A terpene is a hydrocarbon assembled from isoprene (C5) units. Strictly, "terpene" means the pure hydrocarbon and "terpenoid" the oxygen-containing relatives, but growers use "terps" for both. Cannabis makes them in the same glandular trichomes as cannabinoids, using terpene synthase enzymes. More than 100 have been identified; a typical flower is dominated by a few, such as myrcene, beta-caryophyllene, limonene, terpinolene and the pinenes.
In practice
Total terpene content in dried flower is usually somewhere around 1-3% w/w, sometimes higher in fresh material. Monoterpenes are the most volatile and are lost first during drying, curing and storage; Ross and ElSohly found large monoterpene losses on air-drying. Slow, cool drying and a careful cure keep more of them. Terpenes explain much of a cultivar's smell, but not all: trace sulfur compounds and esters can dominate certain aromas.
Don't confuse with
- Terpenoid: an oxygenated terpene (linalool, bisabolol), often lumped in with terpenes.
- Cannabinoid: a different compound class, made in the same glands.
- Volatile sulfur compounds: tiny amounts drive the "skunk" smell, not terpenes.
Myth check
Terpenes on a label do not predict effects. House view: indica/sativa labels don't predict chemistry, and terpene-based effect claims are unproven. See Mythbusters.
A terpenoid is a terpene-derived compound that carries extra functional groups, usually oxygen (alcohols, oxides, ketones), such as linalool, bisabolol or caryophyllene oxide.A hair-like outgrowth of the plant's skin; in cannabis the glandular types make and store the resin holding cannabinoids and terpenes.A cannabinoid is any compound that binds the body's cannabinoid receptors or shares the typical cannabis terpenophenolic structure; the plant-made ones are phytocannabinoids such as THCA and CBDA.Beta-caryophyllene is a spicy, peppery sesquiterpene common in cannabis, notable as a dietary terpene that also binds the CB2 receptor in laboratory studies.Limonene is a monoterpene with a citrus aroma, found in citrus peel and many cannabis cultivars, where it is often among the top three terpenes.A monoterpene is a ten-carbon terpene made from geranyl pyrophosphate, such as myrcene, limonene, pinene or terpinolene; they are the most volatile terpenes and the first lost in drying.Sulfur (S) is a secondary nutrient taken up as sulfate, used in the amino acids cysteine and methionine; deficiency yellows new growth fairly evenly.Volatile sulfur compounds (VSCs) are trace sulfur-containing aroma molecules, especially prenylated thiols, that give cannabis its skunky, gassy smell at concentrations far below terpenes.A sesquiterpene is a fifteen-carbon terpene made from farnesyl pyrophosphate, such as beta-caryophyllene, humulene and bisabolol; they are heavier and less volatile than monoterpenes.A terpene profile is the measured mix of terpenes in a sample, reported as each compound's % w/w and the total, used to describe and compare cultivar aroma chemistry.Myrcene (beta-myrcene) is a monoterpene with a musky, earthy, ripe-fruit aroma and is the most common dominant terpene in commercial cannabis flower.
