Kendra Pierre Louis: So in general, I do not like savory, creamy foods, so I don't eat butter. I don't like alfredo sauce. Yeah, like ranch. Why?

Dan Pashman: This is climate and science reporter Kendra Pierre Louis. And she really doesn’t like mayonnaise.

Kendra Pierre Louis: I probably should introduce myself as my name is Kendra Pierre Louis, and I'm the author of “The Story: Mayonnaise is disgusting and Science agrees”. 

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Kendra Pierre Louis: It is also the first story, maybe the only story I've ever done that had like an industry trade group try to get my boss to take it down. 

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Dan Pashman: This is The Sporkful, it’s not for foodies it’s for eaters, I’m Dan Pashman. Each week on our show we obsess about food to learn more about people.

Dan Pashman: Today, our show comes from our friends at Gastropod. It's a really great podcast that looks at food through the lens of science and history. It’s hosted by Cynthia Graber and Nicola Twilley. And in this episode, Cynthia and Nicky look at the mysterious world of food texture. Now, I give a lot of thought to texture. I'm a big texture eater. But texture is something you haven't given a lot of thought to. Still, it’s a huge part of why we love and hate certain foods. The science of texture was a big part of Kendra Pierre Louis’s story, you heard referenced at the start of the show, which again was entitled, “Mayonnaise is Disgusting and Science Agrees”. Here’s that episode of Gastropod, featuring hosts Cynthia and Nicky, we’ll pick up with them talking to Kendra. Here’s Nicky: 

Nicola Twilley: Mayo is actually a food I hated as a kid for both texture and taste reasons. Although now I'm supposedly a grown up, I can't really find it in me to hold a grudge against mayo anymore. That said, it is an extremely hated food.

Kendra Pierre Louis: And I know that about 20% of people worldwide by like the one measure that I could find don't like mayo. So like I am in a sizeable minority. And my feeling is that there's also just like a large number of people, kind of like Nicky, who have just given up. Like ... 

Nicola Twilley: That's me!

[LAUGHING] 

Nicola Twilley: I given up books! 

[LAUGHING]

Nicola Twilley: It's more applicable than you know 

Cynthia Graber: No comment. But so I'm not going to hazard a guess as to why mayo in particular is so hated. Personally, I actually love it. I even make my own aioli, which is just garlic mayonnaise. But Kendra isn't the only one who has a strong opinion about creamy foods.

Kendra Pierre Louis: Just a little too much. Like little too — eww, like, intimate or something? I don't know. I don't know how to describe it.

Nicola Twilley: So what on earth is up with creamy? Or for that matter squishy and slimy? This episode is all about the many mysteries of food texture. And this is, of course, Gastropub, the podcast that looks at food through the lens of science and history. I'm Nicola Twilley and I love gummy things and I used to hate creamy things before I gave up. I still don't really like stringy things. 

Cynthia Graber: And I'm Cynthia Graber and I love most textures. I love crunchy foods, creamy foods, gummy foods, all good. But like Nicky, I'm not a particular fan of stringy foods. Kendra disagreed with us on this one. 

Kendra Pierre Louis: The stringiness is a real problem for me. 

Cynthia Graber: Spaghetti squash should be thrown out the window. 

Kendra Pierre Louis: Yeah. 

Cynthia Graber: Like, why do people — and why do people think it's pasta? Like, the texture is ridiculous. 

Nicola Twilley: I don't know about that. Yeah.

Cynthia Graber: It doesn't taste like anything. 

Kendra Pierre Louis: Yeah. That's why it's good though. But also, like the texture, But also the reason that it's good is that it doesn't taste like anything. So it's one of those things you can throw at anything and be like, Oh, I got my veggie for the day.

Cynthia Graber: Hmm. I guess I just — I love vegetables so much, and that's a texture I actually don't like. 

Nicola Twilley: Yeah, strangeness is kind of repulsive. I'm with you there. 

[LAUGHING] 

Kendra Pierre Louis: So much judgment. 

Nicola Twilley: Oh, yeah.

[LAUGHING] 

Nicola Twilley: And no shame about it. 

Cynthia Graber: Not at all. 

Nicola Twilley: So many strong feelings and so many questions, like why are foods, different textures and what's going on in our mouths when we feel all those feelings? 

Cynthia Graber: Do we all feel food textures the same? Like is a creamy dish to me the same as a creamy dish to you? Or do you think it feels kind of slimy or gritty? And is there a way to measure these strange sensations? 

Nicola Twilley: Plus, do all cuisines and cultures prized the same textures? Or is there a whole textural universe out there to explore? 

Cynthia Graber: This episode is made possible in part by the Burrrow's Welcome Fund in support of our coverage of biomedical research and by the Alfred Sloan Foundation for the Public Understanding of Science, Technology and Economics. Gastropub is part of the Vox Media Podcast Network in partnership with Eater.

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Matt: Hi, Gastropub. I'm Matt and I'm from London, and I love the texture of caviar. There's something about the way when you slowly chew it so that it just kind of gently pops and sounds a little bit like distant fireworks. Salmon caviar has a bigger pop, but it's more of a squish, which is really nice, but different.

Olivia: My name is Olivia. I'm from New Brunswick, Canada, and grapes and blueberries freak me out. I hate the texture because I don't like biting into the skin and then having it kind of gush in my mouth. And as a kid, it sort of reminded me of eyeballs. And every once in a while, as an adult, that kind of kicks back in and it just freaks me out.

Cynthia Graber: A pop and a squish. One person hates it, another can't get enough. 

Nicola Twilley: Horses for courses as we say in the U.K. Your eyeball is my caviar. But before we get any further down this road, what exactly is texture when it comes to food?

Bryony James: The really common ones are things like crispy, crunchy, gritty, smooth, hard, soft. You'll get into things like my mouth coating. A lot of people when they're eating ice cream will go, Oh, it's coating my mouth.

