There are many types of solvents that can be used to extract cannabis concentrates, but in general, people use:
Hydrocarbons (Butane, Propane, Hexane etc.)
Manufacturers that make butane hash oil or other hydrocarbon-based products should have special safety equipment and manufacturing equipment.
In other words, DON’T TRY THIS AT HOME.
In general, the process for creating hydrocarbon-based cannabis oil can be done with either an open loop or closed loop extraction equipment.
Open-loop systems are dangerous, even for experienced extractors. They are cheap, but they have resulted in many fatalities due to explosions.
Closed-loop systems are safer. They’re also much more expensive–much, much more expensive. They cost thousands of dollars. A certified machine can cost between $10,000 and $30,000 just for a small model.
Manufacturers must also have a blast-proof environment in which to do the extraction, along with special safety equipment for the people operating the equipment. Blast-proofing a room can cost around $100,000.
Most municipalities make it a serious felony to manufacture BHO or other concentrates involving volatile solvents in an unapproved area without a license. Penalties generally include severe fines in the 5 to 6 figure range and jail time for months or years.
CO2 (Supercritical CO2 Extraction)
Carbon dioxide is used for producing both extracts and concentrates. When used to make extracts, it’s called supercritical CO2 extraction. This process separates the different compounds from each other using solvents–most commonly CO2. The carbon dioxide is at such extreme pressure and temperature that it fluctuates between gaseous, liquid, and solid phases.
This state makes it possible to break down the cannabinoids and separate them.
CO2 extractors are becoming easier to buy on the market in legal states, and basic small-batch kits can be found for a few hundred to a few thousand dollars.
Again, this is something that requires special equipment and special training. CO2 extraction with a closed-loop system involves the use of high-pressure equipment and must be done correctly to be safe.
Some, but not all municipalities make it illegal to use CO2 as well as hydrocarbons.
There is a simple hack for home-based extraction, but it’s actually a dry ice method for making kief–a concentrate.
Those wishing to try supercritical CO2 extraction methods should check with their local government first (because chances are it’s illegal), and never try to use specialized equipment without proper training.
Serious injury or death can result from improper or careless use of extraction equipment.
People generally use alcohol as an extraction method to make super-concentrated Rick Simpson Oil.
Making your own cannabis extracts with alcohol is illegal in most places as well. This is because it’s a huge fire risk. Some people also attempt to use this method indoors which poses an explosion risk and risk of lung damage from vapors.
In short, lots of people use this method, and lots of people get injured doing it. Usually by setting themselves on fire.
This is because typical-strength alcohol doesn’t work. This method requires 151 proof alcohol, which is also illegal in many states.
Other solvents are used as well, but these are the ones most frequently preferred.