Professor invents red hot chilli meter

Professor Richard Compton of the University of Oxford has been experimenting with the world's hottest pepper sauces. Given their fiery pungency, he's careful not to taste undiluted. Instead, thanks to carbon nanotubes and adsorptive stripping voltammetry, he's developed an objective method to measure that intense heat.

The heat level in chillies is usually measured using the Scoville organoleptic (sensory) test. Developed by American scientist Wilbur Scoville in 1912, it uses a series of dilutions with taste volunteers - a mild chilli pepper has a rating of 2,500-8,000 Scoville units. How we feel the "heat" is also well understood: compounds known as capsaicinoids trigger chemoreceptor nerve endings in the skin.

Compton's academic expertise lies in electrochemistry and sensors. Why does he use carbon nanotubes for sensing chilli heat? "It's as trivial as having a huge surface area for conductivity," says Compton. A carbon nanotube is an arrangement of carbon atoms in a hollow tube 50,000 times thinner than a human hair. The multi-walled nanotubes used by Compton are like tubes within tubes to give the right surface area.