CBD can be sold in many forms, from pure CBD isolate, semi-purified distillate to full cannabinoid spectrum oils. We will discuss CBD distillate here, and try to provide clarity on what it is and how it’s made.
All compounds that have vapor pressure will distill. What is distillation? Distillation, in its simplest form, is simply heating a compound to its boiling point. This liberates the compound into the gaseous (vapor) phase. The vapor is passed through a tube that is chilled. This condenses the vapor back into a liquid (or solid if cold enough). In theory, this purifies the compound, especially if the compound has impurities that have much higher boiling points. In reality, unless highly specialized equipment is used, some impurities co-distill with the desired compound. So, while simple distillation will provide some purity upgrades, it is very hard to obtain 100% purity in the distillate.
Some compounds have a very high boiling point, and since materials decompose with heat, it is preferable to do the distillation at a lower temperature. Compounds boil at different temperatures depending on the pressure. The lower the pressure, the lower the boiling point. I’d have to get into some heavy thermodynamics to explain why, but the pressure/temperature couplet is universal. To distill high boiling point compounds, low, and sometimes extremely low pressures are needed. The absence of air defines a vacuum, and special vacuum pumps are used to pump out the air. Almost all of it.
It the case of CBD, the vacuum typically employed is ~10-4 of the normal atmospheric pressure. This allows the CBD to distill below 100 oC.
Why distill CBD? The main reason is to remove unwanted color from the crude CBD. While there can be some purification if done very carefully, basically the distillate is similar to the crude, except slightly higher in weight percent purity with much less color. There is a penalty though: you lose material in the distillation, perhaps as much as 30%.
So, CBD distillate is just a more aesthetically pleasing oil than crude. If done right, it can be nearly colorless and is suitable for vape pens, where color is important to the consumer. If you don’t care about color, or are not into vaping CBD, distillate is not for you. Buy a full spectrum product and get the benefits of the whole plant in your CBD.