Extracting cannabinoids and other compounds from raw cannabis can be done using a range of techniques. The most popular techniques are extraction using CO2, ethanol or a hydrocarbon such as butane. The selection of one of these techniques is based on a range of factors such as the final application of the product (such as what form it will take and whether its for recreational or medicinal use). It is also important to know the amount of raw material to be processed.
This article will focus on the method of ethanol extraction which can be done in a range of methods such as warm, cold or room-temperature processing. Lots of ethanol extraction processes require the use of a rotary evaporator to remove the ethanol from the extract solution.
This article will examine the method of ethanol extraction for cannabis applications, particularly focusing on ethanol removal with the use of a rotary evaporator.
How Ethanol Extraction Methods are Used for Cannabis Applications
There are three main methods of ethanol extraction which are:
Cold Process – this is when the cannabis plant is soaked in ethanol which has been chilled, stopping undesirable compounds such as waxes and pigments from turning to solids, however, it also means the extraction of desired compounds is slower.
Room Temperature Process – similar to the cold process, room temperature ethanol extraction involves raw cannabis being soaked in ethanol at room temperature to pull out soluble compounds. The cannabis is then removed and the solvent is evaporated.
Hot Process – this process involves using hot ethanol to solubilize compounds and requires the use of specialist equipment. This ethanol removal method is difficult to scale up and can lead to undesirable compounds ending up in the solvent.
Ethanol removal is popular for several reasons. It can extract a large range of compounds from cannabis plants, as well as the process being refined to stop certain compounds from solubilizing. It can also be scaled so it’s suitable for processing extremely large volumes of cannabis.
A Brief Guide to Ethanol Removal
Step 1: the plant is soaked in ethanol, causing certain compounds inside the plant to solubilize with the specific compounds extracted being dependent on the temperature of the ethanol and the makeup of the plant.
Step 2: After a sufficient amount of time the plant is removed from the mixture.
Step 3: The next step is the winterization process, which involves more ethanol followed by rapid cooling to remove lipids.
Step 4: the solvent must be removed for the solution, typically using a rotary evaporator.
Step 5: High purity cannabis oil remains, often with some residual solvent. This is removed by drying the oil in a vacuum oven.
Rotary Evaporators for Ethanol Removal
Rotary evaporators are extremely efficient in the removal of volatile solvents from non-volatile samples. Rotovaps decrease the solvent’s boiling point, minimizing exposure to heat, which is particularly important for temperature-sensitive compounds. Rotovaps are also environmentally friendly and have excellent repeatability.