Because of their ability to create heated and pressurized environments with pinpoint accuracy, vacuum ovens have long been a staple in the medical, tech and aerospace industries to remove toxic chemicals from medicines, cure circuit boards and simulate the vacuum of space.
The cannabis industry quickly adopted the technology, which has become increasingly important as the industry has grown, evolving from an add-on to a necessity for butane/hydrocarbon extractors due to their ability to remove potentially harmful solvents from the extracted materials.
Due to their variable levels of controlled heat and pressure, vacuum ovens are now commonly used across the industry to do everything from curing and drying extracts to decarboxylation. Stand-alone units that look more like small cooking appliances than extraction equipment, vacuum ovens house a series of shelves where processors can spread out extract on thin sheets and essentially bake out unwanted residual materials from their extracts using a controlled, uniform temperature and vacuum pressure.
“Having a thinner, broader surface area is better because it creates less of a path for what we are trying to pull out of the material,” says Jackson Capedeville, the application specialist for Cascade Sciences. “If you are trying to pull a particular hydrocarbon or a butane molecule out from three, four inches of depth in a glass jar versus half an inch, spread thin, the ability to purge those solvents more efficiently increases quite a bit.”
Vacuum ovens can efficiently remove residual solvents from extracts to ensure they are within the state-mandated thresholds in order to be suitable to sell for consumption.
Each state has their own level of tolerance for various solvents. In Colorado, for example, butane and heptane are 5,000 parts per million, while benzene is just 2 PPM.
“Vacuum ovens are a must-have when using hydrocarbon extraction because they liberate the final bits of solvent out of the extracted material making the PPM at levels legal for sale,” Capdeville says.
The units also naturally assist in drying extract products. Capdeville says they also preserve the natural color and smell of plant extracts. In addition, he says that under low temperatures vacuum ovens can also keep extracts from melting or transitioning from their desired state.
Vacuum ovens do not need to be matched to a specific model of extraction equipment.