The world of cannabis is as diverse as it is fascinating, with each flower or extract offering a unique sensory experience. For years, a few terpenes were hailed as the primary contributors to the distinctive aromas of different cannabis chemovars or varieties. However, a groundbreaking study published in ACS Omega reveals that minor, non-terpenoid compounds play a significant role in shaping the exotic scent associated with your favorite strains or varieties of cannabis. This new understanding promises to help change the way we perceive and classify cannabis varieties.

The Terpene Tale

Traditionally, this smelly discussion has focused on terpenes—organic compounds found in various plants, including cannabis—as the key players in the plant’s aromatic profile. Terpenes like β-myrcene, D-(+)-limonene, β-caryophyllene, and terpinolene were thought to define the unique aromas of a particular flower or extract. However, while these compounds contribute to the general scent of cannabis, they fall short of explaining the rich and varied aromas of different samples. The three or four most common terpenes cannot not explain the spectrum of scent from sweet-berry-like to earthy-skunky, and all the way to savory-garlic-like aromas. With a wide spectrum of smell, it is no wonder that modern cannabis varieties are often described as exotic.

Non-terpenoid Compounds: The Hidden Smell

The study delves into the volatile chemical profiles of 31 different cannabis ice hash rosin extracts, uncovering the importance of non-terpenoid compounds in determining aroma. The researchers obtained samples from dispensaries around the Los Angeles, CA area. Samples were chosen to maximize the diversity of aroma attributes. The products were subjected to a sensory analysis by a panel of seven cannabis users (good work if you can find it!). Each panelist reviewed the aroma of each product independently, the results of their sensory analysis are included in the supplemental information for the study (See Page S6). The products were also analyzed with scientific instruments.

The minor, volatile compounds, though present in low concentrations, were shown to have a profound impact on the scent. Two standout groups identified are the volatile sulfur compounds (VSCs) and skatole (3-methylindole).

Volatile Sulfur Compounds (VSCs): These compounds, particularly those containing the 3-mercaptohexyl functional group, impart strong citrus and tropical fruit aromas to varieties. The VSCs also get a bad reputation as this class of molecule underlies bad breathe. Garlic Cocktail #7 and Gorilla Glue are known for pungent citrus scents from their assortment of VSCs. The savory skatole compound is a key player in the aromas of strains like GMO, GMO Cookies, and 710 Chem.

Variety Spotlight and Aromatic Profiles

Let’s take a closer look at some cannabis varieties (i.e., strains) and their unique aromatic profiles, shaped by these non-terpenoid compounds. Here are some of the takeways from the research article:

Dogwalker OG: Known for its skunky and woody aroma, Dogwalker OG shares its D-(+)-limonene/β-caryophyllene cluster with the citrusy Tropicana Cookies, showcasing how diverse scents can emerge from similar terpene profiles.

Purple Punch: This strain delights with a sweet, grape-like scent, yet it too falls within the same terpene cluster as Dogwalker OG, highlighting the influence of other compounds.

Garlic Cocktail #7 and Gorilla Glue: The distinct tropical and citrus aromas of these varieties are driven by VSCs, challenging the traditional focus on terpenes.

GMO, GMO Cookies, and 710 Chem: These strains are characterized by savory, chemical aromas due to high levels of skatole, a stark contrast to the fruity profiles of others.

Fruity Pebbles and Garlic Cocktail #7: Despite containing skatole, these strains rank high in exotic scores due to the interplay with other flavorants and VSCs, resulting in a complex bouquet of scents.

The New Frontier in Cannabis Classification

The findings from this study underscore the need to look beyond terpenes when classifying and appreciating cannabis strains. The unique aromas of cannabis are a symphony of various compounds working in harmony. For instance, the presence of esters, which contribute fruity and sweet notes, is significant in Banana Scream, which boasts over 15 different esters.

This deeper understanding of cannabis phytochemistry not only enriches our sensory experience but also has practical implications. For consumers, it means more accurate information about what to expect from an exotic aroma. For producers and marketers, it offers a new angle for distinguishing their products in a crowded market.

Conclusion

Cannabis is more than just its cannabinoids and terpenes. The intricate blend of minor, non-terpenoid volatile compounds plays a crucial role in creating the diverse and exotic aromas. This helps to explain why two varieties with the same major terpenes can smell remarkably different. As our knowledge expands, so too does our appreciation for this plant. Whether you’re a casual consumer or a connoisseur, this new perspective invites you to explore the rich aromatic tapestry like never before.

So next time you encounter a variety with an unforgettable scent, remember: it’s not just the terpenes at work, but a symphony of compounds coming together to create a unique sensory experience. Happy exploring and stay curious!

Figure 5 Showing the key volatile compounds producing specific aromas, from the article Oswald, I. W. H. et al. Minor, Nonterpenoid Volatile Compounds Drive the Aroma Differences of Exotic Cannabis. ACS Omega 8, 39203–39216 (2023).