George Van Aken: It's grease in this crispiness, smoothness, thickness, hardness.

Cathy Erway: Creamy and crispy and crunchy. How do people talk about cake a lot? Like fluffy?

Ole Mouritsen: Hot or chewy or mealy or dry, squishy, oily. 

George Van Aken: All this kind of experiences that you can have are typically oral sensations are basically really felt in the mouth.

Nicola Twilley: So texture is just a whole bunch of different mouth feelings. 

Cynthia Graber: Usually when we sit down to dinner, most of us pay attention to how the dish looks and smells and tastes. We're often not even aware of how much we pay attention to how it feels, but we are actually noticing texture.

Bryony James: But if you say, How does this steak taste? They'll say, Oh, it's really nice. It's tender. And of course, tender is a texture word. So my research is in the the bits of food that are critically important to how much we enjoy it, but possibly people don't always articulate them as texture.

Nicola Twilley: Bryony James is a professor at the University of Waikato in New Zealand and she studies food texture. 

Cynthia Graber: A lot of different things are going on in our mouths at the same time that all combined into this thing we call texture.

Bryony James: Your teeth are obviously registering pressure and that will be translated into a perception of a hard texture.

Nicola Twilley: Your tongue is also sensitive to pressure and feeling whether something is soft or hard. This kind of sensation comes from what are basically touch receptors like you'd have in your fingertips. We have these touch receptors all over our bodies, but one of the places they're especially densely packed is on our lips and our tongues and in our gums.

Cynthia Graber: One way to think about these receptors in our mouth is like the springs on a mattress.

Ole Mouritsen: And if you sit on the mattress, the springs will deform, and if springs deform, the mattress will deform. So it's a combo system. So all the mechanical motion, you can imagine, it's sort of indentation on the mattress that will be picked up by the springs.

Cynthia Graber: One more texture expert to meet. This is Ole Mouritsen. He's a physicist based in Denmark and also one of the authors of a book called Mouthfeel How Texture Makes Taste. And he says, those receptors in our mouths are super sensitive to nearly microscopic changes in texture.

Ole Mouritsen: If you have an ice cream that is completely smooth, you don't feel any particles in the ice cream. But everyone knows that if little ice crystals are formed, you can actually feel it between the teeth. And then certainly your perception of the food, it changes.

Nicola Twilley: Astonishingly, our tongues are pretty much as sensitive as fingertips in terms of how accurately they can gauge particle size.

Bryony James: You're going to detect particles that are bigger than about 35 microns, and that will convey a gritty texture. So to give you context of that, the hair on your head is between 50 and 100 microns. So something about a third of the width of one of the hairs on your head, your tongue will go, oh, this is a particle. And if there's lots of that, you'll get a gritty, often quite unpleasant sensation.

Cynthia Graber: Most of us prefer ice cream, creamy, not gritty, with tiny little ice particles, as long as it's not supposed to be kind of icy like a granita. 

Nicola Twilley: But speaking of creamy, how do we sense it? I mean, it's not just the absence of grittiness or is it?

Bryony James:  Okay, so creaminess is a really, really interesting one. There's a bunch of things going on and a bunch of unresolved questions. But yeah, we're certainly closing in on this. Creaminess has a lot to do with particle size. So the smaller the particles, the creamier.

Nicola Twilley: So yes, one of the things going on in the food that's creamy is that the particles are just too tiny for our tongues to feel. But like Bryony says, it's more complicated than that. The absence of grittiness is not the only thing that's going on. Those receptors in our mouth, they're also feeling how the food flows over the tongue. How viscose it is. Viscosity seems to be another key element of creaminess.

Bryony James:  But also there's a fairly strong body of evidence that the body is extremely sensitive to the presence of fat, let's say. So even if it's concealed in other things, your brain goes, oh, there's a fat molecule there. And that can also contribute to the textural perception of creaminess.

Cynthia Graber: So creamy sounds pretty complicated, but then how about chewiness? I can imagine it's partly the way a particular food gives when you bite down on it, but that's not really the whole chewy sensation.

Bryony James:  So if you think of something like a really soft caramel or toffee or caramel, as Americans pronounce it, [LAUGHS] if you chew down on that, then of course you think about pulling your teeth apart. It's now pulling on the counter receptors. So a property called cohesiveness, how much something sticks together and adhesiveness, how much it sticks to your teeth, that's all from the same receptors, but just sort of working in reverse.

Nicola Twilley: These mattress spring receptors are in your teeth and also your gums. And when something is chewy, they're being stretched and compressed. 

Cynthia Graber: Another two common texture descriptions are crispy and crunchy. We can sense these textures partly because of how food feels and breaks apart when we bite down on it. But there's another mechanism going on at the same time, we actually hear the sounds that our teeth are making as we bite down on, say, a potato chip.

Nicola Twilley: So you're feeling texture through these receptors in your mouth, which are super sensitive. You're sensing texture through sound, too. And then it turns out you're even sensing texture outside your body before the food even gets to your lips.

Cynthia Graber: Kendra told us about some studies where researchers took a piece of bread and made one half stale and the other half still fresh, and they controlled which half people held before they took a bite.

Kendra Pierre-Louis: And if you're holding onto the stale and and you're biting into the fresh piece, you will taste that fresh piece of stale. And if you flip it so you're holding onto the fresh piece, but you're biting into the stale end, you will think that that piece is fresher than it actually is.

Nicola Twilley: This sounds weird, but it makes a ton of sense once you think about it, because it's all those same touch receptors, just the ones in your hands rather than in your mouth. 

Cynthia Graber: All of these receptors in our mouths being touched and pressed and stretched, and the receptors in our fingers and the ones that pick up the sounds that we hear, they all transmit that information to our brains. And our brains then make the connection between those sensations, and it creates our sense of what the texture of that food is. 

