The short answer is that they are organic compounds, or more specific resins. Resins that produce very, very strong smells. Terpenes only make up for approximately 1 percent of the weight of your bud, yet they are responsible for all of the delicious aroma’s that come off of it. The THC itself is odorless, so all the dank comes from the terpenes that the cannabis plant has produced in its trichomes.

A lot of plants produce terpenes and even some insects do. They are often used to fight off pests and predators but also fungal and bacterial infections. The essential oils of plants basically are terpenes as well and they are used in perfumes and aromatherapy a lot.

Terpenes in cannabis can be divided into two large groups: sesquiterpenes and monoterpenes.

• The monoterpenes are the smaller and more volatile ones, meaning that these are the ones that you smell when pinching a bud or a flower.

• The sesquiterpenes are the larger and heavier ones, being more locked in and not so volatile. The sesqui’s are also the ones that can only be experienced when smoked or vaped.

At least 120 different terpenes have been identified in Cannabis plants alone.

There's also an entourage effect. It means that the terpenes interact with the cannabinoids to deliver a different psychoactive result, depending on what cocktail of terpenes was present in the buds you were smoking. This basically accounts for the differences in experience when smoking for example White Widow or an Amnesia Haze.

Cannabis plants cannot (or do not) produce terpenes from their surrounding air or atmosphere, so good soil is important but not the only key to getting good smelling bud. UV light seems to stimulate the plant as well in producing terpenes so adding a UV spot or bulb could help your plants a lot in the production of even better smelling harvests.

Terpenes evaporate at temperatures above 27 degrees Celsius so keeping a low temperature would also help a lot. Anything that will stunt the growth of the plant will also cut back the production of terpenes, so the fewer problems the plant runs into the better the genetics of the particular strain will be expressed. Also making sure that the drying process isn’t rushed and buds are cured properly helps maintain the terpenes enclosed in your harvest and produce an even higher quality end product.

Below there's a list of the most encountered and more interesting terpenes found in cannabis and a description of the taste or scent and medical properties.

Myrcene

Myrcene tastes like hops, which is a close cousin to cannabis. It has an earthy, herbaceous and spicy taste or aroma. It helps with pain relief, inflammation and muscle relaxation. A strain with 0,5% myrcene or more is a sedative strain providing more of a couch lock effect, if it is below 0,5% myrcene it is a strain with an uplifting effect. Myrcene is mostly responsible for the psychoactive effect and causes the couch lock effect that is often associated with Indica strains. Myrcene is also found in mango’s and research has shown that eating a mango 45 minutes before use of cannabis gives a longer and more intense effect. White Widow has high levels of Myrcene.

Caryophyllene

Caryophyllene tastes like cloves and black pepper, a bit woody with spices. It has antibacterial, antiseptic and analgesic benefits. Caryophyllene is the only terpene able to interact with the body’s endocannabinoid system. It is also the most common terpene found in cannabis and supposedly is what drug dogs are trained to sniff out. Hash plants have the highest percentage Caryophyllene.

Pinene

Pinene tastes like pine trees but with sweet and sharp hints. It helps with respiratory problems like asthma because it works as a bronchodilator. Pinene also helps against inflammation and has the ability to actually make you more alert and help with memory retention. It is believed to be responsible for the ‘head high’ effect. Super Silver Haze and Bubba Kush have high levels of Pinene.

D-Limonene

Limonene tastes like citrus fruits, like lemons and oranges. It helps the immune system, works against tumors and modulates the psychoactive effects of cannabis. Limonene also helps with weight loss, works as an antidepressant and elevates the mood which makes it good for stress relief. Super Lemon Haze contains high levels of D-Limonene.

Humulene

Humulene has an earthy and woody taste, also reminding of hops. It is what gives beer it’s aroma. Humulene displays potent anti-inflammatory activity, acts as an appetite suppressant and has antibacterial properties. It is also found in sage, ginseng and Vietnamese coriander. Humulene has been used in traditional Chinese medicine for a long time.

Linalool

Linalool has a floral with spice aroma and is also found in mint, cinnamon and lavender. It has anti-inflammatory properties and helps modulate motor movement. It may even help against liver cancer and is a powerful insecticide. Humulene has sedative properties and is an effective anxiety and stress reliever. Amnesia Haze has high levels of Linalool.

Phellandrene

Phellandrene tastes and smells like peppermint and citrus fruits. It is found in plants of the Eucalyptus genus. Phellandrene has anti depressant effects and elevates the mood. It is what gives cannabis it’s minty flavour and is also good against digestive disorders. It is what oil of peppers and oil of dill are mainly comprised of.

Isoborneol

Isoborneol has a piney and woody aroma with hints of camphor and is found in mugwort species that have antiviral properties and has been used in traditional Chinese medicine extensively. Isoborneol is interesting because it proved to be a potent inhibitor of Herpes simplex type 1, better known as cold sores around the nose and mouth.

Terpineol

Terpineol tastes like pines and cloves and has antioxidant properties. It is often used in soaps and perfumes and is known to have relaxing effects. Terpineol is unique to the Jack Herer strain and it’s crossbreeds.