Demystify Terpenes With Cannabis Fragrance & Flavor Groups

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Creating a classification system that simplifies and groups terpene fragrances and flavors can improve consumer confidence, marketing and sales.

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The variety of aromas and tastes Cannabis produces leave lasting impressions on consumers, creating links between that fragrance and the plant’s desirable effects in the consumer’s mind. But the plethora of retail choices proves overwhelming to many. While industry transparency is improving, as many producers now list key terpenes present in various cultivars, many consumers don’t know what aromas and flavors those individual terpenes produce. Establishing an industry-wide system of Cannabis Fragrance & Flavor Groups that encompasses variation while informing and streamlining choice could help consumers make more informed selections and have a better understanding of what they like.

Terpene fragrances and flavors can be influential marketing tools. For example, the craft brewing industry increasingly focuses on beers brewed with aromatic hop cultivars rich in myrcene, caryophyllene, humulene and limonene, the terpenes prominently and widely distributed in both hemp and hops as well as several other minor terpenes also found in sinsemilla flowers. Myrcene-rich Citra hops also contain linalool and geraniol, imparting a citrusy tropical fruit aroma and flavor. Hop cultivars and their associated fragrance and flavor descriptors are increasingly featured on beer labels and menu descriptions, and are rapidly becoming determining factors in consumer choices. The brewing industry assigns hop aromas to broadly accepted categories—herbal and grassy, woody and spicy, floral, fruity and citrusy as well as earthy. Similarly, the perfume industry divides fragrances into green, woody, spicy, floral, fruity, oceanic and citrus. Wine producers have long used flavor descriptions to help consumers select between an otherwise confusing array of options to simplify choices, helping establish preferences between an oaky chardonnay or a buttery varietal, for example. The cannabis industry would benefit from a similar system.

We have created and are proposing a simple classification system that could be used in cannabis to improve marketing and educate consumers about which flavors and fragrances they can expect from specific cultivars. We began by seeking information from three primary sources: Laboratory analyses gleaned from published research and industry websites provided data as to the identity, amount and occurrence of terpenes in differing Cannabis landraces and cultivars. We collected aroma and flavor descriptors from fragrance and flavoring sites that describe and categorize thousands of chemical compounds, including the terpenes produced by Cannabis. And, we gathered consumer data from published surveys.

The terpenes found in Cannabis plants are each assigned by experts to one of 14 established fragrances and flavorings industry categories, which we condensed into five Cannabis Fragrance & Flavor Groups, described in detail throughout this column. The most commonly cited descriptors are in bold. The five groups encompass most of the aromatic variation found in modern sinsemilla as well as genus Cannabis in general. Finally, we chose foundational cultivars that are characteristic of each group, which are detailed in the graphics throughout this column.

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The Science Behind Cannabis Terpenes

The characteristic aromas of cannabis flowers and products are largely those of terpenes—aromatic hydrocarbon compounds of low boiling point found in plant essential oils and often named after the plants from which they were first isolated—and their complex names can, at times, seem daunting. Terpenes are often employed as fragrances, flavors, solvents, antiseptics and insect repellants. The most volatile and aromatic terpenes are the smaller 10-carbon monoterpenes that also tend to be highly unstable when exposed to room temperature (about 70 degrees F). The larger and generally less volatile 15-carbon sesquiterpenes can be somewhat less aromatic than monoterpenes but are more stable. The essential oil of a single Cannabis plant can contain about 150 different terpenes, and each is produced in differing concentrations from merely trace amounts to nearly 80%.

The trademark aroma and taste of each cultivar is established by its terpene profile, which also determines which fragrance and flavor group a cultivar is most closely associated. The major monoterpenes found most often and in the largest amounts are myrcene, limonene, pinene, terpinolene, ocimene and linalool, while caryophyllene and humulene are the more prevalent sesquiterpenes. Yet many more terpenes from both classes contribute to the complex aromas of individual cultivars.

