Hello guys, first time poster...
Winterization is the process of removing plant fats, waxes and lipids, with the use of a secondary solvent, ideally with pure ethanol, or PGA, pure grain alcohol.
The bho is initially made as per usual, with a standard column extraction, most commonly done with the closed loop system, allowing the material to” soak” for an extended time frame, to expose the material to the solvent for a longer time, extracting all the goodies.
However with the extended exposure to the initial solvent (butane) happens to extract more waxes, fats and lipids and other impurities found in the plant matter.
The secondary solvent (ethanol, ever clear) is added to the extracted bho and dissolves into liquid form. The mistype is then placed in the freezer for a period of 48 hours, during which the said waxes, fats etc coagulate into a cloudy white clump in the jar.
After 48 hours the mixture is then poured through a coffee filter to collect the white clump, filtering takes some time, don't force filter by any means, just let it do it's thing.
Contingent upon the amount of oil, alcohol just needs to be evaporated away, preferably with heat, as the oleoresin will have a tendency to not reach the brittle state of shatter, unless the oil is exposed to temps in relation to their melting point.
What we have created is called an Absolute Amber, should be rock-hard glass with a prominent clarity, from removing plant waxes.
Some folks vac-purge their winterized bho, personally, unless the yield is huge, I see no practicality in vac purging.
Hope this helps, loving RIU so far..peace.