CBD is one of the most popular cannabinoids that come from cannabis. CBD continues to grow in popularity and has seen applications ranging from the food industry to the medical field. When it is extracted and isolated without any other cannabinoids, we call it isolate. CBD crystals are one form of CBD isolate available to users. CBD isolate is the purest form of cannabidiol, composed of at least 99% CBD. Through a unique extraction and purification process, manufacturers remove all other plant extracts from hemp-sourced CBD oil. What remains? An incredibly pure, white powder that is tasteless and odorless. Basically, these crystals are pure cannabidiol without other cannabinoids or other compounds. This means that the CBD crystals don’t have any traces of terpenes, flavonoids, THC, or the other compounds that are usually present in your typical full-spectrum CBD products.
Technically, CBD crystals are classified as pure CBD isolate. Cannabidiol crystals are available in the solid, diamond-like form. In order to make CBD crystals, you will need special equipments. Chromatography, which is a method of isolating and purifying cannabinoids, is often used in the cannabis industry to separate THC and CBD from already extracted cannabis. Crystallisation is a key step in CBD isolation. After chromatography is used to refine CBD to very high levels, removing THC, terpenes and other impurities, the CBD is further purified and collected in solid form by crystallising it from the extract. This is typically done with strong solvents which help remove the THC which stays liquid.
Most cannabis processors are not going to have access to industrial chromatography equipment to produce crystals, chromatography system is very expensive, you need very professional people to do the method development and run the system.
Without chromatography equipment, we can still make the CBD crystals, we can jump over the chromatography isolation step, just do the crystallization to get high purity CBD crystals. Turns out this is cost-effective method, widely used in making CBD crystals. Here we will introduce how to do it!
Quality CBD crystals begin with Quality CBD distillate. Always remember this. The starting material should be extracted CBD oil that has been decarbed, winterized and distilled. The CBD oil may need to go through several distillation passes before it’s considered pure enough to crystalize as a CBD isolate. It should be a very light yellow or completely clear in color once enough of the impurities are removed. CBD distillate should be clear. Cloudiness means there are contaminants like water, waxes and fats. If the oil is cloudy try winterizing again until the oil becomes clear.
A glass nutsche filter vessel with stirring will be used to dissolve and crystallize the CBD. A heating/cooling bath is connected to the vessel jacket and will be used to control the temperature of the vessel. You’ll also need pentane, it has a low boiling point, so it’s easy for it to overheat and cause issues during the crystallization process. . Be careful! This can be dangerous stuff.
Make sure the jacketed vessel’s vent/condenser is connected to an appropriate chiller for pentane vapors. The boiling point of pentane is 36C. Even at lower temperatures, pentane will release many vapors. BE CAREFUL AND TAKE ALL PROPER PRECAUTIONS! Make sure the vessel condenser is cooled to -20C. Use a three to one ratio of CBD oil to pentane and set the machine to stir this mixture(some oils require slightly more or less pentane) in the jacketed vessel. Turn on stirring and turn on the heating bath and set to 45C. Wait until the solution reaches 45C and all the oil has dissolved
Precipitation: Set the bath to 5C. Slow the stirring. As the solution cools it will become more viscous. Adjust the stirrer to keep the RPM above 120. CBD crystals will spontaneously form or crash out of the pentane solution. Keep reducing the temperature to at least -10 C. What temperatures you use and how they change over time can change the growth of the crystals.
Once precipitation stops, flush or physically remove The CBD crystals from the reactor. Vacuum filter the crystal/liquid slurry to remove the mother liquor from the CBD crystals. Rinse the crystals with ice-cold pentane to rinse impurities from the crystal surfaces. More rinses with pentane can improve poor color, but losses in total yield will occur. Keeping the CBD and materials cold during this step will help give you a better yield.
The mother liquor still contains dissolved CBD. This solution can be reprocessed! One caveat is that the mother liquor will accumulate THC over time. This sets a practical limitation to the number of crystallization.
Pentane and other volatiles can be very dangerous due to their low flash points. Don’t try this without consulting your safety officer and evaluating all of the possible safety concerns.