Myrcene is the most prevalent terpene in the female flowers of both Cannabis and closely related Humulus lupulus or Brewer’s Hop. It has a spicy, musky, earthy, peppery, balsamic and root-like aroma with herbaceous, woody, rosy, clove, citrus, mango, grape, peach, vanilla, wine, mint, celery and carrot nuances. Myrcene’s combination of simultaneously dank, herbal, spicy, woody, floral and fruity flavors can be experienced in both sinsemilla and beer. The market is flooded with sweet floral-fruity cultivars, the majority of which are high in myrcene. Why grow and sell only ubiquitous myrcene-dominant flowers like so many others when there are other choices? Other terpenes such as terpinene also produce a wide range of aromas, and, like myrcene, are difficult to categorize, confounding the concept of assigning cultivars to discrete groups. However, the majority of terpenes are more easily classified, and can more confidently be considered characteristic of a single fragrance and flavor group.

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Dank Group

The Dank Group encompasses musty, earthy and organic type aromas that evoke memories ranging from grandma’s musty basement to delicious, fermented foods and beverages, seductively musky perfumes and pungently skunky odors. Although “earthy” is a descriptor frequently recognized by cannabis consumers, the Dank Group is strongly identified with only two minor terpenes, although others either solo or in concert could also impart the dank aromas. Terpinen-4-ol smells musty and dusty and spathulenol has an earthy, herbal and fruity aroma. Dank aromas may also be attributed to non-terpene compounds, and funky odors also can emanate from other sources such as bacterial and fungal spoilage rather than the flowers themselves.

Green-Herbal Group

The basic cannabis aroma is frequently described as “green,” as in plant-like, and the descriptor “herbal” is also commonly used, hence the Green-Herbal Group. Several terpenes with green and/or herbal aromas are found in Cannabis flowers, but green and herbal aromas can also indicate unripe flowers harvested prematurely. The Green-Herbal group is populated by minor terpenes, and although once more common, especially in imported cannabis, it is presently one of the less prevalent fragrance and flavor groups.

Several terpenes are commonly involved in creating the Green-Herbal fragrances and flavors, although they also may share characteristics with other groups. Phellandrenes and camphene are highly volatile monoterpenes. Alpha-phellandrene has a green-herbal, citrusy, turpentine and black pepper-like fragrance and flavor, while its isomer beta-phellandrene presents a minty, balsam and turpentine aroma. Camphene produces similar pungent, green-herbal, woody, pine and fir needle aromas with hints of spicy turpentine, citrus and mint, and a minty flavor with citrus and spicy overtones. Phellandrenes and camphene share many aroma characteristics with the Gassy Group, noted below.

Farnesenes, selinene and eudesmol are sesquiterpenes of the Green-Herbal Group. Alpha-farnesene has a woody, green, vegetative aroma with flowery, herbal, citrus, lavender, bergamot, myrrh, neroli, gin and apple nuances, and a fresh, green, vegetative flavor with hints of celery and hay and somewhat fatty tropical fruit after notes. Beta-farnesene, which is also a common aroma ingredient in hops, expresses a green, woody and vegetative aroma with hints of lavender and citrus, and an herbal flavor with organic woody notes. Farnesenes are primarily classified as Green-Herbal but also share some characteristics with the Floral-Fruity Group, noted below. Alpha-selinene’s aroma resembles warm amber, while beta-selinene has an herbal aroma. Eudesmol expresses a green and herbal as well as a woody aroma.

* Lower numerical value listed next to flower aroma descriptors correlates with a higher frequency of occurrence for each of the 48 aroma descriptors noted by fragrance testers and reported by Gilbert and Di Verdi 2018 – Bold descriptors among top 20 noted by testers.

Woody-Spicy Group

In addition to green and herbal, traditional imported marijuana often had a characteristic woody and/or spicy aroma, and these aromas are pronounced in today’s sinsemilla varieties with narrow-leaflet landrace heritage. The descriptors “woody” and “spicy” frequently appear in consumer surveys, and several terpenes fall into the Woody-Spicy Group.

