Small Batch Ethanol Extraction of Cannabis
This method specifically retains more terpenes than most processes posted on the internet or in books. I wanted a nice clean extraction with no grit and the grade is edible so it doesn’t have to be as pure as it would for smoking or vaping.
Extracting cannabinoids using ethanol is a fairly simple process.
The following steps list, in detail, how to accomplish this as cleanly and efficiently as possible for small batch cannabis extractions. Waste is minimal, ethanol usage is moderate and safety is very high.
List of Supplies
Grinding The Cannabis
Ethanol is expensive and the local store was out of dry ice, so the next best thing is an electric coffee grinder. We grind the cannabis so that the volume is reduced, cutting down on the amount of expensive ethanol that’s needed.
The cannabis is loaded into the hopper so it’s nearly 3/4ths full. The grinder is pulsed 3-4 times, just barely hitting the button quickly enough to get the blades spinning. It helps with my grinder to shake it while bumping the grind button briefly. All we need is for the cannabis to be broken up in to farily even and tiny pieces, it does not need to be turned to complete dust.
Each batch is dumped into the stainless steel bowl for holding until the actual extraction takes place. Remember to keep everything clean and to work in a clean area. It took months to make this clean cannabis, let’s keep it that way while we work with it.
As you can see in the photo, the hopper is not quite full and the resulting cannabis is ground to an even, medium grain texture. The procedure is fairly quick and you’ll be surprised how much you can process in a very short time. The cannabis now takes up significantly less room and is ready for extraction.
Soaking With Ethanol
This is the point where we need to put the cannabis in to a stainless steel or glass container that can be covered and shaken. Load the ground cannabis into the container and pour in the ethanol until the cannabis is completely covered and then add a little bit more.
The amount of time the ethanol is touching cannabis is the main controller of quality at this point. A 30 second wash will produce a very high quality oil, though the quantity produced will be significantly less. Since this oil is destined for edibles the oil can contain higher amounts of plant waxes and chlorophyll. I usually wash the cannabis up to 5 minutes for edible extractions.
Filtering the Ethanol
Filtering the ethanol of all the cannabis material is as simple as pouring the mixture through a stack of unbleached coffee filters stacked in a funnel. It helps to have someone hold the funnel above the stainless steel or glass collection bowl. I have built myself a little stand that holds a funnel over a bowl. It worked well but needs to be shortened to reduce splashing.
Pre-Wet the coffee filters with ethanol before you start pouring your extract through them. This will ensure that the filters aren’t soaking up valuable cannabinoids with the initial ethanol.
Grinding the cannabis to a fine powder will actually clog the filters quickly and create enough fine particles that it will go right through coffee filters. Be sure to grind to a medium texture for best results.
Evaporating the Ethanol
Commercial Vs. Artisan
There are two main ways to remove the ethanol from the cannabis oils and those are quickly and slowly. The quick and commercial way is to simply raise the temperature of the alcohol to the boiling point and hold it there until the alcohol is completely boiled off. The second, artisan, way is to evaporate the alcohol at high speed, yet never boil it. The difference in the end product is noticeable as there are significantly more terpenes retained when the alcohol is evaporated slowly.
The commercial way is mainly used for reasons of speed, the alcohol is gone quicker when you boil it. This actually reduces the overall potency because there are terpenes being lost. The terpenes contribute to the way the cannabis effects people, so losing terpenes means the end product will be a ‘flatter’ experience, with less efficacy. Commercial oil is mainly the more robust cannabinoid oils, devoid of almost all terpenes.
The artisan way is used to preserve as many terpenes as possible, this is to retain as much effect and efficacy as possible. When comparing mg’s to mg’s, the more terpenes in a mg of oil, the stronger it’s going to affect the body and mind. This is why artisan canna-pills are as different as the strains they’re made from and commercial canna-pills all seem to be the same.
When your filtration methods are not lab quality, such as the stack of coffee filters I used, there will be some fine particles that get through. There is a simple method I borrowed from the beer brewing industry that will get rid of it easily.
Stir the ethanol in one direction only for 15-20 seconds and watch what happens. As the ethanol circulates, you’ll see all of the fine particles of sediment move to the center of the pan. (This does work best in a round pan, yes.)
This pile of sediment that collects in the middle is called the ‘trub’ in beer brewing. I simply grab a glass eyedropper and use it to suck up the sediment.
This process should only be necessary once or twice to get particles out that went through your filter. As you heat the ethanol the waxes will begin to drop out of suspension. There is a process called winterization that will remove these waxes, I generally leave them in as they come out during the decarboxylation process I use anyway.
The End Product
I stop evaporating the ethanol when there is still a little bit of ethanol left. The remaining amount I usually let evaporate slowly and naturally, again to retain as much terpene content as possible.
This produces as superior smelling, tasting and hitting oil than evaporating all the remaining ethanol under heat.
As you can see, the small tray of frosty trim produced several grams of high quality edibles oil. An extraction for smoking purposes would have made light yellow ethanol and yielded significantly less.
There are a number of things you could do with the oil from this point. You can winterize it to remove the waxes and mix it into topicals. Smoke it as is and relish in the feel of the plant waxes on your teeth as they keep the flavor in your mouth for hours. You can decarboxylate it and make canna-pills or tinctures from it.
Whatever your pleasure, small batch ethanol extractions are the best way to make high quality extractions from cannabis. Stay safe and…
Keep it Clean!