Winterization of extracts made on Merlin400

When it comes to processing and using cannabis, cannabis users are very creative.
I guess by now someone, somewhere has tried and tested almost any idea concerning how to treat and use marijuana: Pressing, sifting, cooking, vaping, smoking, as an ointment, aphrodisiac, medicine, (re)creative agent, extracting with fat, alcohol, butane, Co2, cold distillation, quick wash, feco, rso, vacuum distillation, decarboxylation… and winterization. You name it, someone has been there.

Winterization is one of these ideas. It is a tried and tested way of cleaning your extract using frost to remove unwanted parts, typically fats, wax and lipids.
I wanted to test this method but using available equipment in my home, no special gear.
So after gathering some background knowledge, I started off, using whatever parts I had around.
I used an extract made on Merlin400, from CBD trim grown by Hempire gardens: High quality, cheap, and I know the taste, colour and viscosity I could expect.

I dissolved the extract in isopropanol (1 part extract to 10 parts IPA) and placed the IPA/extract mix in an upright bottle, in the freezer compartment of my refrigerator.

My freezer is cold, but not really cold. Maybe minus 15C, far from the minus 50-60C recommended for winterization, but as mentioned I wanted to see what is possible without special equipment.

After 24 hours, I got some flocculation – a white ’fog’ had separated from the rest, but was still evenly distributed in the liquid. After 48 hours, the white fog had formed a butter-ish layer on the bottom, ready to be separated from the top part.

The general advice at this step is to remove the precipitated white ´butter’ by filtering the mix in a Büchner funnel. But having no Büchner funnel and no proper filter, I used a syringe to carefully remove the clear top part of the mix, while leaving the white butter at the bottom.

Separating the two fractions

This way I ended up with two fractions. The top 80% of the mix was more transparent and had a brighter colour than the starting mix, while the bottom 20% was the opaque white layer of wax and fats.

With a higher, thinner glass I think I could have made a better separation, closer to 90/10% instead of the 80/20%. A colder freezer would also have given a better separation but using what I had available actually gave a decent result.

Left: the bottom 20% ‘butter’, Right: the 80% purified extract/IPA mix

I distilled the fractions one by one in my Merlin400. Out of the original 2 grams of extract, the purified fraction yielded 1,7 grams, while the cloudy butter fraction yielded 0,3 grams, close to the 80/20 balance of the two fractions.

And what a difference! The bottom 20% gave a solid, black extract with little to no smell at room temperature.
The top 80% gave an extract that was slightly more transparent and had a more brownish/golden colour than the starting material. It had a beautiful rich smell and was also much more fluid.
The surface was more shiny compared to the matte surface of the starting material.

The purified extract after winterization

I have no access to precise measuring equipment (yet…) but my gut feeling is that the winterization removed 20% of the weight, but removed a smaller fraction of the cannabinoids.

I loaded a vaporizer cartridge with the purified extract – the taste was remarkably better than what I know from vaping the ”normal’ Hempire CBD-trim extract. Usually, it has a nice taste with a sharp edge.
The winterized extract had all the nice taste, but much less of the sharp edge, and vaped smoothly, giving satisfying hits and nice ‘clouds’.
I have been looking for a ‘thinner’ for THC-rich extracts in vaporizer cartridges, and I don’t want to vape just anything, but… maybe purified CBD-rich extract could make a great thinning agent?

All in all, the winterization test was a success. I am looking forward to trying this on both CBG- and THC-rich extracts!