SHU vs Capsaicin Content: What's the Difference
Capsaicin is the chemical compound that causes the burn; SHU is the scale that quantifies it. This comparison explains the relationship — and what SHU does and does not tell you about how a chilli will burn.
At a Glance
- Capsaicin
- Dominant capsaicinoid alkaloid
- SHU
- Concentration scale
- Conversion
- 1 ppm capsaicin ≈ 16 SHU
- Pure capsaicin
- ≈16 million SHU
The core difference
| Dimension | Capsaicin | SHU |
|---|---|---|
| What it is | The dominant member of the capsaicinoid family of alkaloids | A concentration scale for capsaicinoids, primarily capsaicin |
| Role | Triggers the burning sensation | Quantifies it — a chemical concentration, not a taste strength |
| Conversion | Roughly 1 ppm capsaicin ≈ 16 SHU | Pure capsaicin ≈ 16 million SHU |
| Limit | One compound among several | Averages several capsaicinoids — same SHU can burn differently |
Why the choice matters
"Capsaicin" is often used loosely to mean "heat", but it is really the dominant member of a small family of alkaloids. The full background is on the SHU explained page. Two chillies can share an identical SHU yet burn at a different speed, linger for a different time, and taste entirely different — because the number averages several capsaicinoids whose sensory character differs.
What SHU does not tell you
SHU is a chemical concentration, not a taste strength. Perceived heat is a sensory response that depends on the capsaicinoid mix, the food matrix and the individual taster — measured SHU and perceived heat correlate but are not interchangeable.
How to specify
Specify heat as an SHU window, not a single number — capsaicinoid content can shift ±40% within a single variety with growing conditions.
Heat and colour values are representative. Confirm your exact SHU window, ASTA, form and mesh when you inquire.
Frequently Asked Questions
What is the difference between SHU and capsaicin?
Capsaicin is the chemical compound — the dominant capsaicinoid that triggers the burn. SHU is the scale that measures capsaicinoid concentration: roughly 1 ppm capsaicin ≈ 16 SHU.
What is pure capsaicin in SHU?
Pure capsaicin registers around 16 million SHU — the conversion of roughly 1 ppm capsaicin ≈ 16 SHU.
Does the same SHU always burn the same?
No. Two chillies can share an identical SHU yet burn at a different speed and linger for a different time, because the number averages several capsaicinoids whose sensory character differs.