The Nose Knows Which Cannabis Products Will Feel Good, Study Finds

What makes a “quality” cannabis strain? Is it a high THC content? A certain terpene profile? According to a new study published in Psychoactives, the most significant predictor of a cannabis strain’s appeal is its smell.

Based on data generated by volunteer judges at a local craft cannabis competition, researchers determined that THC dose, THC potency, and total terpene content had no significant correlation with whether the judges reported an enjoyable experience. However, a pleasant aroma was positively correlated with reports of pleasant subjective effects.

This finding could have wide-reaching implications for public health, the researchers say, as the results appear to support a growing industry campaign to de-emphasize THC in the marketplace.

Pleasant subjective aromas predict a pleasant experience

This study looked at 278 cannabis samples that had been entered into the 2019 and 2020 editions of the Cultivation Classic cannabis competition, held annually in Portland, Oregon. As a part of the competition, all samples were sent for cannabinoid and terpene analysis at a third-party testing laboratory.

A total of 276 volunteer competition judges were each given a sample kit containing samples from between 8 to 10 cannabis strains entered into the competition. Over the course of approximately one month, the judges were asked to use each sample and then answer an online questionnaire about each sample’s subjective effects and desirability. This included ranking the appeal of each strain’s smell and overall effects, as well as noting any changes to mood. Additionally, the judges were asked to record what method of consumption was used.

The study authors used this information to compile a “composite appeal score” for each sample, which could then be compared against other factors such as the cannabis strain’s potency.

They found that a pleasant aroma was the strongest contributor to subjective appeal. The strains that smelled the most appealing were the most likely to result in desirable subjective effects and positive mood. The researchers also found that there was a high degree of consensus about which strains smelled pleasant.

Want a feel-good strain? Ignore the THC label

In the current legal cannabis market, consumers are generally willing to pay higher prices for higher-potency cannabis. This has led to THC potency becoming a de facto quality indicator, driving the high demand for high-potency products and forcing potency to become a major factor in purchasing decisions.

“Our analysis revealed that, contrary to both market dynamics and consumer perception, neither THC potency nor THC dose had an impact on subjective appeal,” the researchers wrote. “In the context of naturalistic recreational enjoyment, some hemp-like chemovars [...] were just as appealing as chemovars with 20% THC or more.”

In recent years, terpenes have also become an important metric in the cannabis market. These volatile compounds are thought to be responsible for the flavor and aroma of cannabis. Many terpenes are known to have therapeutic properties when isolated. However, despite the terpenes’ role in cannabis aroma, this study found that total terpene content was not associated with an increased subjective appeal.

This lack of relationship between subjective appeal and THC potency, THC dose, and total terpene content may have important consequences for public health, the researchers say. Past research has linked the frequent consumption of high-potency products to poor mental health, as well as substance use problems and an increased risk of psychosis.

The study’s findings could also support existing efforts to de-emphasize high-THC products in the marketplace.

“The market here is dominated by THC, when really the sophistication of the chemistry within the plant is such that you should be evaluating the quality of your cannabis-based on something much broader; ​​based on a broader set of data points that give you a more specific indication of what the effects will be,” Jeff Gray, co-founder of SC Labs, told Analytical Cannabis earlier this year.

The researchers suggest that the strong emphasis placed on aroma might mean that the cannabis industry could benefit from adopting a model where cannabis is sold in a way where consumers can smell the flower before purchase.

Unraveling the complex odor of cannabis

Cannabis odor is clearly an important building block of the consumer experience. But understanding cannabis’ unique smell is also essential for tackling industry-level issues such as terpene drift, as Dr. William Vizuete, chief scientific officer at the odor mitigation company Byers Scientific, previously told Analytical Cannabis.

“What we’ve been looking at lately is terpene drift, or the eucalyptol that’s being emitted by the cannabis,” Vizuete said. “We need to know what those emissions of those molecules are by strain and plant’s life cycle. And there’s hundreds of different strains, which means there could be hundreds of different kinds of profiles.”

Terpene drift has become a hot topic as cannabis reform has allowed for large-scale, outdoor, legal cannabis and hemp farms to set up shop. Given the high numbers of volatile organic compounds that are produced by the cannabis and hemp plant, there was a fear that these could taint other nearby agricultural crops. Though one recent study on a hemp farm and nearby wine grape farm did not find this terpene drift to be an issue, research into cannabis odor and the various factors which may affect terpene drift is still very much in its infancy.

For example, it was only last year that scientists discovered what is responsible for cannabis’ distinctive skunk-like odor — not terpenes, but volatile sulfur compounds (VSCs). And according to Dr. Alex Guenter, Byers’ senior scientist, studying these sulfur-containing thiol compounds can be very tricky.

“Odor perception is related to the mixture of compounds, the ratios of the terpenes. And the thiols are really important for how we perceive odors. And so we need to know the starting point, which is how the ratios are coming off these different plants,” Guenter explained.

“And it’s a real challenge because the thiols are present a thousandfold less than the terpenoid compounds. It’s like looking for a needle in a haystack.”