
What makes food spicy and how to build a tolerance to it – experts on the science behind the spice and their tips for how to handle the heat
- Do you love spicy food? Wish you could eat more of it? The science behind why some of us love the burn spice gives us, and how to build up a tolerance to it
- A chef explains how she came to appreciate spice, another says Indian food is misunderstood, and a scientist reveals why not all spicy foods are created equal
From sriracha sauce to chilli pizza, the characteristic heat of spice is in many foods and various cuisines. Sometimes it is a tangy sweet spice. Other times it is a nuclear sensation that can set your whole mouth on fire.
Foodies have grown more adventurous over the years, going outside their comfort zones to try spicier dishes.
We decided to uncover the science behind the spice, find out how restaurants incorporate that characteristic heat into their dishes and answer a burning question: is it possible to build a tolerance to spicy food?
What makes food spicy?
When we sip something hot in temperature, nerve endings in our mouths activate and send a message to our brains: “This is hot! Don’t burn yourself!”
A similar process happens with spicy food.

In other words, the capsaicinoids trick our brains into thinking something is burning in our mouths, even though it is not.
Capsaicin is the most pungent of the capsaicinoids in a pepper, says Alissa Nolden, an assistant professor in the department of food science at the University of Massachusetts Amherst, in the United States.
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In graduate school, Nolden led an experiment that investigated whether drinks like water, milk and cola were better or worse at alleviating the burn from spicy foods. She found that milk worked the best.
Jalapeño and cayenne peppers contain capsaicin, but the heat in wasabi or black pepper stems from different chemicals that activate different nerve endings.

Nolden says scientists are not sure why some people cannot get enough of spicy food, while others cannot get far enough away.
For Anastacia Quinones-Pittman, executive chef at Mexican restaurant José in Dallas in Texas, enjoying spicy food took time. “I can’t eat a meal without having some sort of level of spice or something on the side to bite into,” she says. “But growing up, it just wasn’t my jam.”
During her childhood, Quinones-Pittman used to tie a red ribbon around a serrano pepper and place it near her father’s plate for Thanksgiving dinner as a joke, since he could not eat a meal without heading to the fridge for a pepper to chew on.

Returning home to Dallas after college, Quinones-Pittman gained a new appreciation for spicy food, won over by the flavours of roasted tomatoes and garlic in her family’s salsa.
At José, the restaurant’s aguachile, a seafood dish that usually features lime-cured shrimp or ahi tuna, is always served spicy. Its camarones à la diabla dish has a nutty spice and includes a guajillo purée and chile de árbol, a small but potent Mexican chilli pepper.
If guests like their dishes even hotter, the restaurant usually has one of three spicy salsas stashed in the back. José’s “knock-your-socks-off spicy” serrano, golden habanero and black habanero salsas are made for the staff, but Quinones-Pittman says they will bring one out if available when guests ask for that extra kick.

Spice, not spicy
“That’s how I grew up,” she says. “Going to school, coming back from school, [having] that spicy, tangy food.”
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The spice in Indian food is often misunderstood, she says. There is a difference between the spices like cumin, cinnamon and black pepper in garam masala that give a dish its flavour, and the green and dry red chillies that bring the heat.
“Spice is not spicy food,” Shah explains. “It’s a flavourful blend of spices, which is incorporated with the food.”
Different regions of India incorporate different levels of heat. When a guest orders malai kofta, fried vegetable balls in a creamy sauce, Shah says the dish can only be enjoyed at a mild to medium spice.

On the other hand, Sawaii’s Kolhapuri mutton – a goat dish from the state of Maharashtra – is a spicy favourite. “It will make them just [say], ‘Oh my goodness, it’s very spicy, I’m sweating’,” Shah says. “But they enjoy it.”
Nikky Phinyawatana, owner of Dallas-based Asian Mint, says the best spicy Thai dishes to try at her restaurants are basil dishes like pad kee mow, or drunken noodles; and pad krapow, a chicken and shrimp basil stir fry. “It is a softer, fresh chilli spice that you’ll even get to enjoy with the spice of garlic,” she says.

Can I build my spice tolerance?
Have restaurants seen customers increase their spice tolerance over the years? “One thousand per cent,” says Quinones-Pittman. She says people may be travelling more and interacting with different cultures and cuisines that help them gain an appreciation for spicy food.
“I know it did for me,” she says. “Every time I go to Mexico, there’s a salsa or a chilli powder or something on the table. It’s definitely helped me appreciate it more.”

Food scientist Nolden says the food we eat when we are younger can help develop our preferences when we are older. But for people who did not grow up eating spicy food, not all hope is lost. Repeated exposure to capsaicin, the chemical that makes some peppers spicy, can increase our tolerance.
“If you’re an adult and you’re choosing what you’re eating, and you start incorporating spicy food into your diet, you can definitely learn to [tolerate] spicy foods,” Nolden says.
So it is not too late to give spicy food a try, one hot pepper at a time.