Nicola Twilley: So that's how we sense texture. But obviously, the texture is in the food. Texture is like a property inherent to food, and different foods have different textures. 

Cynthia Graber: For both animals and plants, that inherent texture has to do with the structure and makeup of cells. And then also how those cells are arranged. An apple is crispy and juicy because the cell walls are rigid and they keep water in. That water bursts when you break the cell walls with your teeth.

Ole Mouritsen: I mean, think of having an apple which is overripe and you bite in this overripe apple. And then you say, well, it's taste mealy, which of course, not a taste, it's a sensation and is dry.

Nicola Twilley: And that mealy dry texture is a direct result of the fact that the cell walls have become floppy rather than rigid. And so they don't crunch when you bite into them anymore. 

Cynthia Graber: That's how the texture of a food can change over time. But then there's how the texture of food changes over evolutionary time, how the environment shapes the texture of food.

Ole Mouritsen: So if you take land animals, our muscular structure is very much a consequence of the fact that we constantly have to work against gravity.

Nicola Twilley: It makes me tired just thinking of it. But then picture floating in the ocean like a fish. Like, sure, you have to have to swim, but you're all buoyed up and supported against the drag of gravity by the water.

Ole Mouritsen: And it means then that the way the muscles are built up and also the kind of skeleton of bones would be different because they don't have to support the weight because there's not much gravity. I mean, if you take a piece of salmon or tuna or some other fish, most people are probably wondered, how come this fish can be so strong and a furious fighter? But I can take the motion and I can poke my finger right through it.

Cynthia Graber: The reason is that although a tuna can swim fast for thousands of miles, it doesn't need to stay upright on land, whereas a cow does and so the fibers of a steak are built differently because of that. That large animal may be lazing around in a field of clovers, but it's constantly fighting the very strong force that is gravity. And so the muscles are tough. 

Nicola Twilley: Until you cook them. When you think about it, one of the main things that going on when we cook stuff is we're changing its texture. 

Cynthia Graber: Cooking can make tough meat tender by breaking down the fibers that keep it so tough. Cooking can also make grains easier to chew and digest by making them swell with water and explode. In an egg, cooking makes proteins clump together or rather coagulate and so they're not fluid anymore. 

Nicola Twilley: So, so far we figured out how we sense textures like creamy and crunchy in our mouths and also what makes certain foods have certain textures like tough versus tender. But obviously in real life, most of the things we eat aren't just a single texture almost.

Bryony James: Almost all foods will release a multiple series of textures and also they change with time. Very, very dynamic thing to study.

Cynthia Graber: As an example, Bryony introduced me to a cookie I'd never heard of before. It's called the Ginger Nut. 

Nicola Twilley: Ginger Nut is also slang for a redhead in the U.K. just FYI. Also, it's not the best biscuit in the tin to be perfectly honest with you. Picture a ginger snap that's thicker, harder, and grainier.

Bryony James:  It's a high sugar, low fat biscuit. So really, really hard. And most people won't try and attempt to eat a Ginger Nut unless they dunk in their tea. They're the classic dunking biscuit. So you give somebody a Ginger Nut and they bite into it. That is such a hard, hard biscuit that you could ask almost anybody in the world what texture you're perceiving. They'll say hard. Now, that doesn't mean that hard is the only texture. No, it's just the dominant texture at that moment in time. And then they crunch it up and the particles get smaller and smaller. They maintain the structure for a long time. So then people will start to say, oh, it's gritty, it's bitty. But then the sugars start to dissolve and things start to get sticky. So even this real simple, hard, hard biscuit goes through gritty, bitty, mouth coating, sticky, smooth, until they're finally ready to swallow it.

Nicola Twilley: And then with a sigh of relief, they vowed never to eat a Ginger Nut again. 

Cynthia Graber: I'll keep it in mind. That's how one food can change while it's in your mouth. But also a food might have a lot of different textures. And it right from when you bite into it, like a nut filled chocolate bar or a sandwich that has crunchy lettuce and squishy tofu and creamy mayonnaise. Yes, I do love mayonnaise. 

Nicola Twilley: This makes Bryonys and Oles, and anyone who wants to study food texture, it makes their life really hard. There's all these different textures. And on top of that, you really don't just experience textures on their own. You're also experiencing the taste and the smell of the food.

Ole Mouritsen: So it is a mess. If you allow me to say so, there are many different things that happen at the same time.

Cynthia Graber: And what's wild is that each of those sensations can influence each other. Texture can actually influence flavor and vice versa.

Ole Mouritsen: The most well known example with texture that is vanilla, that people that if you have a vanilla in some food, you perceive it as more creamy than without vanilla. There's something you can easily taste yourself.

Nicola Twilley: It's weird, but true. One theory is that this is just a learned connection that we're so used to, at least in the West, to vanilla custards and vanilla ice creams and vanilla yogurts that we just make that creamy vanilla connection.

Ole Mouritsen: But there's no physiological mechanism that dictates that these should — relatedly, the vanilla vanillin that gives the flavor of vanilla has nothing to do with creaminess. So it's all connections in the brain.

Bryony James:  So in a lot of ways, texture and something like taste, flavor, aroma, they're all so interlinked that you can't tease them apart. But we're used to thinking about taste. We used to talk about flavor and smell. So the texture one might be the hidden one, but is contributing to all the others.

Cynthia Graber: And Bryony says that although texture might be something many of us don't consciously pay much attention to, it's a bigger part of your food enjoyment than you think.

Bryony James:  I can give you any number of examples of that, but possibly the simplest one to start with would be chocolate. If you leave chocolate lying around a bit, you know, it gets that white bloom on the surface. And if you read the packet of a packet of chocolate biscuits, it says, don't worry about this, it won't affect that flavor whatsoever. And actually that's true and not true at the same time. So when chocolate does that, what's happened is the fat has changed a little bit. It's changed the melting point a little bit. So if you put that chocolate in your mouth, the texture that you experience is more like a wax candle and it didn't melt properly. All the flavor compounds are there, all the aroma compounds are there, but you don't experience them because the texture is wrong. So it hasn't released the flavor. So texture makes taste in a lot of ways.

