Two cannabis flowers can have near-identical THC numbers on the label and feel completely different. The label is not telling you the whole story. What is missing is the terpenes, and once you understand them you understand why the same plant can behave in so many different ways.
What a terpene is
Terpenes are aromatic compounds produced by a huge range of plants. They are what you smell when you crush a pine needle, zest a lemon, or walk past a lavender bush. Plants make them for their own reasons: to deter insects, to attract pollinators, to protect against heat and UV.
Cannabis produces a lot of them, in the same sticky glandular trichomes that produce cannabinoids. Well over a hundred have been identified in the plant. A handful dominate any given flower, and that combination is what your nose is reading.
Why different cannabis does different things
Our founder Abe Gray explains the mechanism better than we can.
The point he makes is the one people miss when they say cannabis can do a lot of different things. It is not one substance doing many things. It is many different types of cannabis, and you need the right type, delivered the right way, at the right time. The complexity is enormous: by his reckoning there are over 64 million possible combinations in the plant.
Underneath that sits your own body. We have an endocannabinoid system with receptors in different places doing different jobs. CB1 receptors are concentrated in the brain and central nervous system, and that is where THC acts, which is why THC is psychoactive. CB2 receptors sit largely in the immune system and the gut, away from the brain, which is why activity there does not produce a high.
CBD is the interesting one. It barely binds either receptor directly, working instead through other pathways and by changing how other compounds behave at CB1. Either way, the practical point stands: different compounds act at different places, which is why different combinations feel different.
The entourage effect:
Cannabinoids and terpenes work together, and the combination produces effects that no single isolated compound produces on its own. That is the whole reason a whole flower behaves differently from an equivalent dose of isolated THC.
Indica and sativa: it was the terpenes all along
The indica and sativa labels describe plant shape and breeding history, not chemistry, and modern cultivars are so crossed that the names tell you almost nothing about the plant itself.
But the effects people are describing when they use those words are real. They have just been attributing them to the wrong thing. What actually modifies the character of a THC effect is the terpene profile.
Broadly, and with all the individual variation you would expect:
- Piney and lemony profiles, dominated by pinene and limonene, tend toward the brighter, more uplifting end of things.
- Lavender and thyme profiles, dominated by linalool and related compounds, tend toward the more sedative end.
Which is why your nose is a better guide than the label. If you have used cannabis for any length of time you already know this: you can smell the difference between a flower that will pick you up and one that will put you down.
The ones you will smell most often
Myrcene is the most common terpene in cannabis. Earthy, musky, a bit like ripe mango or cloves. Also found in hops, which is part of why some cannabis smells faintly like beer.
Limonene is citrus: lemon, orange peel, grapefruit. The same compound that makes citrus rind smell the way it does.
Pinene is exactly what it sounds like. Pine needles, rosemary, fresh forest. It comes in two forms, alpha and beta, and it is one of the most abundant terpenes in the natural world.
Caryophyllene is peppery and spicy, the same compound that gives black pepper its bite. It is unusual because it binds directly to the CB2 receptor, which makes it a terpene that behaves a bit like a cannabinoid.
Linalool is floral and soft, the dominant note in lavender.
Terpinolene is harder to pin down: fresh, herbal, slightly fruity, a bit like apples and nutmeg.
The famous diesel and fuel smells are not a single terpene. They come from combinations, and from a separate family of sulphur compounds only identified in cannabis relatively recently. That is why nobody could ever find the diesel terpene: it was never a terpene.
What actually dictates quality
This follows directly from the above, and it is the most useful thing on this page if you are choosing between products.
Preservation of the trichomes is the key thing. The trichome is a delicate little bubble sitting on the surface of the flower, and it holds the terpenes. Pop it and the terpenes simply evaporate. Everything that happens to a flower between harvest and your vaporiser either preserves those trichomes or damages them.
Which means the things worth caring about are:
- Freshness. It is a botanical product, not a pharmaceutical tablet. Fresher is better.
- How far it has travelled. Less handling and less distance means less trichome damage. Closer to home is generally better.
- Whether it has been through harsh sterilisation. Processes like irradiation do things to a delicate aromatic product that are not reflected anywhere on the label.
- Whether you can still smell it. This is the test anyone can apply. Strong aroma means the trichomes are intact and the terpenes are still there. A flower that smells of very little has lost something, whatever the THC number says.
Potency matters to a lot of people, and the THC percentage is the number everyone looks at. But it is one number describing one compound, and it tells you nothing about the terpene content, which is largely unreported. Two flowers at the same THC will not perform the same if one has been kept intact and the other has not.
Why this decides your vaporiser temperature
Terpenes evaporate at much lower temperatures than cannabinoids, and many begin breaking down well below the point where THC boils off.
So if you run your vaporiser hot, you lose the terpenes first. Your first draw at a low temperature carries most of the aroma and most of the character. Run it high and you get a fuller, heavier vapour with much less of what makes that particular flower itself.
This is one of the strongest arguments for vaporising rather than burning. Combustion destroys terpenes completely, along with a good proportion of everything else you paid for. A vaporiser with real temperature control lets you choose what you are extracting: start low for the aromatics, work up through the session for the heavier compounds.
If your device has one fixed temperature, that is the case for upgrading. Not more vapour, more control over what is in it. Every vaporiser we stock has adjustable temperature, and you can try them all in person.
Storage matters for the same reason. How you keep your flower decides how much of the terpene content survives to the point where you use it.
Come and smell them
Descriptions of smells are famously useless. Reading that something is earthy and musky tells you almost nothing until you have it under your nose.
The Cannabis Science area at the museum has terpene samples you can smell, alongside the anatomy of the plant and how the trichomes work, and you can see and smell the medicinal cannabis products currently available to patients in New Zealand. It is the fastest way to understand any of this, and it is free. Plan your visit.
General information only, not medical advice. Individual responses vary considerably. What you are prescribed is a decision for your doctor.
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