will provide turbulence and mass transfer, which can improve extraction yields by exposing more ethanol to the plant material and providing a mixing action. Adding a spinning basket that holds the plant material, or holds bubble bags with the plant, you can drain the tank and dewater (spin the basket and remove all the extract and ethanol from the plant) the plant to get most of the moisture out and avoid hand squeezing the plant. The spinning basket acts just like a washing machine during the final cycle to remove all the fluid.
RECIRCULATION EXTRACTION WITH PUMP
Recirculating the ethanol and extract with a pump can provide turbulence and mass transfer to improve extraction rates and yields. The pump can then be used to drain the tank at the end of the cycle.
Below is a chart showing the overview of extraction (shows CO2) thru final fill and packaging for vape cartridges. With Ethanol Extraction, labs can process small to very large volumes (typical for hemp processing for large-scale CBD production) and scaling up and down is consistent and repeatable other than variations in the incoming plant material.
