Decoding the Mysteries of Cannabis's Skunky Smell

Not unlike wine, most high-end cannabis is determined by its specific aroma, whether it’s the distinctive “gas” of an OG Kush or Sour Diesel or the citrusy notes of the fruitier varieties. Perhaps no scent is more distinctive — or polarizing — than that of the Skunk varieties. Yet it’s only up until now that researchers are beginning to tease apart the actual compounds in the plant that give the plant its pungent smell.

And believe it or not, it’s not the terpenes that are responsible. A November paper published in ACS (American Chemical Society) Omega points to a family of volatile sulfuric compounds (VSCs), clinically observed for the first time, that accounts for the scent. Authored by a team at the cannabis research firm Abstrax that includes ‘90s cannabis vet/OG Kush originator Josh del Rosso, this paper breaks down for the first time the molecular components behind the skunk scent, and points to a future when preservation of these VSCs can create more potent products. As Abstrax Chief Scientific Officer Kevin Koby told the Daily Mail, “It will help brands maximize their products and literally push cannabis quality to the next level,'

HOW THEY DID IT

Popular wisdom among cannaseurs maintains that top-shelf flower will almost always contain a strong scent. These scents often come into play during catered, infused meals where fine food is paired with certain kinds of cannabis flower. And chances are if you’re putting your joints in a humidor, or storing your flower in dark, cool places, you’re attempting to preserve these compounds for as long as possible. For just as important as potency to experienced consumers is taste, and smell accounts for 80% of the aftertaste of a favored product.

You’ve heard about terpenes like linalool and pinene, which can contribute strongly to a flower’s scent. However, they do not account for the entirety of a cannabis plant’s aroma. Until now, the exact components of the pungent skunk smell remained a mystery. To uncover it, the Abstrax team utilized two-dimensional gas chromatography, time-of-flight mass spectrometry, flame ionization detection, and sulfur chemiluminescence. Going in, the team knew that strong-smelling plants like durian, garlic and hops — not to mention the spray emitted by actual skunks — possessed high concentrations of VSCs. So their tests focused on examining this hypothesis.

The team then searched for and analyzed the presence of VFCs in three manifestations of cannabis. One was store-bought cannabis flower like Black Jack, Bacio Gelato and Cali Berry from Southern California-based dispensaries such as Sherbinski’s, Cookies and Jungle Boys. The other manifestation was in the form of three butane hash oil cannabis extracts. Finally, the team also measured the presence of VSCs in an indoor greenhouse to determine the life cycle of these VSCs — when they are most prevalent during a plant’s growth and what happens to them once the plants are cured and stored.

THE RESULTS

During the cannabis flower portion of the paper’s inquiry, many different VSCs were observed, and not all of them lasted long enough (remember, these compounds are volatile) to be identified. However, four major VSCs, labeled in the paper as VSC3-4 and VSC6-7, were detected, with VSC3 being the most prevalent in Bacio Gelato, the most pungent of the cannabis strains (pungency was rated on a scale of 0-10 by a four-member “olfactory panel”). All of these VSCs bore a strong resemblance to compounds found in garlic, some of which possess known health benefits. For instance, VSC7’s structural analog in garlic, diallyl disulfide, may aid in cardiovascular health and guard against colorectal cancer.

As it turns out, the three Sherbinskis cannabis concentrates, when screened using gas chromatography, also exhibited several of the VSCs found in their cannabis flower precursors. When VSCs were measured in the greenhouse portion of the paper, the researchers discovered that “the concentrations of these compounds increased substantially during the last weeks of the flowering stage, reached a maximum during curing, and then dropped after just one week of storage.”

Perhaps the most prevalent of all the VSCs in the skunkiest samples was VSC3, or 3-methyl-2-butene-1-thiol to its friends. And at high concentrations, VSC3 did rate as particularly sulfurous to the paper’s panel. However, the researchers noted that a plant’s scent is complex, and that when mixed with the other VSCs identified in the paper, VSC3 could contribute to subtle aromas “mildly reminiscent of a flower.”

WHAT’S NEXT

Now that this new class of aromatic compounds have been shared with the world, enterprising cultivators and packagers can now get to work. For starters, the paper found that the oldest cannabis flower sample measured possessed a relatively high concentration of VSC3, which the researchers surmised could be due to its storage in a plastic jar with a “heat-sealed, airtight aluminum film,” rather than a mylar Ziploc bag like many of the other samples. As researchers continue to study how these new VSCs work in the body, new applications for human health may be discovered along the way as well. This will certainly please anyone fond of what may turn out to be cannabis’s not-so-sweet smell of success.