Ann Reardon

The Science of Spicy Hot Foods


Why are chilli peppers hot?
A chemical in chillies called capsaicin stimulates the thermoreceptors (detect mild temperature changes) and nociceptors (detect pain) on your tongue. This incorrectly gives the brain that the tongue is burning. This sensation is temporary and will decrease in time.

Carolina reaper

Why do some people tolerate spicy foods better than others?
Eating chilli peppers regularly can decrease the nerve receptors sensitivity to capsaicin. Another theory says that these people still do feel the burn, but they enjoy the experience. Much like some people enjoy the thrill of heights and show rides.

What is the Scoville scale?
The Scoville scale was invented by Wilbur Scoville to rank different chilli peppers according to their pungency. He outlined his method in 1912 in The Journal of the American Pharmaceutical Association, volume 1, pages 453
The method I have used is as follows: One grain of ground capsicum is mac- erated over night in 100 cc. of alcohol. After thorough shaking, filtered. This alcoholic solution is then added to sweetened water in definite proportions until a distinct but weak pungency is perceptible on the tongue.
By this method, Japan Chillies tested 1 in 20,000 to 1 in 30,000, Zanzibar
Chillies 1 in 40,000 and 1 in 45,000 (two lots), and Mombassa Chillies 1 in 50,000 to 1 in 100,000.
The above description of the method is too vague to follow but if you want to carry out the test yourself detailed standardised methods can be purchased here

For a pungent chilli like Carolina Reaper the dried chilli is ground to obtain particles of size of approximately 1 mm. A sample of 0.050g is weighed and put into a flask with 50mL Ethanol, 95 % (VW) solution. The flask is then stoppered and shaken vigorously for 1 minute, left for 30 minutes then shake one minute, rest 30 minutes, shake one minute, rest 30 minutes, shake one minute and then leave to stand for 15 hours.
The extract is filtered through a dry fine filter paper into a beaker. Five mL of this extract is then transferred to a flask and diluted up to the 100mL mark with ethanol.
From this diluted extract take a quantity (0.67mL,0.72mL,0.77mL,0.83mL,0.91mL,1.00mL,1.06mL,1.11mL, 1.18mL,1.25mL,1.33mL and 1.43mL) and put it into a 50mL volumetric flask, dilute to the mark with sucrose solution (50 g/l Solution).
Five tasters are then instructed to rinse their mouth with water before and after tasting each solution. They must wait 5 minutes between each tasting. They are then given 5mL of the most dilute sample and instructed to swallow it immediately. Assessors then take note of the first dilution at which the person records a positive response to tasting the pungent sensation of chilli 20-30 seconds after swallowing.

The dilution factor is then calculated. The Scoville index for the product is the highest value of the dilution factor recorded for at least three out of five of the assessors.

Because this test involves human taste perception results are subjective. The preferred test now uses high pressure liquid chromatography to measure the amount of capsaicinoids present in parts per million. This can be multiplied by 16 to get an estimated equivalent value on the Scoville scale.

What is capsaicin extract?
Capsaicin can be extracted from chilli peppers so you end up with a very pungent thick liquid. When further purified and dried capsaicin is colourless and odourless and is 16 million scovilles. Caution should be used if your are cooking with or tasting anything that contains capsaicin extract. A tiny drop bit on the end of a toothpick can be as pungent as eating a whole chilli pepper.

The video below explains the process of extracting capsaicin from chillis. Take note of the amount of dried chillis that are used to get a tiny amount of extract.


How can you soothe the burn from Chilli?
Milk – The casein (one of the milk proteins) binds to the capsaicin and helps soothe the burn. Swirling it around your mouth is more effective than just drinking it. One test found milk to be one of the most effective beverages for soothing pungency from chillis.
how to soothe the burn of chilli peppers

Vegetable Oil– Capsaicin dissolves in oil not water. One study found that rinsing the mouth with oil decreased the sensation of heat by up to 75%. To make it more palatable in our video I mixed together melted milk chocolate with canola oil in equal parts. This also adds sugar and casein into the mix giving it multiple ways to effect the capsaicin.

Blocking Your Nose– the same study showed that blocking your nose decreased the pungency of capsaicin in the mouth. We did not find it to be effective so it may only be useful in a test situation where you block your nose before you eat the food.

Concentrated Sugar Water – Capsaicin binds to most sugars. A solution of sugar swirled around the mouth or sucking on a sugary sweet can be surprisingly effective at reducing the burn. For this video I used equal eights of sugar and water, heated it until the sugar was dissolved and then allowed it to cool to room temperature.

Which one is best?
In my own personal experience concentrated sugar water and chocolate oil were the most effective to stop the burn on the tongue. Swirling it around like mouth wash and using your teeth to scrape across your tongue while the liquid is still in your mouth also helps to move the capsaicin off your tongue and into the liquid.
If the burn is at the back of your throat then it is more difficult to swirl the liquid around the area. Gargling may help but I did not try that. Drinking milk was a good option for the back of the throat as you can swallow lots of milk, I don’t recommend that you drink large amounts of sugar water or oil.

My Cookbook

ann reardon crazy sweet creations cookbook
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All recipe quantities in the book are in grams, ounces and cups.

2 Comments View Comments

  1. Rating: 5

    Hey… tried tempering my chocolate in the microwave using the method 10 sec stir 10 sec stir 5 sec stir……….but my chocolate still didnt set at room temperature. Are there any other ways that I can temper using just a microwave?
    Thanks for all the videos! 😍😍😇
    Watch them everyday!

    • same for me 🥴😩

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