Quick Wash Isopropyl, also know as QWISO is one of the techniques that skunk pharm uses to extract oil from mixed leaf for topicals and sometimes buds or trim for vaporization. Here is our technique for producing a pristine oleoresin extraction.
We also decarboxylate our oil for topicals and based on the 122C/252F curve shown in the attached graph, courtesy of Jump.
Note that the boiling point of the terpene ß-caryophyllene is 119C/246.2F, so it is boiled off at that temperature, and its anti-inflammatory, cytoprotective (gastric mucosa), and anti-malarial properties are diminished or lost.
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 reflux 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, so that they are not left behind on the skin.
The first wash will usually extract 75 to 80%, leaving the balance for the second. If you use a hand microscope, you can easily see when the trichome heads are gone and the stalks look like wet fur.
A cured material QWISO absolute made from prime bud, is one of the most aromatic and tasty of the extraction and consistently gets high raves from the volunteer test panels, as well as the patients and students when vaporized. Both from an efficacy, as well as a flavor standpoint.
This process is for mixed leaf material however, which includes fan leaves, so it usually isn't all that tasty.
The first step in the process is to get as much water as possible out of the material. Typically material for smoking has been cured to about 15% water content. 15% is a lot of water and the alcohol already has 1% 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.
At this point, we have a choice of running the leaf whole, or reducing it in size to improve packing. Leaving it whole will produce a more pristine extraction, with the least amount of chlorophyll pickup, and we do it both ways.
When we make QWISO for vaporizing, or for a show and tell beauty contest, we always leave the leaves whole.
When reducing it in size, while it is still warm from the oven, we force the material through a pasta strainer.
In both cases, we seal the material in a jar while still warm and place in the freezer to tie up any remaining water as ice. We also put the 99% Isopropyl 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 for 20 seconds.
At the end of 20 seconds, we dump it through a wire strainer to drain quickly. I use a pasta strainer to catch the bulk of the material, followed by a fine mesh French Chinoise. This allows the material and the alcohol to separate fast.
We set the material aside to dry and refreeze for a second extraction.
Next we filter the alcohol, using either vacuum and a #1 lab filter, filter or a simple coffee filter, depending on the quantity we are processing.
After filtration, there are a couple of directions to go, depend on use. If it is to be used for vaporizing, we may place it on a large surface area dish, like a Pyrex pie plate, and just blow air over it. That reduces it fast, but is not a suitable technique in dusty areas. That can be improved somewhat by placing cheese cloth over the dish and blowing over the top of that.
When the alcohol is visually gone, place the dish on a 140F heat mat, or float it in a hot water dish, until the smell and taste of the Isopropyl is gone, usually around 30 minutes to an hour.
For our use in topical, we place the filtered liquid in a bain marie stainless vessel and place that into an oil bath heated to 121C/250F.
I throw four jar lids in the bottom of my electric fondue pot to suspend the container up off the bottom, to eliminate hot spots and never trust the numbers on the fondue pot dial. Instead, I use a good mercury lab, or a digital thermometer to set the dials. Good temperature control is key to the process.
That means the device that we use to control the oil temperature must have a narrow dead band, so that the temperature control is stable.
We 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. We scored a second one for $15 at Goodwill, so do shop about.
There are a couple of Revels in our group that are slightly larger and work well, plus cost only about $30, though they have a slightly larger dead band.
Some fry cookers 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 boil off the alcohol until the liquid is reduced to a pool of oil and all but minor bubbles cease rising at the edges and then pour in at least ten volumes of ethanol and wash out the whole pot by swirling it and washing off any resin stuck to the sides.
Using a funnel, we pour that liquid into a jar or bottle, seal it, and place that in the freezer. After about 48 hours at -18C/0F, the liquid will lose its clarity and become slightly cloudy, from marginally dissolved inactive ingredients like waxes and lipids flocculating out. There will also be precipitant on the bottom of the container. While this step isn't totally necessary, it makes a cleaner, more pristine oil.
Next, we carefully decant and filter that liquid one more time, leaving a bell clear extract, that is ready to reduce down a final time.
We pour it into a Pyrex beaker or a stainless bain marie container for return to the oil bath and since we have much less material, we use a smaller container to keep film losses low.
When the oil is completely bubble free, we remove it from the oil bath, wipe it off, and weigh it. As we know the tare weights of our containers, we subtract it from our total weight and add the rest of the required ingredients for the topical into the same container, based on the amount of cannabis oil present.
We then set the container back into the oil bath and stir until thoroughly mixed and then remove it from the container using a glass syringe, so as to not leave a streak of material in the vessel. Attached thumbnail(s)