So Hot Right Now: Why We Love the Chile Pepper

Gastropod - Cynthia Graber and Nicola Twilley

Gastropod explores the science, history, and cultural impact of chili peppers, from their evolutionary defense mechanisms to their global cu

Key takeaways

• Chili peppers evolved capsaicin to deter mammals but not birds, allowing seeds to survive passage through bird digestive systems.
• Capsaicin is primarily concentrated in the white placenta tissue, not the seeds, which explains why removing seeds doesn't eliminate heat entirely.

Main topics

• Evolutionary biology of capsaicin
• Chili peppers as food preservatives

Notable quotes

"It's painful to most animals. Taste buds and they avoided them, but birds didn't." – Denise Kuhn

Conclusion

Despite the intense pain caused by superhot chilies like the Carolina Reaper, humans have evolved a deep cultural

Transcript preview

Speaker 2 (0:00) It's incredible. This is Speaker 3 (0:03) you on Carolina Reaper Pepper, huh? I know. It just keeps giving and giving. Speaker 2 (0:12) It's just like, oh, no. Anyway, I was just like, can you imagine if I rubbed my eyes? I'd be in the emergency room. Oh, dear. Speaker 2 (0:23) Anyway, kids, don't try Carolina Reaper at home. Speaker 3 (0:29) Do not. Do not even open the jar. Do Speaker 2 (0:32) not even have a friend ship you the jar. Speaker 3 (0:37) I promise I was not trying to unleash a chemical bomb on Nikki and her husband Jeff. The lid to the jar of Carolina Reaper chili powder apparently came off in the mail. She was coughing throughout our entire next recording session. I'm Speaker 2 (0:49) this close to reporting you to HR, Cynthia, except that we don't actually have HR at our two-woman show. But really, however mad I sometimes make you... That was not acceptable behavior in the workplace. Speaker 3 (1:02) I do still feel bad about it. I mean, the guy who sold me all the chilies we bought for this episode, including the Carolina Reaper, he told me we have to be so very careful with it. He was in pain for 20 minutes just from pouring it into jars for sale from inhaling the dust. I do literally know how he feels, sadly. Yes, this episode, we are deliberately subjecting ourselves to the chili pepper burn. And Speaker 2 (1:24) not just any chili pepper burn, but the hottest chili pepper. in the world. Speaker 3 (1:28) That's what we do for you, dear listeners. We, of course, are Gastropod, the podcast that looks at food through the lens of science and history. I'm Speaker 2 (1:34) Cynthia Graber. And I'm Nicola Twilley. And normally, I really like chili peppers. I have lots of different dried ones in my spice cabinet and all kinds of fun fermented hot sauces. chili crisps, salsa matcha in my fridge. So I was looking forward to this episode. Unsurprisingly, I have pretty much the Speaker 3 (1:52) same setup in my kitchen as Nikki does. I have hot sauce on the table for nearly every meal, including breakfast. But I started to get a little nervous hearing her cough, which made me wonder, why do we humans love something that sometimes feels Speaker 2 (2:05) like it's trying to kill us? The chili is botanically a berry, for heaven's sake. Why is it so hot and spicy rather than just sweet Speaker 3 (2:12) and fruity? How did this rather assertive berry spread from its home in South America and conquer, well, almost the entire world? To the point where I can't even imagine Indian or Chinese or Nigerian food without it. And why was the U.S. and Northern Europe so slow to catch on? All that plus the rise of the superhots. Speaker 2 (2:30) Is there a limit or will chilies finally Speaker 3 (2:32) actually kill us? This Encore episode was made possible thanks to generous support from the Alfred P. Sloan Foundation for the Public Understanding of Science, Technology, and Economics, as well as the Burroughs Wellcome Fund for our coverage of biomedical research. Gastropod is part of the Vox Media Podcast Network. Speaker 1 (2:53) The city moves fast, but your vibe, that's different. Sharper, smoother, more alive. The new Honda City isn't just made to drive, it's made to feel. The new Honda City, all new vibe. Speaker 1 (3:20) Our earliest childhood memories can feel so visceral. I have this memory of my mother standing on the beach, you know, the wind whipping her hair and her jacket, calling Speaker 5 (3:32) into the wind with my siblings out in the lake and the dam, you know, looming in the distance. But Speaker 1 (3:40) none of these memories were true. This week on Explain It To Me from Vox, why can't I remember being a baby? Speaker 3 (3:51) This might sound like a just-so story, but why is Speaker 2 (3:55) the chili pepper hot? To answer that, we spoke to