There are many steps to processing hemp into a consumer level product. One of the most critical, in terms of making a clean product, is winterization. No, this isn’t what your dad does to the lawn mower every fall. Winterization is a process that removes undesirable elements extracted from hemp, for example, fats, waxes and lipids. Without winterization these elements cause the final product to be cloudy, darker and have an unpleasant taste.
What steps come before winterization?
The winterization process starts with raw extract straight from our CO2 machine (see photo below). This crude oil contains all the essential parts of the hemp plant except for the actual plant material itself. CBD, minor cannabinoids, terpenes, fats, waxes, and lipids are all part of this viscous liquid. Crude oil extracted from a CO2 machine will have an attractive, light color to it, especially compared to alcohol extracted oil, which will have a dark, sludge-like appearance.
How does winterization work?
The crude oil is combined with 200 proof alcohol and stirred vigorously until completely mixed. The alcohol is used to thin the crude oil out, as the desirable parts of crude will go into solution with the alcohol while the undesirable parts will coagulate and freeze allowing them to be filtered out. The mixture is then placed in a deep freezer at below-zero temperatures. Once it has time to freeze it looks cloudy and is ready for filtration.
The next step is to place the mixture in vessels that use paper filters to remove the frozen fats, waxes and lipids. The actual CBD oil remains with the alcohol solution, and passes through the filter while the frozen undesirable parts are caught by it. The photo below shows what a filter will look like after having the solution pass through it:
When properly winterized, the filters will catch all of the frozen plant waxes from the oil, leaving them sitting on top. Once a pass is compete, the filters and waxes are discarded. The clean oil flows through the filter into a collection vessel where it is refrozen for more passes. We winterize multiple times just to make sure that our oil is 100% clean!
So wait, even though the oil is CO2 extracted, it will still contain alcohol?
Nope! The alcohol is just used to thin the CBD oil in order to properly filter it. Once it’s been filtered and the undesirable elements have been removed, it’s time to remove the alcohol. This is done with a piece of equipment called a rotary evaporator (rotovap).
This is CEO Craig Henderson, who started refining hemp from the garage of his home, using a rotovap in the early days of Extract Labs. This bad boy is a very efficient way to quickly distill the alcohol out of solution. The bulb spins in a hot water bath while the system is under vacuum, allowing the alcohol to evaporate out while leaving the winterized CBD oil spinning in the bulb. The alcohol vapors then travel up to the chiller coils where they condense into a liquid and drip down for collection. The alcohol is then recycled into our process. Once the rotovap is done with a work order, the spinning bulb will contain only clean winterized CBD oil. The winterized CBD is then ready to move on to the next phase of the process. From here, the winterized oil will be formulated into tinctures or it will move to our distillation department for further refinement.