Vapor Pressure

Vapor pressure refers to the pressure exerted by volatile compounds in cannabis plant material when they transition from liquid to gas phase. This property is particularly relevant to cannabis terpenes and cannabinoids, which vary in volatility based on molecular weight and structure. Understanding vapor pressure helps breeders and cultivators predict how aromatic compounds will behave during drying, curing, storage, and processing. Terpenes with higher vapor pressures—such as limonene and pinene—volatilize more readily at lower temperatures, while heavier compounds remain more stable. Vapor pressure data informs decisions about harvest timing, post-harvest handling, and extraction methodology, making it a key parameter in breeding for specific aromatic or cannabinoid retention profiles.

Breeders track vapor pressure profiles when selecting for strains intended for specific end uses—fresh flower preservation, solvent extraction, or rosin production. Cultivars bred for maximum terpene retention in dried flower require different environmental controls than those developed for extraction, where volatile loss during processing is a consideration.