A vacuum oven gently heats cannabis flower to create concentrated, potent extracts like shatter or wax. Unlike traditional ovens, a vacuum environment removes oxygen, lowering internal pressure and boiling points. This reduced pressure accelerates the evaporation of excess moisture and residual solvents. Extract producers use vacuum ovens to fully purge and winterize extracts for purity, consistency, and safety. Gentler temperatures also preserve fragile terpenes and cannabinoids while eliminating contaminants. Closed loop recovery systems capture evaporated ethanol. While expensive initially, vacuum ovens ensure critical extraction purity for legal markets. They also enable niche post-processing like low-temperature terpene retention based on compound volatility.