Scoville Heat Units · 0 → 2,693,000
Sixteen peppers from around the world, in order of heat. Each one measured in Scoville Heat Units — how far its extract must be diluted before a human tongue stops registering the burn. Scroll to climb the scale.
The unit
1 part chilli extract, diluted into N parts sugar water, until the burn can no longer be tasted.
That N is the Scoville rating.
It is a dilution factor, not an amount. A jalapeño at 5,000 SHU is not carrying five thousand of anything — it means its extract had to be thinned five thousand times over before the heat vanished. Which is why the scale runs into the millions, and why a bell pepper sits at zero rather than at one.
Wilbur Scoville, a pharmacist at the Parke-Davis drug company, needed to compare pepper batches for a heat-producing muscle rub. He steeped dried pods in alcohol, diluted the extract in sweetened water, and handed it to five tasters. He kept diluting until three of the five could no longer feel anything. The dilution that finally silenced the burn became the pepper's number.
Nobody runs the taste panel any more — palates fatigue, tolerance varies, and two labs could disagree by half. Today's figures come from high-performance liquid chromatography, which measures the actual capsaicinoids, mostly capsaicin and dihydrocapsaicin, in parts per million. That result is multiplied by roughly 16 to convert it back into Scoville's units, because his is the scale everyone knows.
It measures concentration, not experience. It says nothing about how fast the heat arrives, how long it stays, or where in the mouth it lands — the first things anyone actually notices between a bird's eye and a habanero. And one figure hides enormous spread: pods off a single plant vary severalfold with sun, water stress and ripeness.
Pure capsaicin sits at 16,000,000 SHU — the top of the scale by definition. Everything below is that same molecule, diluted by the fruit that made it.
Sources · W. L. Scoville, “Note on Capsicums”, Journal of the American Pharmaceutical Association 1(5), 1912, pp. 453–454 · American Spice Trade Association Analytical Method 21.3, capsaicinoids by HPLC · Guinness World Records certifications for the record-holding cultivars.
All sixteen
Every pod above, grown by the same function from the same anchor and drawn to the same scale. The sizes are the pods' real proportions, compressed so a 3 cm bird's eye stays legible beside a 12 cm poblano. Pick one to go back to it.