What is a Scoville unit?
The Scoville scale measures the concentration of capsaicin, the compound that makes chillies hot. It was originally a dilution test — sugar water against the chilli extract until the heat was no longer detectable. These days it is measured by liquid chromatography, but the headline number stuck.
Scoville
NaN SHU
010K100K1M2.2M
The Ghost Pepper sits at just over a million SHU, which sounds dramatic until you meet a Carolina Reaper.
Why the number lies
A single number cannot tell you how the heat lands on your tongue. A Scotch Bonnet and a Cayenne can sit at similar SHU values and feel completely different — one is fruity and rounded, the other is sharp and immediate.