Maricel Prasilla. She's a chef and a culinary historian, and she wrote an incredibly beautiful book called Peppers of the Americas, which traces chili peppers all the way back to their South American origins. So Speaker 8 (4:09) the four bears of today's peppers and tomatoes split off from a common ancestor of a... 20 million years ago in South America. Speaker 3 (4:18) Maricel says back then, millions of years ago, peppers looked and smelled like a tasty snack to the animals in the region. Speaker 2 (4:23) Which was a problem because the chili peppers' precious seeds would get destroyed in most animal guts and chili peppers want to have baby chili peppers. And so chilies developed a defense strategy. Speaker 8 (4:34) A devilish, you know, non-poisonous thing in the form of capsaicin, which is an alkaloid. So it's painful to most animals. taste buds and they avoided them, but birds didn't. Speaker 7 (4:46) Birds have this amazing ability to not feel the heat sensation because they don't have the same heat receptors in their mouths or their skin Speaker 2 (4:55) the way we do. Joining the chili chorus is Denise Kuhn. She's a chili pepper researcher at New Mexico State University, home to the one and only Chili Pepper Institute. Speaker 7 (5:04) And so they can eat lots and lots of these tiny hot little berries and pass it through their digestive system. unarmed and grows into a new plant. Whereas us mammals, we can feel the heat and it passes through our digestive system and actually our, our system destroys the seeds. So it can't grow into a new plant. And that's kind of why we think that the chili pepper plant evolved capsaicin was to keep mammals from eating them, but then look at what we go and do. Speaker 3 (5:33) Denise told us chili peppers are the only plants in the world that produce capsaicin. And because chilies are making capsaicin to protect their precious seeds, they put most of that protection right around those seeds. Speaker 6 (5:44) And if you cut a pepper open, even if it's a bell pepper with no capsaicin at all, you notice that the seeds on the inside are attached to a white tissue. which the botanists call placenta because it supports the developing embryo as it develops. And it turns out that most of the capsaicin in chili plants is found in that supporting material in the placenta. Speaker 2 (6:13) Listen up. This is Harold McGee, star of our recent Smoke episode, author of Nosedive and on Food and Cooking, and all-round food science whiz kid. And he is correcting a common misperception. A lot of people think that most of the heat in a chili pepper is in the seeds, but he says no, it's mostly in the white placenta stuff. Speaker 6 (6:34) The thing that happens, though, is that if there is a lot in the placentas, during the drying process, as the fruit shrinks, It's easier for the capsaicin in the placenta to spread around the interior of the fruit. And so it's much more difficult to kind of pick out the placenta and minimize the heat once the chilies have been dried. Speaker 3 (7:00) So this is why and where chilies are spicy. But if the point was to put us off from eating them, then why did early humans in what's now Peru and Bolivia give them a try? Speaker 8 (7:08) Prehistoric hunter galleries must have been curious. about these beautiful scarlet pots and they experimented. with specimens that they found close to their own settlements. Speaker 2 (7:19) Some of these wild peppers would have been more spicy and some less. Different plants and even different fruits on the same plant can have more or less Speaker 3 (7:27) capsaicin. But there's one particular reason that ancient hunters might have preferred the spicy ones. Capsaicin naturally repels insects, but sometimes those insects might mistakenly take a bite of a pepper. But even with insect bite holes in them, the damaged berries wouldn't have gone bad. And that's because capsaicin also fights off fungus. A fungus Speaker 2 (7:45) -free pepper. will last longer, which is great for a human that wants to eat it, and the capsaicin in it might even prevent other food from going moldy. That's even better. The researchers who discovered this connection between insect bites and capsaicin levels, their theory is that humans might have deliberately sought out and added the spiciest peppers to their foods as a kind of early preservative. Speaker 3 (8:07) kind of like garlic. And Maricel thinks there was another reason that early humans in South America were so attracted to peppers. She visited the archaeologist's site where some of the very earliest pepper seeds from food were found. And she saw villagers who live nearby the site preparing food from corn, root vegetables, shellfish, and