Preamble: How Does the Human Sense of Smell Work?
The sense of smell is one of the most fascinating and complex senses in our body. It relies on an interaction between volatile molecules (odors) and a highly specialized sensory organ: the olfactory organ, located in the nasal cavity.
The odor perception process
- Inhalation of odorant molecules: When you smell a cannabis flower, odorant molecules enter your nose. They reach the olfactory epithelium, an area covered in specialized cells.
- Activation of olfactory receptors: These molecules bind to specific receptors on the cilia of olfactory neurons. Each receptor is sensitive to certain types of molecules.
- Transmission to the brain: The signals are sent to the olfactory bulb, which interprets them and links them to memories or emotions.
Why are some odors difficult to identify?
- Complexity of mixtures: Cannabis flowers release hundreds of different molecules simultaneously, which creates complex aromas. Our brain may have difficulty isolating each component.
- Habituation: If you smell several flowers in succession, your nose becomes "fatigued": this is a phenomenon of olfactory adaptation where receptors become less sensitive to certain molecules.
- Odor contrast: When aromas overlap, our perception can be distorted.
The coffee trick
Smelling coffee between two olfactory analyses can "reset" your nose (its effectiveness remains modest, however). Coffee beans temporarily neutralize habituation, making your receptors more sensitive.
Cannabis Odors: A Fascinating Chemical Journey
The varied and complex aromas of cannabis are the result of a multitude of volatile molecules present in the flowers. These molecules belong to different chemical families, which, together, create the unique olfactory signature of each strain.
The Molecule Families Responsible for Cannabis Odors
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Terpenes (read our article on terpenes: molecules with super powers)
- Terpenes are primarily responsible for cannabis aromas. These aromatic hydrocarbons are produced by trichomes and give cannabis its fruity, woody, floral, or spicy notes.
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Examples in cannabis:
- Myrcene (earthy, musky)
- Limonene (citrusy)
- Pinene (pine, resinous)
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Other plants containing terpenes:
- Myrcene is found in mango.
- Limonene is found in citrus fruits like lemon and orange.
- Pinene is typical of conifers.
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Flavonoids
- These molecules, although less fragrant than terpenes, provide floral and fruity nuances. They also play a role in the color of the flowers.
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Examples in cannabis:
- Apigenin (sweet, floral)
- Cannaflavin A (herbaceous notes)
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Other plants containing flavonoids:
- Apigenin is found in chamomile.
- Anthocyanins (a sub-family of flavonoids) are found in blueberries.
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Sulfur compounds
- These molecules, although rarer, provide powerful aromas reminiscent of onion, cheese, or diesel.
- Example in cannabis: Thiols, responsible for "skunk" odors.
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Other plants containing sulfur compounds:
- Garlic and onion are rich in thiols and sulfur compounds.
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Esters
- Esters are the origin of sweet, fruity, or even creamy notes. They form during the curing of the flowers.
- Example in cannabis: Bornyl acetate (mentholated, sweet).
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Other plants containing esters:
- Tropical fruits, like pineapple or banana, contain esters in abundance.
An Example of the Benefits of a Molecule: Limonene
Limonene, a terpene with a fresh, lemony scent, is present in cannabis, but also in citrus fruits (lemon, orange).
Potential benefits of limonene:
- Anti-stress and anxiolytic effects: it works by modulating certain neurotransmitters in the brain.
- Antibacterial and anti-inflammatory properties: useful for soothing inflammation and reducing infections.
- Positive effect on the digestive system: it helps relieve heartburn and acid reflux.
Cannabis aromas are not there by chance: they reflect a natural alchemy that links the plant to other plant species. Each molecule tells a unique chemical story, sometimes shared with fruits, flowers, or even trees. Beyond the aromas they offer, these molecules can also contribute benefits for the body and mind.
More "Surprising" Cannabis Aromas and Their Chemical Origins
1. The smell of Diesel
This powerful and characteristic smell, present in strains like Sour Diesel, is due mainly to terpenes and sulfur compounds.
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Responsible terpenes:
- Myrcene: earthy and musky, it forms a base.
