Beyond Terpenes: The Emerging Science of Cannabis Flavor

Editor's note: This is Part I of a two-part series. You can read Part II, "The Flavor Labs Don’t Measure: What Is Terpene Testing Missing?" here. 

Terpenes are at the center of most conversations about cannabis flower tastes. The advent of terpene testing in cannabis was exciting and groundbreaking. Finally, we had a concrete way to describe why flower smells and tastes differently, and how those terpenes steer the “high.” Now that terpene testing has become standard practice, product labels, dispensaries, and educational materials consistently use terpene profiles to describe the smell and flavor of flower and extracts. (Although terpenes are also discussed in the context of the proposed entourage effect, their role in flavor is a separate question.) That has incentivized growers to prioritize high-terpene cultivars as well. In many ways, the terpene conversation has given the cannabis industry a more sophisticated language for discussing flavor than it had before. But now many commercial terpene products combine terpenes with additional flavor compounds. If terpenes alone could reproduce the lingering fruit, candy, or dessert flavors consumers seek, the market wouldn’t demand or support terpene formulations with additional flavor compounds.

Evidence from not only consumers but also sensory science, food chemistry, neuroscience, and plant physiology all point to the same conclusion: Terpenes are an important part of flavor but they are not the whole story.

Smell + Taste = Flavor
Many terpenes smell incredible but taste very unpleasant or bitter in isolation. Limonene on its own tastes sharp and bitter, not sweet and citrusy. Pinene tastes pretty bad, too, like bitter turpentine. A major source of confusion is the role of smell in flavor. Aroma is largely provided by terpenes, and flavor is a perceptual experience created when the brain combines taste, smell and retronasal olfaction into one sensation. Retronasal smell is simply the passage of aroma compounds from the mouth to the nose during consumption. The brain combines these aroma signals with taste and texture and other sensory information into the unified perception that we know as flavor. These sensations come together, and it is easy to confuse one with the other.

Being sick with a cold can make food seem nearly flavorless even though taste buds are still working just fine. Participants in sensory experiments can usually identify basic tastes while wearing nose clips, yet struggle to distinguish specific flavors such as cherry, grape, or lemon. Once the subject's smell is restored, those flavors become immediately recognizable. Taste is the foundation of flavor, while smell allows the brain to differentiate finer flavors.

A fascinating example of how smell and taste interact was shown by carrot researchers judging sweetness based on sugar and terpene levels. They were shocked to find the highest sugar concentrations (according to lab results) did not produce the sweetest perceived flavor. They realized higher levels of terpenes were making the carrots taste more bitter. So, they reduced terpene concentrations by about 24%, and that increased perceived sweetness even though sugar levels remained unchanged.

In other words, overall flavor comes from interactions among compounds rather than from any single molecule acting alone.

The Brain Creates Flavor
More than 40 years ago, psychologist Paul Rozin showed that smell is unique among the senses because it is routinely confused with taste itself. That confusion may help explain why consumers often describe cannabis as tasting like blueberries, citrus or pine, when much of that perception may actually be driven by aroma compounds reaching the nasal receptors during consumption. Surprisingly, Rozin also showed that the same odor can be sensed differently depending on context. Strong smells like aged cheese, fish, and eggs produce aromas that can smell rather unpleasant, but become delicious when combined with taste.

Today, neuroscientists consider flavor to be one of the most complex sensory experiences that humans have, integrating taste, smell, texture, temperature and prior experience into one perception. So, we should understand flavor as the chemistry of taste and smell filtered through human physiology and perception.

Cannabis is hardly the first crop to face this confusion. Blueberries, grapes, and wine have all been studied extensively, and the results all point in the same direction. Blueberries were found to contain several terpenes associated with desirable floral and sweet aromas, but the characteristic blueberry aroma emerges from hundreds of volatile compounds acting together rather than terpenes alone.   

Grapes and wine contain more than 550 volatile compounds, and terpenes are only a small part of the spectrum. Some of the compounds that matter most are barely there at all. And even highly aromatic Muscat wines could not be fully recreated using terpene mixtures alone.   

The Missing Pieces
Similar questions have driven decades of research in wine, coffee, and other flavor-intensive industries, revealing unexpected levels of complexity. Cannabis appears to be heading down that same path. Terpenes transformed the conversation by giving growers and consumers a common language, but every flavor-intensive crop studied so far has shown that no single class of compounds tells the whole story. Terpenes deserve their place in the conversation, just not as the whole picture.

Some compounds that shape flavor probably exist only in trace amounts. Others may interact with terpenes in ways that amplify, suppress, or transform perception, and some may still be unidentified. The inclusion of other flavor compounds in lab testing may change the way cultivars are bred, tested, and judged. Researchers are already beginning to look beyond terpenes toward esters, sulfur compounds, flavonoids, and hundreds of other molecules that may help explain why some cultivars stand out.