Lactones, Ketones, and Phenols: The New Language of Cannabis Aroma

Nearly everyday, we're learning something new about the cannabis plant as science digs deeper into its biology, chemistry, and the myriad ways it can be used medicinally. Though not yet fully mapped, the hundreds of compounds produced by the whole cannabis plant are consistent in one thing: each new discovery brings with it the potential for not only a greater understanding of the plant, but the potential of new modalities for human use.

In adult use markets, there are products for all cannabis appetites. And to enhance the diverse array of offerings, the trendy focus on terpenes — the aromatic compounds that give each cannabis strain its flavor and nuanced effects — has allowed consumers to expand their understanding of the plant beyond the simple indica/sativa binary.

Equipped with this knowledge, cannabis consumers have developed a more sophisticated vocabulary around taste, aroma, and effects. But what of the dozens of other chemicals that the cannabis plant produces? After all, like other plants, cannabis contains dozens of other types of compounds, beyond just its active cannabinoids and terpenes. 

Learning more about these other components could grant us a deeper comprehension of the entourage effect — the symbiotic relationship among all the compounds in cannabis, such that the resulting impact is greater than the sum of the individual parts. 

What are some of the other notable compounds in cannabis?

A number of science-driven cannabis companies are pursuing research to drive smarter products and better outcomes for consumers. 

“Cannabinoids and terpenes are only part of the whole that makes up the cannabis plant," Ben Cassiday, co-founder of online retailer True Terpenes, and chief science officer David Heldreth told Civilized. "Things [that] we believe are terpenes now, such as menthol, citral, and eugenol actually aren't. Menthol and citral are actually terpenoids, a class of compounds that contain terpene structure or are made from terpenes. Eugenol is actually a phenolic compound, and not a terpene either." 

Phenolic compounds, sometimes known as phenols, are aromatic, and much like terpenes, they are present in many other plants. Two common examples of phenols are wine grapes’ resveratrol and aspirin's salicylate, which can come from willow bark. They are a form of reactive, acidic, molecules where a hydroxyl group attaches to hydrocarbon, and some are potent antioxidants. 

One 2018 paper from Bentham Science Publishers sought to identify phenols among the 480 chemicals in cannabis. They concluded that the plant is as defined by its non-cannabinoid components as its 100 identified cannabinoids. 

“Things like ketones, phenols, esters, flavonoids and the like provide more of the flavor picture," the True Terpenes team said. "If [cannabis] flavor were music, terpenes would be the brass and woodwinds — which may carry the melody — but you need percussion and bass from these other instruments/compounds to carry the piece, or flavor.”

Ketones and lactones are slightly different than the other aromatic molecules. Lactones are carboxylic esters — organic compounds in which an acid's hydrogen is replaced by an alkyl or other organic group — which lead to a fatty alcohol that can cause creamy, buttery, cheesey, or fruity flavors, like that of a coconut or passion fruit. Lactones are widely used in the fragrance and flavor industries, are are responsible for classic scents such as faux coconut in sun care products and those peachy perfumes that were popular in the early aughts. 

In cannabis, lactones are rare, but can drop in those cheesy, funky, or even fruity notes with force. Heldreth told us that since there is currently only one lactone found in cannabis — 2-c-methyl-aldoteronolactone — our flavor journeys may instead follow the paths of phenols and ketones more closely than that of lactones. 

Ketones are widely scrutinized right now as part of a Ketogenic diet, where, via food intake, the liver is encouraged to create ketones for energy from fatty acids, versus our more typical method of generating energy from burning carbohydrates. Ketones are solvent chemicals that contain carbon and can come in the form of everything from a sugar to an alcohol. Even nail polish remover is a ketone.

Heldreth says this class of chemicals could help us follow future flavor trends. “Ketones, [which] include things like 2-heptanone, have a banana-like flavor, and phenolic compounds include things like eugenol, which is an herbal, earthy aroma," he said. "I think both will see increased use in cannabis products, and use will just depend on the popularity of a particular flavor at a particular point in time.”

How do these chemicals influence cannabis’ flavor?

Now how does this apply to your everyday Blue Dream or Sour Diesel? 

True Terpenes has begun to include these chemicals in their strain profiles, which are terpene based blends for cannabis product manufacturers (but their "strains" are not cannabis, in and of itself, just formulations of terpenes that are specific to certain cannabis strains). This allows cannabis products to be finetuned as much as possible. Using these other aromatic compounds, the True Terpenes team explained, "will bring us more directly to comparing these [cannabis] flavors to fruits, foods and other things we use in our daily life.”

Getting closer to other craft production industries is precisely where many cannabis connoisseurs and experts want to see education progress. “As we fill in the gaps in the flavor of cannabis, things like the subtle peach flavors, or even a mushroom like umami that you might discern from your favorite outdoor cultivator will begin to find their way into the larger cannabis lexicon — -similar to wine, coffee or craft beers," Heldreth and Cassiday told Civilized. "It’s the beginning of a shift towards recognizing the impact of things like terroir on our food supply and everything we consume." 

Fuller flavor is the goal of any farmer making a consumable product, and cannabis is no different. 

“The limit really is our imagination. These compounds are responsible for the taste and aroma of everything we consume in our daily lives already, regardless of our awareness," Heldreth said. "As we begin to pull apart which compounds are individually or synergistically creating the specific tastes we are hunting for, we will be able to more accurately recreate cannabis varieties.”

Companies like True Terpenes may be doing this research to create ancillary products, but this intensive knowledge will only open up descriptors and language for everyone along the way, and go where traditional science is simply not interested to go at the moment.

Consumers can use this information to treat cannabis like fine wine, but it would also be wise for all parties to figure out if these molecules also contribute to cannabis’ psychotropic, psychedelic, and medicinal functions, and precisely how they do so. 

In the case of cannabis, flavor and function are sometimes dependent on each other, such as the floral funk of the terpene linalool, which many find calming and anxiolytic. As we gather data on all the constituents of this plant, the next few decades of medicine, adult use, and culture could shift forever. 

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