Nicola Twilley: Again, it's something you don't really necessarily think about unless you're a chef or a scientist. But until food starts to break down in your mouth, it doesn't release all the chemicals that make up its flavor. So it's the texture of the food that affects how quickly those flavors are all released.

Ole Mouritsen: You have to make sure that all these wonderful things that gives you the pleasure, they are released at the right time scales in the mouth. They're not supposed to sit there in the food for so long that you have swallowed the food before they've made their effect. And similarly, they are not supposed to be released actually so quickly that you can't perceive them before it's all over.

Nicola Twilley: Imagine you had a starburst that was super, super, super chewy. It would run out of flavor before you were ready to swallow it. The Willy Wonka folks at Starburst central have to match the chewiness of the candy with the flavor release so that you get the maximum enjoyment. Ole I gave is another example. Imagine a thin broth based soup. You might slurp it all down before you even have a chance to register the flavor. The point is, texture sets up this balance between flavor and time in your mouth that you only really notice when it goes wrong. 

Cynthia Graber: So while I never thought about this before, I am now convinced that texture is really critical to our enjoyment of food. But my next important question is do we all experience texture the same way inside our own mouths? That's coming up after the break.

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Dan Pashman: Coming up after the break, Nicky and Cynthia look at the texture known as Q, which appears in foods like boba and mochi. They also talk to researchers who have to figure out exactly how to study and measure texture. It’s not so easy. That’s all coming up. Stick around.

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+++ BREAK +++

 

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Dan Pashman: Welcome back to The Sporkful, I’m Dan Pashman. And hey, Mother's Day and Father's Day are right around the corner. If you need a special gift, check out The Sporkful Collection Variety Pack from Sfoglini. You can get two boxes of cascatelli, and two each of my new shapes, vesuvio and quattrotini.  So you get six boxes of pasta, three different shapes to try. It's the perfect gift for that special parental figure in your life. Order now and get if shipped to your door from Sfoglini.com. That's S-F-O-G-L-I-N-I .com. And before we get back to the show, one quick note to check out last week's episode, featuring the one and only Bill Nye The Science Guy. We nerd out on everything from PB&J to GMOs. That one's up now, check it out. 

Dan Pashman: Okay, back to the episode of Gastropod that we’re sharing today, all about texture. 

Christy: Hey, Gastropub, this is Christy from Michigan. Well, as an autistic person, texture can kind of make or break a meal for me. I love crunch. I love crunch. I can't get enough. Anything mucilaginous or slimy is just kind of a deal breaker.

Hollis: This is Hollis from Anchorage, Alaska. I used to love hot dogs. I loved the way that when I bit into a whole cold hot dog, I got that kind of snap and then squidge against my molars.

Matt: I didn't use to like mushrooms as a kid, similar to many people. Like, it's the slimy thing, but now I do like them. I think really chewy, like anything that sort of really requires, like, gristle and like, breaking down that doesn't, like, melt away or, like, dissolve. It's just a no.

Nicola Twilley: So based on our super scientific poll, we can conclusively say that texture is actually a pretty big part of our feelings about food. And those feelings are often formed at a young age, like our mayo hating science journalist friend Kendra. Fortunately, it's not all hate. Her fervent disgust for mayo was matched by an equally passionate love.

Kendra Pierre Louis: My favorite food as a kid was tripe. I called it rubber meat.

Cynthia Graber: In case you haven't heard of it before. Tripe is the food word for cooked intestines. 

Kendra Pierre Louis: And whenever my mom cooked it, I would, like, go to town. And I think —

Cynthia Graber: [LAUGHS] I love this. 

Kendra Pierre Louis: I was such — like, I was such an underweight child because I was so picky and it was so difficult to eat. And I don't think she understood, like, why this child who, like, would blow up on her when she put Miracle Whip in a sandwich, was like, happy to wade through a sea of okra to get to the tripe, you know?

Nicola Twilley: Oh, my God. All of those things are disgusting to me. Miracle Whip, tripe and okra? No way. Nu-uh. No, thank you. Which just goes to show that individual eaters definitely have their own individual texture preferences. 

Cynthia Graber: And it's not just individual eaters. Entire cultures come with textural preferences.

Bryony James:  So different cultures have different lists of words and different ways of expressing texture and crisp and crunchy, depending on your culture are seen as very desirable textures. But then other cultures prefer soft and slimy. Now you say slimy to somebody who speaks English or American English. They go, ooh, that doesn't sound very nice. But when it's translated into Japanese or Chinese, it's a very desirable texture.

Nicola Twilley: In fact, Bryony and Ole both told us that the Japanese language is one of the richest when it comes to food texture words.

Bryony James:  They've got over 400 words, 400 unique words for different food textures.

Ole Mouritsen: I sort of asked myself, how come that the Japanese are very fascinated with seaweeds that have very mild flavors. It's not such something very strong like a spice, but it's mouthfeel. This fact you had to appreciate the particular tactile sensation of the different kinds of seaweeds when you chew on them.

Cynthia Graber: In general Eastern languages have words for textures that we don't really focus on in the West. Cathy Erway as the author of the cookbook The Food of Taiwan and she told us Taiwanese love a texture called Q.

Cathy Erway: Anything that is springy, bouncy, a little chewy. You know, a lot of people know mochi. That is a great Q texture classic.

Nicola Twilley: Mochi is delicious. If you haven't had it before. It's like a squidgy blob made out of rice flour. To me, it's always kind of felt like a slightly softer Japanese version of gummy candy.

Cathy Erway: I think it's a tooth thing. Yeah. My friend likes to describe Q as it springs from the teeth. So, you know, there's that resistance when you first go into bite.

