Vacuum drying has been around for a long time but has come in to the media spotlight as of late. Why? The legalization of marijuana. Cannabis extractors will use vacuum oven drying to extract pure THC while removing impurities. Cascade TEK has provided an infographic to depict the oven drying process.
The steps of vacuum oven drying are relatively simple. First, liquid moisture must be changed to a gaseous state. Second, the vacuum oven decreases pressure, which will drop the temperature required for liquids to vaporize. This step allows the third, moisture evaporates and dries the compound at a lower temperature.
As you may know, water boils at lower temperatures in higher elevations. For example, at sea level, water boils at 212 degrees Fahrenheit (100 degrees Celsius). If you were to visit Denver, that water boiling temperature decreases to 202.5 degrees F (94.7 Celsius). At Mount Everest, water boils at 154 degrees F (68 degrees Celsius).
Vacuum drying can be used for more things than just the removal of moisture. It’s used to release chemicals from sealants, lubricants or metals in the process called Outgassing. It’s also used to force volatile chemicals out of compounds in a Bakeout and to prevent reactions like oxidation.
See more in the infographic below.