Alpha-pinene is the most common terpene in the plant world and accounts for the woody aromas of many plants from pine to hop. Its aroma includes a slight cooling camphor nuance and a fresh herbal lift, and its flavor is intensely woody and piney with camphor and turpentine notes, and herbal, spicy and slightly tropical nuances. Closely related beta-pinene has a strong, cooling, herbal, dry-woody, green-hay, resinous, piney, turpentine-like, fresh, minty, eucalyptus and camphor aroma with spicy, black pepper and nutmeg nuances; and a fresh, piney and woody, turpentine-like resinous flavor with slightly spicy, mint and camphor nuances. Terpinolene is another monoterpene with a fresh turpentine aroma often described as woody or smoky, and, like pinenes, fits neatly within the Woody-Spicy Group.

Major sesquiterpenes also contribute to the woody and spicy fragrances and flavors. Caryophyllene has a spicy, sweet, peppery and woody aroma of dry cloves; and a peppery, spicy flavor with camphor and astringent citrus undertones, and is considered responsible for the “hoppy” aroma of beer. Terpenes structurally related to caryophyllene include iso-caryophyllene and caryophyllene oxide with its fresh, dry and woody, spicy sweet aroma with lemony notes; and a dry, woody, carrot flavor. Humulene is an isomer of caryophyllene with a woody, bitter and hoppy aroma, and the two often occur together.

Although they occur in smaller concentrations, several minor terpenes also contribute to the woody-spicy aromas. Cedrene isomers account for the woody, sweet, fresh cedar wood aroma; while aromadendrene, bergamotene and muurulene also have woody aromas. Guaiene has a woody aroma with balsam and pepper nuances. Guaiol has a woody, tea and rose aroma, but with some added floral and fruity characteristics. Thujene has a woody, green-herbal, cedar needle aroma; and sabinene has a woody, spicy, citrus aroma with green, oily and camphor-like nuances.

Monoterpene alcohols are highly volatile and slightly water-soluble compounds that often present with particularly strong aromas. Borneol expresses a balsamic, woody aroma with camphor, menthol, pine and mint overtones, and a burning, peppery flavor. Closely related bornyl acetate has a woody, balsamic, spicy-sweet, herbal, pine and cedar aroma with gin-like nuances. Fenchol is an isomer of borneol, with a dry, sweet, camphor-like, woody-pine and lemon scent. Structurally related fenchone shares similar camphor-like, earthy and herbal aromas with hints of cedar needles; and a cooling, camphor-like, sweet and minty flavor with musty, earthy undertones. The complex aromas of borneol and fenchol also contribute to the dank and gassy aromas. Terpinen-4-ol has a spicy, woody, earthy, musty, pepper aroma with sweet, citrus and menthol notes, and a cooling, woody, earthy, clove and spice flavor with a citrus undernote. Eucalyptol expresses the characteristic herbal, spicy, minty-camphor aroma of eucalyptus leaves and cloves; and has a spicy, cooling taste. Eucalyptol is also in part responsible for gassy aromas.

Floral-Fruity Group

Popular “sweet dessert” cultivars are prime members of the complex Floral-Fruity Group, and many terpenes are involved in creating the “sweet” aromas of our favorite flowers and fruits. “Floral” and several “fruity” aromas place high in consumer assays, and there are more fruits listed than any other aroma descriptors.

The Floral-Fruity Group predominantly circumscribes highly volatile monoterpenes often called “loud” by cannabis connoisseurs. The major monoterpene limonene is second only to myrcene in abundance, and in certain hemp and hop cultivars, limonene content can exceed myrcene. Limonene has a sweet, fresh-fruity, citrus-peel aroma expressing rosemary, juniper and peppermint highlights. Linalool has a sweet, floral aroma with green-woody, orange, blueberry and candied spice notes, and an orange and lemon, floral, waxy and woody flavor. Terpineol usually occurs as a mixture of four isomers with alpha-terpineol as the major constituent, contributing its floral, lilac, pine, apple, lime and orange aroma. Ocimene has a floral, tropical, green, citrus fragrance and flavor with woody, vegetable nuances. Ocimene also shares characteristics with the Green-Herbal Group; and carene with its pungent, sweet citrus aroma and woodsy hints of pine and cedar overlaps with Woody-Spicy.