- Limonene: provides a "solvent" citrus note.
- Caryophyllene: peppery, spicy, and slightly petroleum-like.
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Specific chemical compounds:
- Thiols: These sulfur molecules are known for evoking strong odors like gas or petroleum. They are similar to those found in certain fuels or skunk spray.
The benefits of Myrcene:
Myrcene, the primary terpene in cannabis, promotes muscle relaxation and acts as a natural sedative, often used to improve sleep.
Anecdote: Ancient peoples of South America consumed mangoes rich in myrcene before smoking cannabis, believing it intensified the effects by improving cannabinoid absorption. 🌿🥭
2. The smell of Cheese
"Cheese" strains, like the iconic ROYAL CHEESE, give off a smell reminiscent of fermented cheeses.
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Responsible terpenes:
- Caryophyllene and humulene: provide earthy and spicy notes that evoke mold.
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Specific molecules:
- Carboxylic acids: These compounds contribute to the odors of fermentation and dairy products.
- Ethyl butyrate: Responsible for creamy and slightly rancid nuances.
The benefits of Humulene:
Humulene, a terpene with earthy and spicy notes, is known for its anti-inflammatory and natural appetite-suppressant properties.
Anecdote: It is also present in hops used to brew beer, which explains the aromatic similarities between certain cannabis strains and a well-hopped IPA. 🌿🍺
3. The smell of vomit
Certain poorly preserved flowers or those resulting from specific genetics may give off an unpleasant smell evoking vomit. This scent, although rare, is often linked to sulfur molecules and degradation products.
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Chemical culprits:
- Isovaleric acids: These compounds form in humid or poorly ventilated environments. They are reminiscent of strong body odors.
- Volatile amines: Resulting from the decomposition of certain organic compounds.
4. The smell of toasted bread
Toasted or roasted notes often come from drying and curing processes.
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Responsible terpenes:
- Humulene: provides earthy and malty notes.
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Specific molecules:
- Furans and pyrazines: Released during the degradation of sugars and proteins in the trichomes.
Furans and pyrazines are aromatic compounds responsible for the toasted, nutty, and caramelized notes in cannabis. These molecules often form during curing or aging.
Anecdote: Pyrazines are also present in roasted coffee and dark chocolate, explaining the aromatic similarities between these products and certain cannabis strains with hazelnut or toasted bread accents. 🌿☕🍫
5. The smell of cream
Sweet, milky aromas, sometimes reminiscent of cream, are less common but sought after for their originality. These notes are typical of strains rich in esters.
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Responsible esters:
- Ethyl lactate: provides sweet and creamy nuances.
- Ethyl butyrate: Reminiscent of cream and butter.
The More "Classic" Cannabis Aromas and Their Chemical Origins
1. The Herbaceous Notes of cannabis
These fresh aromas are reminiscent of cut grass, leaves, or green plants.
Responsible terpenes:
- Myrcene: Contributes to earthy and musky nuances, often perceived as herbaceous.
- Caryophyllene: Adds a slightly peppery and vegetal touch.
- Humulene: Adds earthy aromas, sometimes evoking hops or dried herbs.
Caryophyllene, a spicy and peppery terpene, stands out for its unique ability to interact with the endocannabinoid system, offering anti-inflammatory and analgesic properties.
Fun fact: This terpene is also found in black pepper, and chewing peppercorns is a well-known trick for mitigating the effects of a cannabis "bad trip." 🌿🌶️
Specific molecules:
- Hexenol: Responsible for the scent of freshly cut grass.
- Phytol: Releases deep herbaceous notes, often associated with degraded chlorophyll.
Phytol, a compound found in cannabis trichomes, is recognized for its relaxing properties and antioxidant effects.
Fun fact: This terpene is also a precursor to vitamin E, and it is found in green tea, where it contributes to its herbaceous aromas and soothing benefits. 🌿🍵
This compound, derived from the breakdown of chlorophyll, is also used in perfumery and food supplements to promote sleep and reduce stress. 🌿🌼
2. The Spicy Notes of cannabis
The spicy aromas of cannabis are reminiscent of spices such as black pepper, cinnamon, or cloves. These complex scents are found in varieties like Aurora.
