The number on the jar is doing less than you think
Walk into any menu and the flower is sorted by one figure: total THC. It is the easiest number to compare, so it became the number everyone compares. It is also close to useless as a prediction of how a given strain will actually feel.
THC percentage tells you how much of one molecule is present by weight. It does not tell you how quickly it reaches you, how long it holds, whether it leaves you talkative or flattened, or whether you will enjoy it. Two jars at the same 28% can produce experiences that have almost nothing in common.
What the percentage actually measures
Cannabis does not contain much THC while it is alive. It contains THCA, an acid that converts to THC when heated. Labs report both, and the figure printed as "total THC" is a calculation: the THCA multiplied by 0.877, plus whatever delta-9 THC is already present.
That 0.877 is the mass lost when the acid group breaks off. It assumes complete conversion, which a lighter never quite achieves. The number on the label is therefore a ceiling — the most THC that could reach you if combustion were perfect, not the amount that does.
Terpenes are the part you can smell
Terpenes are the aromatic compounds responsible for why one jar smells of diesel and another of lemon peel. They are not unique to cannabis: limonene is what makes citrus rind smell like citrus rind, pinene is what a pine forest smells like, and linalool is most of lavender.
Total terpene content usually lands between 1% and 4% by weight. Anything above 2% is considered aromatic, and growers who chase potency alone often produce flower that tests high and smells of almost nothing.
The claim that specific terpenes reliably steer a high in a specific direction — the so-called entourage effect — is popular and only partly supported. There is good evidence that terpenes shape aroma and flavour, and reasonable evidence they modulate the experience. There is not good evidence for the confident charts that assign each terpene a mood. Treat those as folklore with a grain of truth in them.
Indica and sativa describe plants, not effects
The indica/sativa split originally described plant morphology — short and broad-leaved against tall and narrow. After decades of hybridisation, almost everything commercially available is a hybrid, and the label on the shelf reflects marketing lineage more than botany.
The words remain useful as rough shorthand for what a seller expects you to feel, which is genuinely informative, because sellers pick the label based on how the strain has landed for customers. Just do not mistake it for a chemical fact about the jar.
A better way to choose
Read the terpene section of the certificate of analysis before the potency section. If the menu does not publish one, that is itself information.
Buy small quantities of several things rather than a large quantity of one. An eighth you dislike is a more expensive mistake than two grams you learn from.
Keep a note of what you actually enjoyed — strain, grower, harvest date, dominant terpene. Within a few purchases you will have a better predictor than any number on a jar.
And treat a very high percentage as a reason for a smaller first dose, not a better product.