We asked our in-house R&D guru, Joel Hatfield to explain more about fractional distillation. If you know about winterization already, then skip to the part about fractional distillation below!
Starting with the initial extraction, the operator either processes it subcritically (low temperature, low pressure) or supercritically (high temperature, high pressure). If a subcritical run, the terpenes are retained. Sometimes customers set this extract aside, then process the material again, to extract the remainder of oil at supercritical parameters. This extract is then winterized to remove plant waxes, which refines the oil from the crude state. At that point, the first, subcritical extract is added back in, to add the terpenes.
The winterization process consists of 200 proof alcohol being added to the raw extract. It’s mixed well, then put in a deep freeze overnight. Then, it’s filtered through a funnel and flask, to remove the plant waxes. Usually a vacuum pump is used as well. The resulting oil doesn’t have any plant waxes but it’s still got the alcohol, so the mixture is heated in a rotary evaporator to remove the alcohol. If you need to purchase any winterization equipment, check out our website here.
Finally, we get to the fractional distillation stage! Cannabis has hundreds of compounds and fractional distillation is the process to extract them individually. This is not as terrifying as it sounds because each one has a different boiling point (see chart below), so the oil needs to be carefully heated, which will extract those specific compounds required.
Each compound has a different quality, used to treat different ailments, which is why fractional distillation is important.
If you have any questions for R&D guru Joel, please email us!
Click on the graphic below for a larger version.