Most of us know the basics of how concentrates are made: Cannabis is soaked in a solvent, which dissolves the cannabinoids and terpenes; the solvent is then evaporated, and what’s left behind is a very concentrated form of the plant’s active ingredients.
Now that we’re all on the same page, let’s look a little deeper into the solvents most commonly used for making extracts. A solvent’s polarity refers to the electrical charge it carries. Polar solvents, such as water, have an electrical charge due to the arrangement of atoms in their molecules. Polarity is the reason that oil and water will not mix into a solution. When it comes to dissolving THC, it’s all about polarity—or, more specifically, non-polarity. Cannabinoids will dissolve into any non-polar solvent, and there are many of these to choose from.
Here are some of the most common non-polar solvents used in the hash-making industry:
This solvent is cheap and easy to obtain. It’s commonly used as a secondary solvent or wash in conjunction with some of the other solvents on this list. The yields from isopropanol hash are pretty low, but it’s very safe to work with.
Carbon dioxide is in the air we breathe, and it’s non-explosive. It will dissolve THC and other cannabinoids when in supercritical form (i.e., under so much pressure that the gas becomes a liquid). The downside is that the equipment needed to make CO2 supercritical is very expensive and takes some training to operate safely.
This is the most commonly used solvent for hash-making because it’s excellent at capturing cannabinoids and terpenes, and it’s also easily purged from the final product. It is non-toxic, cheap and fairly easy to obtain, but it has an extremely high risk of explosion. Amateur hash-makers should probably not cut their teeth making butane hash oil.
Propane is a very good solvent for making hash, since it does a great job of capturing terpenes. This solvent is almost always odorized, which allows you to smell it if it’s leaking from a storage container. However, if you’re making hash with propane, you’ll have to find a source that is not odorized.
Hexane is commonly used for making pharmaceuticals and food products. It has qualities similar to butane but is harder to get as well as more expensive. When working with hexane, you must take all of the same safety precautions as when working with butane. In gas form, it will easily ignite and explode.
Ether is the solvent of choice for most pharmaceutical production, since it evaporates at room temperature. The downside to this solvent is that it’s extremely dangerous to work with. Ether can auto-ignite at relatively low temperatures (i.e., start a fire without a spark). Even if you can get your hands on this stuff, it’s probably a bad idea to work with it unless you’re a professionally trained lab technician.
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