Cynthia Graber: If you've had mochi ice cream bites, you'll know that there's that resistance and chew of the mochi before you get to the ice cream inside. And mochi is not the only place to find Q.

Cathey Erway: Tapioca pearls, you'll find in boba tea. That's another classic Q texture. I think also fish balls that are enjoyed in like East Asia have that bounciness to them.

Nicola Twilley: This springy, chewy, bouncy texture is always written just using the letter Q. Even in the middle of a sentence that's otherwise entirely written in Chinese characters. Which is weird because Q as a texture isn't a Western concept.

Cathy Erway: This was like a term that was really popularized in Taiwan in more contemporary times, and it derives from Taiwanese or Hokkien derived term, which is Q. It sounds like. Q But nowadays it's always spelled with just the Roman letter Q.

Cynthia Graber: Cathy says the word Q to describe food wasn't really around when she was a kid. If she wanted to describe a particularly toothsome fish ball?

Cathy Erway: I mean, I would say rubbery, but like in a good way. [LAUGHS] No negative connotations whatsoever.

Nicola Twilley: Although Q is not a word I use to describe texture, I do like the sound of all the foods Cathy described. So maybe I'm a secret Q fan, but the proof is in the tooth bounce, as they say. And so Cathy took us out on a Q adventure near where she lives in Brooklyn.

Cathy Erway: This is Mochinut. It specializes in mochi donuts, which is kind of like the best of both worlds.

Cynthia Graber: I'm pretty obsessed with mochi and I've had donuts, but I had never enjoyed the special treat that is a Mochinut. I was pretty excited. 

Nicola Twilley: But that wasn't the only Q deliciousness we ordered on our Q tasting menu. Cathy suggested a boba tea and then another tea with a different Q like jelly called aiyu jelly, which is made from a seed. 

Cynthia Graber: We also ordered something we hadn't expected, which was a hot dog on a stick. We ordered the kind without meat. It was basically mozzarella with a crust of potatoes and it looked like maybe it had some Q.

Cathy Erway: What about that? It is like incredible. It is a crispy potato crusted crispy thing.

Cynthia Graber: But there's like little pieces of potatoes you have. So you have — it's like this little knobbly, like lots of little potato bits fried onto something else. 

Nicola Twilley: This non dog hot dog on a stick was a whole lot of crispy, but there was also some Q. There was like a mochi rice flour breading on it. And because why not, also some stretchy mozzarella. 

Nicola Twilley: Maybe you can rip off a piece?

Cynthia Graber: I can try to rip off a piece. 

Cathy Erway: Yeah. 

[EATING MOCHINUT] 

Cynthia Graber: Oh, my goodness. 

Nicola Twilley: Wow.

Cathy Erway: [LAUGHING] 

Nicola Twilley: Okay, that's like all the textures in one.

Cynthia Graber: Weirdly, it's a little sweet, too. I feel like there's ... 

Nicola Twilley: Yeah.

Cathy Erway: I think it might be the mochi donut that is just, you know, on the outside of this cheese blob.

Nicola Twilley: Extremely intriguing. We washed this mochi potato cheese stick thing down with our Q filled teas. 

Cynthia Graber: The aiyu jelly is so much more just kind of tender and it melts really quickly, whereas the boba jelly is like this very toothy kind of chewy experience. 

Nicola Twilley: Yeah. Yeah. The aiyu jelly almost slithers down with the rest of the tea. 

Cathy Erway: It does. 

Cynthia Graber: And then we moved on to the main event, the Mochi Donuts or Mochinuts. 

Cynthia Graber: I'm so excited. It looks light, fluffy, everything perfect. 

Nicola Twilley: Yeah. These are good. 

Cynthia Graber: So this is my first machine donut. And I've already said I'm obsessed with mochi. It has so much more springiness to it than other donuts. It's just got this, like, bounciness, one might call it. Maybe a little bit of Q even?

Cathy Erway: It's like a completely slightly more elastic donut than we're used to. But I think it's — now, I was saying, like, I can't eat regular donuts because I want this too.

Cynthia Graber: I'm not going to turn down a regular donut myself, but I am most definitely a converted much Mochinut fan.

Nicola Twilley: Everything Q is delicious. Everything Q is good.

Nicola Twilley: Q rules. And this is, of course, an entirely objective conclusion. 

Cynthia Graber: Well, not necessarily. As we've heard from our listeners, not everyone likes the same textures, which probably means that somehow not everyone is experiencing textures the same way. Which leads me to wonder how in the world do you study it?

George Van Aken: Well, how would you measure it in the mouth [LAUGHS] 

Cynthia Graber: George Van Aken is a chemist who's been working in the food science industry in the Netherlands for about 30 years. He also specializes in food texture. 

Nicola Twilley: And this problem. This is why for a long time, no one really did try to measure it. But then in the 1950s, the newly emerged packaged food industry realized they needed to know what was going on texture wise in their foods.

George Van Aken: A lot of these products, they are crispy, and that's important for those products. And the industry has quite a lot of interest in that because if the product is expected to be crispy or the quality depends on it, then of course if it grows stale or whatever, yeah, people won't want to buy it.

Cynthia Graber: And so in the 1950s there was a scientist at General Foods who is looking into this. General Foods was a huge processed food company. They made cookies and cereals and Jell-O. They cared about texture. And so they tapped someone specifically to focus on it.

Bryony James:  And it really can be sheeted home to a food scientist called Elena Susan Yaki. Don't ask me to spell that. She was hiding behind the door when they were handing out vowels. And she started thinking about these ideas of food texture. And really, she's the mother of the field. And from that point forward, people realized that this was really important concepts that had been hidden before.

Nicola Twilley: Elena actually founded the scientific journal in the field, the Journal of Texture Studies, and her first big insight sounds really straightforward, but ended up being revolutionary. She pointed out the texture is sensory. It's experiential by definition.

