Capsaicin & chilli heat - it's not too hot to handle

And now to the often-asked question - what makes chillies hot? Well, the short answer is... Capsaicin!

The heat of a chilli pepper is referred to as its pungency. But there are several other more common terms we use to describe this sensation - ranging from tingle, zing, burn, scorch, bite and all the way to even painful! All give an idea of the feeling we get when we eat chillies, which by the way, except for the last one perhaps, is pleasurable :-)

Chillies contain chemicals known as capsaicinoids which are odourless and flavourless. Of these, most of the pungent, fiery nature of chillies is due to the primary capsaicinoid called "capsaicin", closely followed by "dihydrocapsaicin". Together these two compounds are responsible for around 80-90% of a pepper's heat. It is found in high concentrations in the internal membranes and placental tissue (the white 'ribs' which run down the chilli and hold the seeds) of the chilli pods. Large amounts are also found in the pith around the seeds - this is thought to be due to their close contact with the placenta, as the seeds do not actually produce the chemical compound. So the hotter the pepper, the more capsaicin it contains.

Capsaicin is an irritant to humans and it produces a hot sensation in any tissue it touches. When ingested, it binds with specific receptors in the mouth. These receptors can also be triggered by heat or physical abrasion, so they must be the same ones that are affected when you gouge and scorch the roof of your mouth with that extra hot grilled cheese on toast!! When the receptor is activated, it allows calcium ions to enter via the cell membrane and this in turn results in a pain signal to the brain When it binds to these receptors, it therefore produces the same effect that excessive heat or abrasive damage would cause. Hence the reason its fieriness can be described as a burning sensation.

The brain's response to this burning sensation is to raise your heart rate, release endorphins (a natural pain-relieving hormone) and induce perspiration. This can account for the huge popularity of chillies as endorphins produce a temporary feeling of well-being and this 'high' can be quite addictive for some. Also the perspiration produced from eating spicy foods can have a cooling effect on the body, as the sweat evaporates, which is especially important in hot countries. Not to mention the various reported health benefits from consuming chillies and spicy foods in general!

Capsaicin/capsaicinoid - Good to know...

• The pungency of the chillies will vary depending on the conditions under which they are grown (such as climate or soil), from one species to the next and when they are harvested (as the quantity of the chemicals increases as the fruit ripens and matures).
• The intensity of a chilli is not diminished by either cooking or freezing, so the only way to reduce it's heat is to remove the internal membranes and seeds.
• It is only slightly soluble in water but easily soluble in oils, fats and alcohol. So water would just spread the fire around your mouth!
• Although a cold beer is the usual remedy for extra (chilli) hot food, it is believed the small percentage of alcohol contained in this is not likely to wash away much of the compound responsible for this. Also, as a solvent, it will break the molecules loose but may just spread them around, instead of neutralising them.
• Alcohol is not as effective as milk which contains 'casein' (a fat-loving, or lipophilic, substance). Casein surrounds the fatty capsaicin molecules and pulls them away from the sites where they bonded with the nerve receptors. It then removes the heat-causing chemical in a similar way to soap washing away grease. So milk and its products such as yoghurt and ice cream will relieve that chilli burn.
• It is about 1000 times hotter than zingerone (the active ingredient in ginger which gives its pungent taste) and around 70 times stronger than piperine (the spicy component found in black pepper).
• Those which have shorter chain lengths burn for shorter times and affect the front of the tongue. Those with longer chains tend to produce the long, slow burn and affect the back of the palate.