QWET OIL EXTRACTION FOR ORAL MEDS

January 20, 2012

Quick Wash Ethanol, also know as QWET is one of the techniques commonly employed to extract oil from cannabis.

Here is the skunk pharmer’s QWET formula to extract cannabis using a 3 minute quick wash.

As most of our extracted oil goes into oral meds, we also decarboxylate ours. This process is based on the 252F curve shown in the attached graph.

The first question is why use a quick wash technique to extract the resins, instead of long soaks to extract as much resin as possible, or just boiling the material in alcohol to get the greatest amount of extracted material?

The answer to that is that because alcohol is a highly polar solvent that is soluble in water, the latter two techniques also extract the water solubles like chlorophyll and plant alkaloids, as well as the plant waxes and vegetable oil.

Even quick wash does to a lesser degree, but the added steps that we include here minimize pickup even further and we take additional steps to remove the impurities that we do pick up.

The first wash will usually extract 75 to 80%, leaving the balance for the second. The second extraction will be more sedative and less heady. If you use a hand microscope, you can easily see when the trichome heads are gone and the stalks look like wet fur.

You can also use the material for other extraction methods after it has dried. I have subsequently used BHO after the first QWET wash that yielded 16% oil by weight, and got 5% more pristine oil, or about 21.6% total.

A cured material QWET absolute is one of the most aromatic and tasty of the extraction methods and consistently gets high raves from the volunteer test panels, as well as the patients and students. Both from an efficacy, as well as a flavor standpoint.

The first step in the process is to get as much water as possible out of the material.

A fresh material QWET is possible, but this procedure is specifically for material that has been cured to about 15% water content, which is typical of cured material. 15% is a lot of water and the alcohol already has 5% in it, so unless we reduce the water content even further, we will be extracting a lot of water solubles.

We dry our cured material even further by spreading it on a cookie sheet and baking it in a 200F oven until just frangible when rolled between the finger and thumb. We don't take all the water out, so that it is powder dry, as that makes it brittle and produces more fines to filter out.

If the material is prime bud, we break it up loosely by hand and extract from trim as is.

If it is trim or leaf, we scrub it through a pasta strainer by hand, using a leather gloved hand.

We never, ever, use a blender or coffee grinder to reduce material, because it produces a lot of ultra fine powder that makes subsequent filtration more difficult.

Next, while it is still warm, we seal the material in a jar, which we place in the freezer to tie up any remaining water as ice. We also put the 190 proof grain alcohol in the freezer.

When they have both stabilized at about -32C/0F, we pour the alcohol into the jar of plant material, so that it is at least an inch above the material, and shake it gently a few times to make sure everything is wet, before returning it to the freezer.

We remove and gently shake twice more until the material has soaked for 3 minutes, and then dump it through a wire strainer to drain quickly. We press on the plant material in the sieve, to force out remaining alcohol.

We set the material aside to dry for a second extraction and usually keep the two extractions separate, as they will have different properties.

We filter the extracted liquid using vacuum assist with a #1 lab filter, or just gravity and a simple coffee filter, depending on the quantity we are processing.

We place that filtered liquid in a still made from a stainless asparagus steamer pot, replete with an ice water condenser from a stainless mixing bowl with copper coils, to cook off and recover most of the ethanol. For small quantities, we just boil it off to atmosphere.

We don't fully reduce the solution in the still, because it makes subsequent processing difficult. What we do instead, is stop before the solution is fully reduced, and pour the remaining solution into either a Pyrex beaker, or a stainless bain marie container and set that container in an oil bath heated to 250F.

We set the container on three of four canning jar rings setting in the bottom of the pot, so as to keep the container suspended up off the bottom of the oil pot, so as to insure even heating without hot spots.

We never trust the numbers on the dial and use either a mercury lab thermometer, or a digital one to monitor oil bath temperatures and an infra red optical one to monitor the actual solution temperature.

Good temperature control is key to the process, and if you control the temperature of the oil bath, and watch what is happening in the solution itself, you never have to measure its temperature. The solution temperature will stay around 78C/173F at sea level until the alcohol is gone and then start to rise to oil bath temperature. From that point on, with the oil bath temperature constant, the process is controlled by visual observation.

That means the device that you use to control the oil temperature must have a narrow dead band, so that the temperature control is stable.

I paid about $60 for a Quisinart fondue pot that was designed to heat sensitive sauces like chocolate and has excellent control throughout its temperature range. I picked up a second used one at Goodwill for $15, so do scout about. There are also a couple of $30 Revels in our group that are slightly larger and work well, though they have a slightly larger dead band in the temperature control.

Some fry cookers may have sensitive enough controls, but many deep fryers designed to primarily run at 375F, lack control sensitivity and have large dead bands at 250F.

We either boil or distill off the alcohol until the liquid is reduced to a pool of oil, with no large solvent bubbles. I speed up that process by sticking three or four bamboo skewers into the bath to provide points of bubble nucleation. You can also use boiling chips, but they are hard to remove afterwards without losing some of the oil as well.

Caution: Beware of licking skewers dipped in QWET oil while processing, as it is not hard to overmedicate.

Besides solvent bubbles of mixed sizes, there will be some fine equally sized bubbles that persist after the solvent bubbles are gone. Some of those are the lighter turpenes being volatized, but primarily they are CO2 bubbles from decarboxylation. As you can see by the accompanying decarboxylation graph, compliments of Jump, maximum THC levels are achieved at about 70% decarboxylation, after which the levels fall off sharply as THC is converted to CBN faster than the remaining THCA is converted to THC.

That point is easily discernable by observation. If you are using a skewer to keep the bubbles broken loose from the bottom and corners of the pot, at about 70% decarboxylation, the bubbling rate will dramatically drop off to almost nothing. If we are making more sedative night time meds, we continue to cook the oil until all bubbles stop.

All of our containers are marked for tare, so at that point we remove the pot from the oil bath and wipe off the outside, before setting it on a scale and by subtracting the tare, and determining how much oil we have extracted. Once we know the extracted weight, we calculate and add the other ingredients to the desired potion. Once adding those ingredients, we place the cup back in the oil bath, and stir it until well mixed and before decanting into its final container using a funnel or glass syringe.

Since the added ingredients include things that lower the cannabis oils viscosity, very little is left as a film in that container.

If we plan to use the oil as is, without adding any other ingredients, we extract it from the container using the glass syringe, or a pipette, so as to not leave a streak of material in the vessel. After we have extracted all that I can using a syringe or pipette, we wash the container and pipette out with hot alcohol, and save the wash for the next run.

Nothing is wasted or left behind.

Below are pictures of the frozen plant material and alcohol prior to straining, as well as the pasta strainer sitting in a finer mesh French chinoise to rapidly drain before re-filtering to get out the fines.