Open blasting is an outdated method of cannabis extraction that uses a flammable solvent outside of a closed-loop system to “blast” trichomes off cannabis plant material. It is highly dangerous and does not meet standards for licensed cannabis extraction in any state because the flammable substances are not enclosed. It is not recommended.
“I heard a lab space burned down after open blasting some material.”
“A closed-loop system is way safer and more efficient than open blasting.”
What is open blasting?
Open blasting was an early method of cannabis extraction dating back to the 1990s in which a solvent like butane or propane was placed in a metal or glass container with cannabis material to “blast” off trichomes. These setups were mainly informal labs without trained professionals or safety protocols.
Open blasting, as its name implies, occurs in an open system and not in a closed-loop system as is required today by states with legal cannabis. The use of heat, pressure, and butane together creates a high risk of explosion, and the method requires higher amounts of butane than closed-loop systems, and the resulting product more extensive purging.
Today, no state allows for open blasting of any kind.
Safer extraction methods
In addition to being highly dangerous, open blasting is wasteful and outdated as new and improved methods have emerged. Closed-loop systems are now the norm, in which cannabis material and solvents are pressurized in a closed tube with a vacuum, which is far safer and easier to accomplish. Closed-loop systems also require less solvent and are easier to purge and refine products for commercial sale.