Guide
The Scoville Scale, Explained
How Scoville Heat Units (SHU) measure chilli heat — and where the peppers behind your favourite hot sauces actually land.
What is the Scoville scale?
The Scoville scale is a measurement of the pungency (spicy heat) of chilli peppers and other spicy foods. It was created in 1912 by American pharmacist Wilbur Scoville, and the unit is called the Scoville Heat Unit (SHU).
In short: the more capsaicin a pepper contains, the higher its SHU value. A bell pepper sits at 0 SHU. A Carolina Reaper can exceed 2,000,000 SHU.
How are Scoville Heat Units calculated?
Scoville's original method — the Scoville Organoleptic Test — dissolved a dried pepper extract in sugar water and asked trained tasters how much dilution was needed before they could no longer detect any heat. If it took 10,000 parts of sugar water to neutralise one part of extract, the pepper scored 10,000 SHU.
Modern labs use High-Performance Liquid Chromatography (HPLC) to measure capsaicinoids directly in parts per million, then convert that value to SHU. It's faster, repeatable, and removes the guesswork of human tasters — but the unit name stuck.
Chilli SHU values, from mild to extreme
Heat varies a lot even within a single pepper variety — soil, sunlight, and ripeness all matter. These ranges are typical:
| Pepper | Scoville Heat Units | Notes |
|---|---|---|
| Bell pepper | 0 | No measurable capsaicin. |
| Poblano | 1,000–2,000 | Mild warmth, used in mole. |
| Jalapeño | 2,500–8,000 | The everyday reference point for 'a little kick'. |
| Serrano | 10,000–23,000 | Bright, sharp heat. |
| Cayenne | 30,000–50,000 | Backbone of most red hot sauces. |
| Thai bird's eye | 50,000–100,000 | Quick, clean burn. |
| Habanero | 100,000–350,000 | Fruity, lingering, serious heat. |
| Scotch bonnet | 100,000–350,000 | Caribbean cousin of the habanero. |
| Ghost pepper (Bhut Jolokia) | ~1,000,000 | Slow-building, brutal finish. |
| Trinidad Scorpion | ~1,400,000 | One of the hottest naturally grown chillies. |
| Carolina Reaper | 1,500,000–2,200,000 | Former world record holder; extreme territory. |
| Pepper X | ~2,700,000 | Current Guinness world record (2023). |
| Pure capsaicin | 16,000,000 | The reference ceiling of the scale. |
From Jalapeño to Carolina Reaper
The jump from a Jalapeño (~5,000 SHU) to a Carolina Reaper (~1,800,000 SHU) isn't twice as hot, or ten times — it's roughly 360× hotter. That's why heat tiers matter more than raw numbers when you're scanning a collection: anything above ~100,000 SHU is in a fundamentally different league.
The heat tiers we use across this site map roughly to:
- Extreme — 500,000 SHU and above
- Very Hot — 100,000–500,000 SHU
- Hot — 50,000–100,000 SHU
- Medium-Hot — 15,000–50,000 SHU
- Medium — 5,000–15,000 SHU
- Mild — under 5,000 SHU
- Unspecified — pepper type unknown, heat level not estimated
The hottest sauces in this collection
Here are the top five sauces ranked by SHU — all firmly in extreme territory:
- 1.Carolina Reaper — Gindos1,569,300 SHU
- 2.Green Reaper — Gindos1,569,300 SHU
- 3.Marshmallow Reaper Peri Peri — Gindos1,569,300 SHU
- 4.Sweet Reaper — Gindos1,569,300 SHU
- 5.Sweet Reaper — Papa Caps1,569,300 SHU
Want to see all 500+ sauces ranked head-to-head? Browse the full heat ranking →
Frequently asked
What does SHU stand for?
Scoville Heat Unit — the unit used to measure the spicy heat of chilli peppers.
What is the hottest pepper in the world?
As of 2023, Pepper X holds the Guinness World Record at roughly 2.69 million SHU, surpassing the Carolina Reaper.
Is the Scoville scale accurate?
Modern HPLC testing is highly accurate for a given sample, but the same variety of pepper can vary widely depending on growing conditions — so published SHU values are usually ranges, not exact numbers.