Bryony James:  How do you quantify slimy? You know, so the human is the ultimate arbiter of texture.

Cynthia Graber: Elena basically created the definition of texture so that scientists could agree on what to study. The definition explains that texture is multifaceted and doesn't have one single descriptor that it needs a human to experience it, that it depends on the structure of food all the way down to the microscopic level, and that it involves several senses, not just touch. It's complicated. 

Nicola Twilley: But obviously scientists didn't respond to this complexity by just throwing their hands up in the air, having a Mochinut and calling it good. Instead, they set about figuring out what exactly was going on inside all those human mouths, where the experience of texture was being produced. 

Cynthia Graber: As we've explained, and unsurprisingly, this is hard to figure out and to model. It's one of the early tests researchers came up with, was something with a lovely name, a spit and chew test. They made test subjects, chew foods a certain amount of time and then spit it out. And they found that people are really different.

Kendra Pierre Louis: So like, no — not everyone chews food in the exact same pattern. One of the researchers they talked to like they had this crazy modeling that they also used for like the Australian swim team. And that was like one of their first reads. Yeah. 

[LAUGHING] 

Kendra Pierre Louis: Love looking into the mouth.

Cynthia Graber: Why was it the same model for the swim team? Was that like somebody moving through water is the same as food moving through your mouth?

Kendra Pierre Louis: I think so. And figuring out how your tongue moves versus how a swimmers body moves.

[LAUGHING] 

Nicola Twilley: Now I'm picturing me diving into a sea of mayo.

Cynthia Graber: And I'm picturing my tongue doing the the butterfly. 

[LAUGHING] 

Nicola Twilley: Hold those thoughts or not. But the other thing that is very bizarre about this is even though we're all different, where each always the same. 

Bryony James:  We are incredibly repeatable chewing machines individually. So if you take a large bite size of something, you are always going to take a large bite size of something. It makes some of our research questions somewhat challenging. When you know, you say somebody, well, take a bite of this biscuit, and the entire biscuit disappears. Oh, that was a bite. Right. So we are very, very repeatable within ourselves. But one to the other, we can be very different and very unique.

Cynthia Graber: We might be different and unique, but once again, scientists didn't give up. In recent years, they've been able to divide us into four basic groups.

Bryony James:  The four groupings they use would chewers, suckers, smooshers — chewers, suckers — and crunchers. Chewers, suckers, crunchers, and smooshers. There are other ways. You know, one of my great friends back in Auckland described tongue movements as — he described everybody as suckers, slappers or smooshes. So there's ways of describing people, but people tend to fall into groups.

Nicola Twilley: Oh, I am definitely not a sucker, but I might be a slapper, which is especially funny if you're British.'

Cynthia Graber: I'm pretty sure I'm a chewer. It doesn't matter what it is, I'm probably going to chew it.

Bryony James:  If I had two class myself, I'm a cruncher. Yeah.

Nicola Twilley: What kind of mouth behavior category you fall into is not just weird and interesting. It actually ends up affecting how your food tastes.

Bryony James:  The chewers, for example, when they were eating chocolate with menthol — with mint added, the chewers got this massively fast peak of a really high hit of menthol, but it went away really quickly. So of course, if you said to them, is that a minty chocolate at all? Yeah, that's just way too minty for me. Whereas exactly the same chocolate that when the suckers ate it, they got a far slower build of menthol. Never reached the very, very high high. But it went on longer. So if you liked mint chocolate, it was a more pleasurable experience because you didn't get that overpowering hit. So our mouth behaviors are tendency towards whether we like to chew things or suck things or crunch things or smoosh things with our tongue will have a lot of influence in the in the foods that we seek out and the foods that we consider pleasurable.

Cynthia Graber: This is really fun to try to figure out about yourself, but if you want to try to actually determine scientifically how texture influences whether, say, a particular food is pleasurable or not, these individual variations make the entire field super hard to study. 

Nicola Twilley: Because even though we all end up at the same place with the texture of food we can swallow, how we get there is all over the map.

Bryony James:  What you get is a lot of agreement at the start and a lot of agreement at the end. [LAUGHS] And then you get complete chaos in the middle. Everybody's taking their own route to get to their end point where some people are saying, oh, this is hard, start out hard. But now it's — oh, now it's really, really bitty and horrible. And some people are going, oh, it's getting smooth. Maybe somebody produces a lot of saliva, it's getting smooth really quickly. So you get this wonderful complexity in the middle thing, in the middle period between first bite and swallow that makes it a real pain in the ass to study, to be honest.

Nicola Twilley: But still, the scientists persisted. We've got the story of how they cracked the texture of problem and what they found after the break. 

Kenmjkli, my name is Jen. I'm from Toronto and I love the texture of stewed tendon. It's something that I grew up with eating at dim sum every weekend with my family. It kind of has a slimy, pasty texture that I think maybe some people think tastes kind of like fat, but I really like that mouthfeel.

Maddie: Hello, my name is Maddie Faust. I live in western Pennsylvania. The food that has the weirdest texture for me has got to be a banana. I love the taste of bananas. I even like the artificial banana flavor, like in a popsicle. But when I'm eating a straight up banana, I just can't get over that weird, slimy, squishy texture. It makes me gag every time.

Nicola Twilley: This was one of the big surprises of researching this episode. Who knew how many banana texture haters there are out there? So many of you turn out to think banana texture is an abomination. 

Cynthia Graber: I understand that an overripe bananas are a little much, but normal bananas? It's another example of how the way we all experience texture is so incredibly personal. 

Nicola Twilley: Personal experience aside, in the lab, a banana is just another food with a texture that is crying out to be objectively measured. George told us that in the past, scientists came up with a bunch of different devices to try to measure texture.