not much else. Speaker 8 (8:24) So it struck me that what elevated, you know, this type of cooking from subsistence rations to a true cuisine was the skilled use of peppers. So the local ajillas. that I had seen women crushing into sauces. Speaker 2 (8:38) These chili peppers, they're called aji locally. Maricel says they're doing two different things. They make the bland starchy food more interesting, for sure, more flavorful and spicy. And the irritation of the capsaicin, that stimulates your mouth to produce more saliva. And saliva contains an enzyme that breaks down starchy foods. So chilies make starchy foods less boring to eat. and easier to digest. Speaker 3 (9:03) Honestly, the pep from the heat, in addition to all the great flavors and chilies, that spice can kind of make food more exciting. It really does literally add some Speaker 2 (9:11) zinc. I mean, how many terrible sandwiches and on-the-road breakfasts have you rescued with some hot sauce? All of Speaker 3 (9:17) them. All of this explains why we might have been attracted to peppers. But it's been hard for scientists to figure out how long we've been eating spicy peppers. Mostly that's because in the hot, humid regions where many of the earliest peppers grew, the seeds and all the rest of the plant disintegrate really quickly, which made one site in Peru really exciting. The Speaker 8 (9:34) site is called El Brujo, the shaman, and it has been occupied continuously. for as long as we have evidence of human beings in Western South America. So you find temples and subterranean dwellings, burial chambers, the remnants of successive civilizations. But to me, one of the most important sites in the complex is a... huge, dark-colored mound called Huaca Prieta. Speaker 2 (10:00) Maricel told us that Huaca Prieta was first excavated in 1946 by an archaeologist from the American Museum of Natural History. Speaker 8 (10:09) And they started excavating this mound. They found dwellings and kitchens. They found ancient garbage dumps and latrines in the stages of their exploration. So they were peeling layer by layer of history. The refuse heap was actually much more exciting to them than any, you know, jewels, because organic matter is very difficult to combine. But Speaker 3 (10:35) there was plenty of it at Huacaprieta, so the archaeologists took samples of the fossilized poop. They had it analyzed using the new technique at the time of carbon-14 dating to get a better read on how old it was. But even more exciting, they sent that poop to a guy who founded an entire new field of research that uses ancient poop to figure out what ancient people ate. And this guy Speaker 2 (10:55) concluded that 7,500 years ago, the people who lived at this site were eating not just one, but a few different kinds Speaker 3 (11:02) of spicy peppers. Probably then and still today, there are around 30 species of wild peppers. At some point around the time, the El Brujo people were eating chilies, or since then, nobody really knows, we domesticated five species that we still enjoy today. Now, Speaker 8 (11:16) the most important of these species is Capsicum annum, which is believed to have been domesticated in what is today Mexico. So these five species basically have their niches historically. There were places where they were domesticated. First, Speaker 2 (11:33) Maricel compares the five domesticated chili pepper species to the five alliums, garlic, chives, onions, leeks, and shallots, in terms of how different they can be in their flavor personalities. Speaker 3 (11:45) Anem is the most common domesticated chili, and so, unsurprisingly, it's the most diverse. Basically, all the dozens of peppers you might eat in Mexico are anems. Jalapenos, poblanos, bell peppers, Speaker 2 (11:55) all anem. Then there's chinense, of which the most famous is probably habanero. Number three is Bacatum, which you mostly find in Peru. And then there's number four, Frutescens, which Marisol says is the most one note of the chili pepper family. It's just kind of... sharp and hot. The most famous frutescens is Tabasco. The fifth and Speaker 3 (12:14) final species is called pubescens, and this one we almost never eat in the U.S. or Europe because it doesn't dry well, and so mostly people eat it fresh in South America, or it gets shipped frozen and you might find it under the name Rocoto or Locoto in Latin American restaurants. Speaker 2 (12:28) All of the five have different heat profiles and different flavor notes as a species, and then there's obviously a huge amount of variety within the species, and really... We just needed to try them. We had eight Speaker 3 (12:39) different dried chili peppers lined up in front