The minor monoterpenes geraniol, citronellol, nerol, cymene and methyl-heptenone also contribute to the floral and fruity aromas so popular among sinsemilla enthusiasts. Geraniol has a sweet, floral and fruity aroma with rose, citrus and citronella overtones, and a floral, waxy and perfume-like flavor with fruity, rose and peach nuances. Nerol is an isomer of geraniol with a similar fresh, sweet rose aroma also found in hop essential oils. Citronellol projects a floral, waxy leather, rose bud and citrus aroma with green, fatty, turpentine-like nuances, and a green, fruity flavor with overtones of apple, orange, lime and lilac.

Cymene presents a harsh, spicy, musty, woody, tangy, turpentine-like, fresh citrus aroma with carrot overtones, oxidized citrusy lemon notes, and spicy nuances reminiscent of cumin, oregano and cilantro, and has a turpentine-like rancid taste with slightly woody, oxidized citrus notes and spicy green pepper and oregano nuances. Cymene also shares commonalities with the Woody-Spicy Group. Methyl-heptenone has a sweet, pungent, earthy, green, musty, citrus, lemongrass and apple flavor, with slight creamy cheese and banana nuances.

Some minor sesquiterpenes also present pronounced floral and fruity aromas. Valencene is characterized as sweet, oily and dry, with fresh, green and woody nuances and a strong grapefruit and orange flavor. Nerolidol (not to be confused with nerol) has a mild, delicate, sweet floral aroma with citrus-like green apple, rose and woody waxy nuances, and a woody, green, floral flavor with hints of citrus and melon. Bisabolol offers a sweet, floral, tangy, fresh and clean aroma with peppery citrus notes.

Gassy Group

Gassy aromas constitute another popular fragrance and flavor group, and, like the Dank and Green-Herbal groups, the Gassy Group is populated by only minor terpenes. Menthol, camphor and piperitenone contribute to the solvent and fuel aromas of some gassy cultivars. Refreshing menthol is cooling and minty, and camphor carries a characteristic pungent medicinal aroma, while piperitenone shares solvent-like characteristics in its herbal camphor and peppermint aroma. All terpenes are aromatic hydrocarbons and, at sufficient concentrations, many outside of the Gassy Group can be characterized as gassy or solvent-like.

Marketing Aromas

Although each cultivar produces a range of terpenes, their aromas blend to produce the scent characteristic of that cultivar and the Cannabis Fragrance & Flavor Group to which it belongs. How can businesses employ Cannabis Fragrance & Flavor Groups to their best advantage? From a marketing perspective, it is valuable to associate a cultivar with a Cannabis Fragrance & Flavor Group to more easily and effectively communicate with potential customers.

Aromas do not simply add to the pleasure of a delicious smoke, the terpenes responsible for those fragrances also have potentially powerful cerebral and corporeal outcomes.

Cannabis Fragrance & Flavor Groups can raise consumer expectations and spark curiosity beyond simple THC percentage, a mere number somewhat related to potency and only vaguely responsible for the many subtle and desirable effects of cannabis use. Terpenes modify the effects produced by the cannabinoids in many ways and are seductively delicious as well. Terpene diversity underlies cultivar diversity. Aroma is the brand!

Cannabis Fragrance & Flavor Groups can awaken consumers to the variety of cultivars on the market and pique their interest in discovering and enjoying them. Customers can’t decide to try something different if they don’t know it exists.

Robert C. Clarke is a freelance writer, photographer, ethnobotanist, plant breeder, textile collector and co-founder of BioAgronomics Group Consultants, specializing in smoothing the transition to a wholly legal and normalized cannabis market.

Mojave Richmond is the developer of many award-winning varieties such as S.A.G.E., which served as a springboard for creating many notable cultivars. Richmond is a founding member of the international consulting company BioAgronomics Group.