As more and more exotic and red hot chilli peppers are produced, here's a look at the science behind the heat.
The summer may be a washout so far weather-wise, but it’s been scorching at the growing number of chilli festivals around the UK.
Our own Andrew Webb recently witnessed the eye-watering sight of various participants at Bristol’s Grillstock Festival taking the chilli-eating challenge.
The heat of chillis is measured using something called the Scoville Scale. But how did this come about and how does it work?
In 1912, American pharmacist Wilbur Scoville created a test to measure the heat of chilli peppers. Scoville took the presence of capsaicin, a chemical compound found in the fruit, as his benchmark.
It's the capsaicin that makes our eyes water and our noses run when we eat a particularly potent chilli.
Scoville's experiments
The method Scoville devised took an extract of the pepper and diluted it in sugar water. His scale then measured the capsaicin content, essentially the heat, of the peppers based on the number of times it would have to be diluted to make that heat undetectable. The solution was then tested by a panel of five tasters.
So the sweet pepper, which has no heat, scores a 0. By contrast, the Jalapeno scores between 2,500 and 5,000. And pure capsaicin (don’t try this at home, folks) comes in at massive 15-16 million.
These measurements were named Scoville Heat Units (SHU).
There's a huge list of different chilli strengths here at the Chilli World website.
There were a few flaws with this method – notably the different tolerances and tastes of the testers.
Nowadays, chillis are measured using a technique called high performance liquid chromatography (HPLC), which measures their capacity to produce heat. These results are then converted into SHU.
The hottest stuff right now
The hottest chilli currently doing the rounds is the Moruga Scorpion from Trinidad, coming in at 1.2 million units on the Scoville scale.
Here's a video of an English lady giving one a try:
Previous record holders include the Infinity chilli, developed here in Grantham by grower Nick Woods, which came in at 1.17 million SHU.
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