Ask anyone to describe a modern American cultivar and the word that comes up is "gassy". Fuel, diesel, petrol, that sharp chemical edge sitting underneath the sweetness in something like Gelato or Runtz.
Here's the thing that catches people out: that smell is mostly not terpenes. It's a different class of molecule entirely, and understanding why matters if you've ever wondered why a terpene-only reproduction of a gassy strain gets the sweetness right and still somehow misses.
What thiols are
Thiols, also called mercaptans, are sulphur-containing aromatic compounds. They occur naturally across the plant kingdom, in fruits, flowers, alliums and hemp.
The defining characteristic of a thiol is potency. These molecules are detectable by the human nose at concentrations measured in parts per trillion, orders of magnitude lower than terpenes. A quantity too small to register on most analytical equipment can dominate the aroma of an entire batch.
You have almost certainly encountered them deliberately. Natural gas is odourless, so gas utilities add a thiol to it specifically so that leaks can be smelled. That characteristic gas smell is a mercaptan. The same chemistry gives grapefruit its bitter edge, cat urine its pungency, and certain cannabis cultivars their fuel note.
In aroma terms thiols read as gassy, diesel, skunky, sulphurous or pungent. They're the reason "skunk" became a name for a type of cannabis in the first place.
What esters are
Esters are the other half of the equation, and they pull in the opposite direction. They contribute fruity, sweet, rounded notes, and they're found throughout nature in fruits, flowers and herbs.
If thiols provide the sharp edge, esters provide the sweetness and body that makes it palatable rather than simply acrid. The interplay between the two is what gives dessert-and-fuel cultivars their characteristic tension: sweet on top, gas underneath.
Why terpenes alone can't do it
A conventional terpene profile reconstructs a cultivar's aroma using isolated terpenes blended to match the ratios found in the real plant. For most strains that works extremely well.
But if a significant part of a cultivar's identity comes from non-terpene molecules present at parts-per-trillion, no amount of terpene blending will reproduce it. You can get the citrus, the earth, the pepper and the sweetness exactly right and the result will still smell like a good approximation rather than the real thing, because the component doing the distinctive work isn't in the blend at all.
This is the gap that the newer generation of formulations set out to close.
Deep Terpene Profiles and the Gassy Line
Cali Terpenes' Deep Terpene Profiles is a separate category built to address exactly this. The approach starts with a conventional terpene profile as the backbone, then adds complementary aromatic fractions, specifically esters and thiols, extracted from fresh hemp plants.
The important distinction, and it's one the manufacturer is explicit about:
- These are not artificial flavourings
- They are not synthetic aromas added to imitate a smell
- They are natural aromatic molecules obtained by extracting volatile compounds from living hemp plants
The terpene profile still defines the identity of the formulation. The added aromatic base deepens and expands it, providing the background layer that a terpene-only blend can't reach.
The first line in the category is the Gassy Line, built around that fuel character. Profiles include Gaskittlez, Gelato Gas, Runtz Gas, Amnesia Gas, Cookies Gas, Dosi Gas, Gas Mintz, Glue Gas, L.A. Kush Gas, OG Gas and Wedding Gas.
Working with them
Deep profiles behave like standard terpene profiles in terms of dilution, the same 1–3% range applies, but there are two practical differences worth knowing.
They are more assertive. The thiol component is doing a lot with very little. Start at the bottom of the range rather than the middle, and give the mix a full day before judging it.
The gas note develops. The background layer tends to emerge and settle over time rather than announcing itself immediately. A blend that seems subtle an hour after mixing may read very differently the following day, which is another argument for not correcting a mix too early.
Our dosage and dilution guide covers the general mixing principles, and they all apply here.
Frequently asked questions
What does "gassy" mean in cannabis?
A sharp fuel, diesel or petrol-like aroma note, characteristic of many modern cultivars with American lineage. It comes mainly from thiols rather than terpenes.
What are thiols?
Sulphur-containing aromatic compounds, also called mercaptans, detectable at extremely low concentrations. They're what's added to natural gas to make leaks smellable, and they occur naturally in hemp, grapefruit and many other plants.
Are thiols natural or synthetic?
Thiols occur naturally across the plant kingdom. In Deep Terpene Profiles they're obtained by aromatic extraction from fresh hemp plants rather than synthesised.
Do Deep Terpene Profiles contain cannabinoids?
No. Like standard terpene profiles they contain no CBD, THC or other cannabinoids. They're aroma formulations.
What's the difference between a Deep profile and a standard one?
A standard profile is terpenes only. A Deep profile uses the same terpene backbone plus additional natural aromatic fractions, esters and thiols, that create background layers terpenes can't produce on their own.
Why does my terpene blend not smell like the real strain?
If the strain has a strong gassy or skunky character, that component is likely thiol-derived and won't be present in a terpene-only profile. It's exactly the gap the Deep category exists to fill.
Is the gassy smell the same as skunk?
They're related. Both come from sulphur compounds. "Skunky" and "gassy" describe different points on the same broad aromatic family.
Browse the terpenes range, or read our guide to the main cannabis terpenes for the conventional side of the picture.
18+ only. Terpene and Deep Terpene profiles are concentrated aroma ingredients containing no cannabinoids, for use in appropriately diluted formulations. Consult the safety data sheet before use. Nothing in this article is a health or medical claim.