Responsible terpenes:
- Caryophyllene: Peppery, woody, and slightly pungent. It is one of the few terpenes that interacts with the endocannabinoid system.
- Humulene: Adds a spicy wood nuance, sometimes reminiscent of ginger.
- Sabinene: Present in smaller quantities, it imparts notes of pepper and nutmeg.
Sabinene, a terpene with peppery, woody, and slightly lemony aromas, is recognized for its antimicrobial and anti-inflammatory properties.
Fun fact: Sabinene is found in juniper berries, used to flavor gin, which explains the aromatic similarities between this spirit and certain cannabis varieties. 🌿🍸
Specific molecules:
- Eugenol: Provides aromas close to clove.
- Linalyl acetate: Contributes a spicy sweetness evoking lavender or musk.
Eugenol, a terpene with warm aromas of clove and cinnamon, is known for its analgesic, antiseptic, and anti-inflammatory properties.
Fun fact: Used for centuries in traditional medicine, particularly to relieve toothaches, eugenol is also present in basil and bay leaves, adding an aromatic touch to Mediterranean dishes. 🌿🦷🍃
3. The Lemony Notes of cannabis
Citrus aromas, evoking lemon, lime, or even tangerine, are vibrant and invigorating. They are typical of varieties like the Lemon Haze or Lemon Ice.
Responsible terpenes:
- Limonene: Main contributor of lemony notes. It is also associated with a sense of freshness and lightness.
- Terpinolene: Complex, with hints of citrus and flowers.
- Beta-Phellandrene: Offers aromas reminiscent of lime and grapefruit.
Fun fact: Beta-phellandrene is also found in eucalyptus and parsley, where it contributes to their invigorating aromas, often associated with refreshing and soothing effects on the respiratory tract. 🌿🍋🌱
Specific molecules:
- Citral: A combination of geranial and neral, which gives a powerful lemony note.
- Linalool: Adds sweet, slightly lemony, and floral nuances.
Citral, a compound with powerful lemon and lime aromas, is valued for its antimicrobial, antifungal, and relaxing properties.
Fun fact: Found in lemongrass and lemon peel, citral is widely used in aromatherapy to reduce stress and in cooking to flavor exotic dishes with a fresh and tangy touch. 🌿🍋✨
4. The Red Fruit notes of cannabis
These sweet and juicy aromas, characteristic of varieties like Holy Bull or Hessdalen, are very enticing.
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Responsible terpenes:
- Nerolidol: raspberry and strawberry notes, it forms a base.
- Limonene: provides lemony freshness.
- Pinene: confers a touch of woody freshness.
Pinene, a terpene with fresh pine and resin aromas, is known for its anti-inflammatory and bronchodilator properties, and for improving memory.
Fun fact: It is also found in pine needles and rosemary, and steam baths based on these plants have long been used to soothe the respiratory tract and promote relaxation. 🌿🌲✨
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Specific molecules:
- Methyl anthranilate: Provides grape and berry notes.
- Gamma-decalactone: Evokes peach and apricot.
Methyl anthranilate, a compound with sweet grape and berry aromas, is recognized for its soothing and slightly sedative properties.
Fun fact: It is also found in orange blossoms and Concord grapes, where it contributes to their sweet and floral notes, and it is used in perfumery to create gourmet and comforting fragrances. 🌿🍇🌸
How to refine your sense of smell for cannabis?
- Take your time: Inhale slowly, focus on the primary aromas (the most obvious ones), then look for the nuances.
- Alternate with neutral scents: Coffee is an excellent option, but a clean cloth can also do the trick.
- Take breaks: Do not smell more than three flowers in a row without a break.
- Practice: Familiarize yourself with individual terpenes to better recognize them.
The aromas of cannabis are a true invitation to an olfactory journey. By understanding the chemical and biological mechanisms underlying them, you will enrich your experience and be better equipped to identify every subtlety. Whether it's a scent of diesel, cheese, or red fruits, each variety tells a unique chemical story! 🌿