Science & Health
What Gives Marijuana Strains Their Distinctive Smells And Flavors? A New Scientific Review Sheds Light
A new scientific review takes a deep dive into the flavors and aromas of marijuana, examining how the plant’s genetic makeup, cultivation methods and post-harvest processing affect the various compounds that give cannabis products their distinctive palate.
The goal, it says, is to “support advancements in breeding programs, enhance product quality control, and guide future research in cannabis sensory science.”
A wide array of molecules—terpenes, flavonoids, phenols, aldehydes, ketones, esthers and sulfer-containing compounds—are behind the sensory profiles of cannabis, the study explains. Terpenes are the most prominent contributor to the plant’s bouquet, but authors point out that recent findings around other compounds “challenge the conventional focus on terpenes as the primary determinants of aroma, underscoring the importance of volatiles in shaping the aromatic complexity of cannabis.”
Production of those chemicals is determined through both a plant’s genes as well as its metabolic and environmental conditions, the review adds, meaning that maintaining “robust agricultural properties―such as optimized nutrient and water use, temperature tolerance, pest resistance, and shortened growth cycles—remains critical even as breeders reconfigure cannabinoid and aroma profiles.”
“While modifications to flavor traits and the cannabinoid content can enhance the product quality,” it says, for example, “there is increasing evidence that these traits are intertwined with plant stress responses and the overall cultivation performance.”
“The aroma and flavor of C. sativa L. are defining features that contribute to its identity, appeal, and potential therapeutic effects. These sensory attributes arise from a complex interplay of genetic, biochemical, and environmental factors, with terpenes, flavonoids, and other volatile compounds playing central roles.”
Plants can also be modified through genetic manipulation or post-harvest handling techniques. “By optimizing these variables,” the review explains, “it is feasible to enhance the profiles of aroma and flavor compounds.”
While gene-editing technology can revise the foundational makeup of cannabis plants, various environmental factors—ranging from differences in light wavelengths, soil composition and water availability, among others—can also significantly affect terpene levels, it continues, highlighting the roles of UV light and various soil nutrients.
“Combining these methods―genetic selection, optimized cultivation practices, and meticulous post-harvest techniques―yields the most effective results,” authors wrote in the new paper. “For example, selecting varieties with high terpene potential, cultivating them under specific light and nutrient regimens, and employing precise drying and curing methods can maximize the aroma and flavor qualities of cannabis.”
The review, by four independent researchers in Switzerland and Germany along with the founder of the Spanish plant science firm SeedCraft, was published late last month in the journal Molecules.
“By leveraging advances in genetics, agronomy, and post-harvest handling,” it says, “it is possible to not only preserve, but also enhance the terpene profiles of C. sativa L., ultimately improving the sensory experience for consumers and expanding the applications in both the medicinal and recreational contexts.”
Compounds that imbue cannabis with its smell and flavor are also prone to degradation, the result of factors like light, heat, oxygen and humidity. Many volatile chemicals, for example, are lost when products are exposed to heat.
“Regarding light exposure,” the paper adds, “UV and other light wavelengths can catalyze photochemical reactions, leading to the breakdown of terpenes and the formation of undesirable byproducts. For example, limonene can oxidize under UV exposure to produce terpinolene or other oxidized derivatives, altering its citrusy aroma.”
Oxidization, it continues, “not only reduces terpene concentrations, but also generates additional compounds with different sensory properties, such as alcohols or ketones, which can alter the aromatic characteristics and perceived flavor of cannabis products.”
Preservation strategies might include novel packing methods, refrigeration or freezing, removing oxygen from packaging, freeze-drying or so-called microencapsulation or nanoencapsulation, where desired compounds are embedded in protective carriers.
Cannabis growers and others would benefit from a flavor wheel mapping marijuana aromas, similar to standardization practices in wine, coffee, tea and tobacco, authors wrote: “Consumers receive a tool to match preferences with effects, while researchers benefit from a standardized system that aids data comparison and advances the scientific understanding of the cannabis aroma and flavor.”
To that end, the researchers also published a map intended to visualize the flavor and aroma descriptors of various commercially available terpenes. “For example, the descriptors floral and lavender are frequently used for linalool,” the paper says; “citrus, lemon, and orange are frequently used with limonene; pine is frequently used with pinene; earthy and woody are frequently used with humulene; and woody, spicy, and peppery are frequently used with caryophyllene.”
The new review says future research “should continue to explore the interactions between compounds, the environmental factors influencing their production, and the development of preservation techniques to maintain their stability,” with authors opining that the “application of cutting-edge technologies, such as synthetic biology and computational modeling, holds promise for optimizing aroma and flavor profiles while ensuring product quality and consistency.”
And while a “comprehensive aroma wheel” would be “desirable within the field,” the paper says, developing one might be a challenge. “It is posited that an extensive study encompassing various strains, trained sensory panelists, and detailed metabolomic analysis is essential to ensure accurate representation,” it says.
“This review highlights the complexity and significance of cannabis aroma and flavor, emphasizing the need for continued collaboration between researchers and industry stakeholders,” the review concludes. “By addressing these challenges, the cannabis sector can unlock new opportunities for product development and scientific discovery.”
A separate study by a California graduate student, meanwhile, recently found that incentives in the legal marijuana market—such as the desire for plants to mature faster and produce more cannabinoids for extraction—may be leading to a decline in global biodiversity of the plant.
That paper noted that while humans have been selectively breeding the cannabis plant for thousands of years, breeders in what it refers to as the “post-prohibition” era have optimized for a handful of traits, such as a high proportion of flowers as opposed to stalks or leaves, maximum cannabinoid content, a “desirable suite” of aromatic terpenes and a reproducible chemical profile.
Amid an upswing in marijuana research in the post-prohibition era, researchers are still unlocking new secrets about the cannabis plant. Researchers earlier this year, for example, announced that they successfully identified a new cannabinoid—cannabielsoxa—produced by the marijuana plant as well as a number of other compounds “reported for the first time from the flowers of C. sativa.”
Other research in 2023, published by the American Chemical Society, identified “previously undiscovered cannabis compounds” that challenged conventional wisdom of what really gives cannabis varieties their unique olfactory profiles.
As for other recent cannabis research, scientists reported in May that they identified 33 “significant markers” in the cannabis genome that “significantly influence cannabinoid production”—a finding they say promises to drive the development of new plant varieties with specific cannabinoid profiles.
Among the findings were what the paper called a “massive” set of genes on one plant chromosome that involved about 60 megabases (Mb) and was associated specifically with THC-dominant cannabis strains.
The article said the results “offer valuable guidance for Cannabis breeding programs, enabling the use of precise genetic markers to select and refine promising Cannabis varieties.”
While research into marijuana has exploded in recent years as the result of more jurisdictions legalizing the drug for medical and adult use, it’s unclear how the Trump administration’s priorities will impact that trend.
For example, under the new administration, “marijuana” is also now one of nearly two dozen “controversial or high-profile topics” that staff and researchers at the National Cancer Institute (NCI) are required to clear with higher-ups before writing about.
