A raw marijuana plant contains several important compounds, and carefully controlled processing can unlock others like THC. Many of these compounds change as they are heated. For example, cannabis contains THC in its acid form, THCa (non-psychoactive). When the plant material is exposed to heat, the THCa converts to THC.

A very specific heat and time ratio is critical, not only to convert THCa to THC, but also to prevent the THC from changing to a different compound. That’s why Apeks Supercritical has engineered thermally sensitive extraction systems using lower, plant-friendly temperatures for cold separation processing. Cold separation protects plant oils by never exposing them to temperature higher than the extraction temperatures, thereby protecting the volatile oils and terpenes, as well as retaining more THCa. Depending on the end product, processors may use the oils containing THCa (which offers its own therapeutic benefits) or convert it to THC.

To learn more about cold separation, watch this short video:


As described above, the conversion of THCa to THC requires heat. This is a chemical process called decarboxylation. The best way to get the highest yield when extracting cannabis is to decarboxylate it first. Typically, processors use ovens for this task. Once decarboxylated and dried, the material is ground up into a coffee-ground consistency. Watch a video of this process here:

The ground-up material is loaded into the machine and the processor/machine operator starts the extraction run. Unlike a subcritical extraction (low pressure, low temperature), a supercritical extraction (high pressure, high temperature) extracts everything from the plant, including some undesirable elements like fats, waxes, and lipids. These need to be removed via a process called winterization so that only pure oil remains.


The extract containing fats and waxes (a sludgy crude oil that looks like runny peanut butter) is mixed with 200-proof alcohol, and put in an industrial freezer overnight. The next day, the mixture is filtered through a funnel, trapping the undesirable elements onto filter paper. The mixture can be run through the filter several times. The wax-free oil then requires step two: removing the alcohol. This is done by gently warming the oil extract using a rotary evaporating machine. Alcohol’s boiling point is different from the oil’s, so it simply evaporates out of the oil. The alcohol is recovered and can be reused in the future. Once the oil is free of alcohol and plant wax, it can be further refined to separate individual compounds like THC using short path or fractional distillation.

All Apeks customers are eligible for a free winterization class! Watch a video of the class here:


Separating the individual compounds of the cannabis oil extract is a labor intensive and specialized process known as short path distillation, or fractional distillation. Each compound of the cannabis oil boils at a different temperature, so when the oil is heated, the compounds are siphoned off as they reach their particular boiling point. The whole process requires specialized equipment and takes some time, so is not for the faint of heart! Distilling the individual compounds creates “isolates” – oil containing one compound for medicines targeting specific ailments. There is also a strong case for maintaining all of the compounds in the oil (see the entourage effect described below).

Read more about Short Path Distillation here.


The current thinking is that the oil is even more therapeutic when all the compounds are included; the whole plant has so many beneficial compounds, that together, they offer the greatest benefit.


With the proper equipment and training, processors can extract specific compounds like THC. Understanding boiling points of each compound is critical. The entire extraction process takes time, money, and dedication but is well worth it!  And with an Apeks Supercritical system utilizing cold separation to preserve the terpenes and other compounds, you can join other customers producing award-winning oils!

Download a price list!
Click here