All Things Chilli


Spicy peppers are a hot topic of debate in the kitchen.  Some people choose to avoid them all together while others just can’t get enough of them. 

Unfortunately for me, too much chilli ends with a burning mouth, a runny nose and a large glass of cold milk.  So what makes chillies so hot?  And why can’t I handle them, while others can?  I decided to take a deep dive into all things chilli and find an answer to all my burning questions.

Why the burn?

Chillies naturally contain a compound called capsaicin which is responsible for the feeling of heat you get when you eat them.  The capsaicin is able to perfectly bind to a pain receptor (TRPV1) found in your mouth and nose, which sends a message to your brain that “This chilli is HOT!” and results in the sensation of heat. 1,2,3 

Contrary to popular belief, the seeds are not actually the hottest part of a chilli.  It’s actually the white lining inside the chilli, the placenta, where the capsaicin is produced.3,4  

The perceived ‘hotness’ of different types of chillies is ranked on a scale called the Scoville Scale, based on the amount of capsaicin present.  This also varies within the same type of chilli, depending on the ripeness, growing conditions and other environmental factors.3,5 

Figure 1: Ranking of the ‘hotness’ of different types of chillies in Scoville Heat Units, using the Scoville Scale.4

Why do some people find chillies hotter than other people?

The amount of heat that you can tolerate depends on how often you eat chillies.6  Frequent exposure to the capsaicin compound in chillies de-sensitises the pain receptors (TRPV1) that detects it, meaning they respond less to the capsaicin and therefore create a lesser sensation of heat.6 

Why is milk so good for relieving the chilli burn?

To answer this, we need to understand some basic biology.  There are two types of molecules: hydrophilic (water loving) and hydrophobic (water repelling).7  Capsaicin is a hydrophobic compound.1  The casein protein in milk is also hydrophobic.7  As like dissolves like, this casein is able to react with and remove the capsaicin and help to ease and sooth the burn.3,8  Whereas, water does not contain this casein (or any protein for that matter), and given that capsaicin essentially has a phobia of water, drinking water is not able to relieve the burning feeling.

So, for me, a bird’s eye chilli is about as high as I can go, but with a jug of milk handy, who knows?



Author: Amy Rowe, Dillicious Intern 2022

3rd Year Bachelor of Nutrition Science Student, Monash University



Image of Chillies by Shane Kong on Unsplash  



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