George Van Aken: People try to measure all these things outside of the mouth as an instrumental technique so we can use of force strength user, push all the products, call it the texture analyzer, see how large a force it becomes, if it peaks or not, if it's fractured or not in the texture analyzer.

Cynthia Graber: Scientists also tried rubbing food onto an instrument to try to figure out the texture.

George Van Aken: But then the question is, of course, what kind of services they'll use. People have tried — it's the stainless steel, but my mouth is usually not made of stainless steel unless you have a lot of fillings maybe. But it's no, basically it's not the same. You can use rubber, but rubber has completely different wetting properties and how hard should a rubber be? People use silicone probes. Also, not quite the same.

Nicola Twilley: People have even developed entire model tongues with little bobbly nubbles on them. Still not quite the same as real human tongue in a real human mouth. But George had an idea.

George Van Aken: Then I thought, well, if you can measure it instrumentally with a microphone, why not measure it in the mouth with a microphone?

Cynthia Graber: Because scientists had realized already that food makes sound of course. Chips make sound when you bite them. That experience is a big part of what we experience when we call something crunchy.

George Van Aken: So then I took a very small microphone and attached the to a tooth, the front tooth. Then you have the advantage that it's directly connected through the tooth with the jaws, and the jaws pick up a lot of signals of things that happen against the palate.

Nicola Twilley: Having a microphone on your tooth is a little awkward, honestly. So George played around with all kinds of places to put his microphone, and in the end he settled on placing it against the upper lip. And of course, he had to futz around a lot with the recordings to get rid of all the other sounds, the breathing and jaw clicks and people saying things.

Cynthia Graber: And then George had to take the resulting sound recordings and compare them to how people described the texture of the food they were eating. He needed to make sure that every time someone described something as creamy, those sound recordings also sounded similar, that there was a universal creamy sound. And actually, creamy was the first texture he used the setup to study. 

Nicola Twilley: Which was surprising to me because it's pretty easy to imagine what crunchy sounds like. But creaminess?

George Van Aken: Well, creamy shouldn't sound too much actually. Creamy sounds a lot softer, so it's a lot less sound. It's a very soft rubbing sound, but you don't hardly hear the rubbing itself.

Cynthia Graber: The food industry was interested in figuring out of George could measure creaminess. Imagine you want to do something like make a lower fat ice cream, but you still want it to be experienced as super creamy. How do you measure that without using a lot of people?

George Van Aken: And especially on the left scale, of course, if you develop a new product, you don't want to run to a sensory panel all the time because it's expensive.

Nicola Twilley: And George's system is sensitive enough to pick up small shades of creaminess. Like you can actually hear the difference in creaminess between plain black coffee versus coffee with cream in it. 

[SOUNDS OF CREAMINESS] 

Cynthia Graber: It's a subtle difference, but you can actually hear it. 

[SOUNDS OF CREAMINESS] 

Cynthia Graber: And George's system can analyze and recognize that difference, and.

George Van Aken: And that's quite a drastic difference. That was pretty obvious that it has to do with the lubrication caused by the cream that you add to the coffee. The feeling on your tongue is a lot more smooth.

Cynthia Graber: Okay, so George's new way of measuring cream and it's worked.

George Van Aken: I would say if you can sense the sensation, you taste different, different creaminess, I probably can measure it.

Cynthia Graber: But how about crunchy versus crispy? They're two different sensations. Could you tell the difference there? 

Nicola Twilley: I'm so glad you asked. Here's George's recording of a light crispy cookie. 

[RECORDING OF A LIGHT CRISPY COOKIE] 

Nicola Twilley: And this is a crunchy carrot.

[RECORDING OF A CRUNCHY CARROT] 

George Van Aken: Immediately, it tells you something about whether it's crispy or crunchy. Crunchy is usually in the lower frequency than crispy.

[RECORDING OF A CRUNCHY CARROT] 

Nicola Twilley: Again, it's subtle, but it's there. 

Cynthia Graber: As we said, industry is interested in this type of analysis. Like a company might want to know how long it'll take for their product to go stale. And they don't want to hire a lot of people to taste a lot of cookies at a lot of different stages.

George Van Aken: Yes, if cookies get stale, you can easily see it. So you can easily measure the speed by which it gets stale or that all kind of conditions of storage.

Nicola Twilley: George's method is a really promising technique to finally be able to measure and compare different levels of crunchiness, creaminess or crispiness. Meanwhile, Bryony has been wrestling with a different research problem how to figure out how the textures in food affect how we feel. 

Cynthia Graber: There had been some research that seemed to suggest that foods with lots of different textures helped people feel more full faster. Bryony wanted to figure out if it was the texture itself that had this effect or could it have been maybe the different flavors. But to get to the bottom of this, she and her students had to create a model of a food that had a lot of textures in it.

Bryony James: What Donny and Young created was these little models, they were based on gels. And then they created a whole bunch of different inserts that could go into these gels. So there was a little gluten flour disk that created a sort of a crisp texture. There were some sunflower seeds that were hard when you first encountered them with your teeth, but then broke down to give you bitty. They grind up some poppy seeds, which gave a real gritty texture on a agar disk gel, which was quite a — so there was a firm gel and a soft gel. Each little model was bite sized that made them a little slightly smaller than an ice cube. So the idea was that the participants could pop this into their mouth in one. They didn't have to take a bite of it. It was one mouthful. And as they chewed it up, all of these textures were released.

Nicola Twilley: Ultimately, as many as 27 different textures all crammed into one, otherwise pretty boring, very lightly lemon flavored gel cube. 

Cynthia Graber: The study of that complex texture had an impact on how much people ate. Bryony and her colleagues gave study participants a few cubes of texture gel as an appetizer.

