Cannabis Aroma Is Shaped by More Than Terpenes
Terpenes are important contributors to cannabis aroma, but they do not fully explain why different varieties can smell so distinct. A 2023 study published in ACS Omega found that low-concentration, nonterpenoid compounds can have an outsized influence on the sweet, fruity, citrus, savory, and chemical aromas associated with cannabis.
The researchers analyzed the volatile chemical profiles of 31 ice hash rosin extracts and compared the results with sensory assessments. Ice hash rosin is a concentrated, solventless product made from cannabis trichomes, making it easier to detect compounds that may occur at very low levels. The samples represented a wide range of aromatic profiles, including varieties described as sweet or fruity, prototypical, and savory or chemical.
The study found that varieties with very different aromas often had broadly similar terpene profiles. That does not mean terpenes are irrelevant: compounds such as myrcene, limonene, and caryophyllene still contribute to cannabis’s overall scent. Rather, the findings suggest that terpene percentages alone may provide limited information about the specific characteristics that distinguish one variety from another.
Instead, the researchers identified a range of minor volatile compounds, sometimes referred to as flavorants, that appeared to help drive those differences. The compounds included esters, alcohols, and other nonterpenoid chemicals. Because some have very low odor-detection thresholds, even small quantities may strongly affect how a product smells.
Among the most notable findings was a class of volatile sulfur compounds containing a 3-mercaptohexyl functional group. These compounds were associated with strong citrus, tropical-fruit, sulfuric, or petroleum-like notes in some samples. The researchers also linked skatole, or 3-methylindole, with the pungent savory or chemical aroma detected in other varieties. Earlier work by some of the same researchers had identified a broader family of cannabis sulfur compounds, as described in this ACS Omega study on prenylated volatile sulfur compounds.
The results could eventually influence how cannabis is evaluated and labeled. Testing that reports only total terpene content may overlook compounds that play a major role in a product’s perceived aroma. More comprehensive chemical analysis could help cultivators and breeders select for consistent aroma traits, while laboratories and brands may use expanded profiles to improve product identification and quality control.
The findings also add to concerns about relying on the indica-versus-sativa distinction as a meaningful guide to cannabis chemistry or aroma. Those labels do not capture the full range of cannabinoids, terpenes, flavorants, genetics, and growing conditions that shape a product’s characteristics. The study, however, examined aroma chemistry—not psychoactive effects or therapeutic benefits—so it does not establish that these newly characterized compounds produce particular medical or intoxicating effects.
One important limitation is that the research focused on 31 ice hash rosin extracts selected for aromatic diversity. The results may not apply directly to every cannabis flower, concentrate, growing method, or processing technique. Additional studies, including work on standardized flower samples and larger collections of genetically related plants, will be needed to determine how consistently these compounds predict aroma across the broader cannabis market. A later study examining five phenotypes from the same genetic cross, published in ACS Omega, likewise found that minor nonterpenoid compounds helped distinguish aroma differences.
Overall, the research does not show that terpenes are unimportant. It shows that cannabis aroma is chemically more complex than terpene labels suggest. For consumers and the industry, a fuller picture may require looking beyond headline terpene percentages to the many trace compounds that give individual varieties their distinctive character.
