Do Leftovers Get Less Spicy Once You Refrigerate Them?

When you truly love a dish, it's always a good idea to cook more than you need. After all, who doesn't love leftovers? While this works for most dishes, it might be a mistake to extend a spicy meal because, allegedly, it becomes less spicy after refrigeration. That's the word on the street, but to separate myth from reality, we sat down for an exclusive chat with Kantha Shelke — a certified food scientist, principal at food science and research firm Corvus Blue, and senior lecturer of Food Safety Regulations at Johns Hopkins University. 

To break down this phenomenon, Shelke says we first have to understand what makes food spicy. The familiar burning sensation of spicy dishes comes from tiny molecules in the food, like capsaicin in spicy hot peppers, and piperine in black pepper. "[These compounds] create a spicy sensation by activating heat-sensitive receptors (TRPV1) in the mouth that signal the brain as if exposed to actual heat," Shelke explains. She adds, "Refrigeration does not reduce the amount of these compounds, but can tone down the perception of heat."

When the temperature of our dish goes from hot to cold, the nuances of flavor feel dulled. This happens for a few reasons. "Cold temperatures numb the mouth, and numbed TRPV1 receptors are not as sensitive in detecting capsaicin," Shelke says. This makes the familiar burn of spicy foods less intense — and Shelke says that it doesn't just affect taste. "Cold temperatures suppress aromatic volatility," she explains, "which can dampen the perception of flavor intensity and spiciness."

Colder temperatures don't just trick our taste buds — they literally change the makeup of our food. "Refrigeration cools foods, solidifying fats which temporarily trap these compounds, making them less available and lowering their impact on the palate," Kantha Shelke explains. While congealed fat can trap spicy molecules, other aspects of the dish will, too. "During refrigeration, flavor compounds in spicy foods tend to get absorbed by the starches and fibers in the food," she says.

So, while spicy food doesn't technically lose its fire in the fridge, our mouths have a harder time perceiving it. That's good news for spice lovers, but how do we make leftovers lend the same delicious burn they started with? "The best way to reheat refrigerated spicy food so as to preserve flavors and heat is with gentle and slow heating to protect the delicate aromatic compounds that give the dish its character," Shelke says. 

To do this, try adding a splash of broth or water to leftovers and stirring as you reheat. "When microwaving, use short bursts, stirring in between to avoid hot spots that expel the volatile compounds and mute spiciness and flavor," Shelke says. These techniques will also loosen any congealed fats and starches while re-exposing the hidden spices. Still, before you eat, Shelke suggests adding one final touch of spice, such as a drizzle of chili oil, or a splash of lime. "A squeeze of citrus can reawaken the dish," she says, "restoring its vibrant heat and complexity."

While it's great to know our spicy leftovers can be saved, Kantha Shelke says this phenomenon can actually come in handy if you accidentally make a dish too spicy. To keep that hidden heat contained during reheating, she has a few suggestions. To start, try simmering your dish for a prolonged period to cook off some of that excess spiciness. If you don't have the hours for longer cook times, high heat can work the same magic, breaking down the spice levels of your dish yet again. If that doesn't work, incorporating some mellow ingredients can also do the trick. "Adding butter, cream, coconut milk, or even yogurt ... can coat and soften the impact of spicy compounds," Shelke says. 

Finally, if all else fails, Shelke suggests dispersing some of the spiciness across your dish by adding in additional starches. "Cooking spicy food with rice, bread, potatoes, or noodles," she explains, "can absorb some of the spice into the starch network and reduce intensity per bite." 

If the heat is still too overwhelming, cloves can help temper a spicy dish. And if that doesn't work, it might just be time to rework your recipe, or learn how to increase your spice tolerance. Sorry!