Bryony James: They're in a controlled environment. They were in sensory booths to limit distractions. Then we gave them what's called an ad libitum meal. So ask for as many refills as you like guys. Go for your life. Pasta and tomato sauce and they chowed down. And the instruction was you keep eating and asking for refills until you cannot eat another bite. And that's what they did. Ate and ate and ate and they could not eat another bite. They said, yeah, I'm absolutely full, absolutely full. And then we offered them chocolate cake. And without fail, everybody asked for more chocolate cake. So he dessert stomach is a real thing. That was one of our findings.

Nicola Twilley: Finally, science proves something I already knew. But the other super interesting finding was that, yes, people who had more multi texture snacks before their meal ate less.

Bryony James: And what we found was that there was no conscious effect of this. At no point did the people who had preloaded on the high textural complexity think they felt fuller. So this was a totally subconscious reaction to the textural complexity, leading them to eat less without them feeling more or less full. So, that I think, it was a very, very promising finding because when you want to manipulate how much people eat, then you don't want them to feel hungry because what's the point then?

Cynthia Graber: Bryony's passed this particular study onto some colleagues who are now trying to tease out the why of it. They have some ideas. Are there hormones that the textures kick off that signal feeling full?

Nicola Twilley: Or is the texture interacting with your brain in a different way to convince it that it must have had a bunch of great food because it's experienced all these textures? Like, wow, I must have eaten a ton to have had grittiness and crunchiness and creaminess. 

Cynthia Graber: That research is still going on, but the larger point is studying texture isn't just about keeping processed food companies in business or even just about teasing out the weirdness of our individual preferences. It's got real world benefits.

Bryony James: The reason I'm excited about this is if you think at both ends of the age scale, very, very young children, they need to chew things. They need to chew things to develop good dentition and yet what's safe is soft pureed foods.

Cynthia Graber: Nobody wants their kid to choke, but kids need to chew to learn how to eat and to actually build a healthy jaw.

Bryony James: So there's got to be an answer there that allows busy parents to safely feed their kids while still allowing them to develop really healthy nutrition that sets them up for a healthy life.

Nicola Twilley: The same sorts of texture innovations could really help at the other end of the spectrum, too.

Bryony James: Because of course, as people get older, their bite force goes down, their salivary flow rates go down and you see older people making food choices that are dictated more by what's safe and comfortable than by what they like, which is very sad. And then if you factor in things like dysphagia, swallowing difficulties and xerostomia, which is dry mouth, you factor all these terrible things that happen to us as we get older, and the food choices of people in their twilight years can get really limited. And if you think about the importance of the social interactions of food, that's a huge tragedy, right? But if you could design a food that to your eye would go like, oh, that's a bit soft and insipid. But to my parents that, oh, that's lovely and crispy, that's crunchy, that's like eating a lovely green apple, but was still safe for them, still broke down comfortably, that's a line of research that I know many people are pursuing because I think the end point of that is actually just improve quality of life for a whole bunch of people.

Cynthia Graber: Another way this texture research has fairly immediate applications has to do with COVID. You listeners probably know that one result from COVID can be a loss of smell.

Ole Mouritsen: And then if you cranked up texture, you can actually sort of recover at least some of the experiences that you have lost by taste and flavor.

Nicola Twilley: The science behind this trick, the idea that you can get back some of the sensory experience of taste and flavor by actually boosting texture that turns out to be the motivation behind one of the world's most iconic ice cream brands.

Kendra Pierre Louis: So before Ben and Jerry's, ice cream for the most part, was smooth. And I feel like the best example of this is Haagen-Dazs makes an ice cream called Vanilla Swiss Almond. And there's like one almond per scoop. I mean, I'm exaggerating, but they're — the almond to ice cream ratio is not huge. And what Ben and Jerry's did was like, they're like, we're going to dump 9 pounds of almonds in here. Right? Like, they made their their ice creams super, super, super chunky. And so every scoop, every bite was like a new experience.

Cynthia Graber: An incredibly delicious experience that revolutionized my high school and college years. But it turns out that it's all thanks to Ben Cohen, one of the founders. He had a sinus condition that led to anosmia, which meant that he had a really limited sense of smell and so he couldn't taste food well. 

Kendra Pierre Louis: So for him, ice cream doesn't have much flavor, but adding a bunch of chunks to it makes it a really lovely sensory experience.

Nicola Twilley: I feel like Ben Jerry's has a lesson for us all here, which is that we should embrace texture in all its many splendid variety because texture is truly part of the joy of eating. That's how our Q food adventure guide Cathy feels.

Cathy Erway: Sometimes I hear folks describe like the texture of tofu as sort of unappetizing or blubbery, or sometimes I hear folks describe something as gummy, being like sort of an off texture. And if we don't think of these things as off textures, it's just kind of like, you know, need to rewire your brain a little bit. You can just delight in them so much.

Nicola Twilley: I kind of want to take back my harsh words about okra and tripe, but not Miracle Whip. That's still gross. 

Cynthia Graber: A lot of you have strong feelings about different textures, and certainly entire cultures have strong feelings about different textures. But if we focus on them as a new and interesting mouthfeel experience in our lives, maybe we can just be open to them as a different way to enjoy our food.

Cathy Erway: Clearly, you know, it's not like biological. Like we can all appreciate different things if we maybe just celebrate them a little bit more and don't, you know, look down upon them.

MUSIC

Nicola Twilley: A lot of you shared your texture, thoughts and feelings with us for this episode, which made for super fun listening. Thank you. 

Cynthia Graber: But there's one texture issue that came up that we wanted to come back to. It's one that a couple of autistic listeners pointed out.

Christy: I wish people knew that it's not a choice and it's never something that we're doing to just kind of be a problem or to be a diva, as I got called a lot.

Cynthia Graber: In fact, another listener named Catherine Karsner wrote in to tell us that she's a registered dietitian who works with people who have what's called ARFID or avoidant restrictive food intake disorder.

Catherine Karsner: So people who have autism spectrum conditions or ADHD are more susceptible.

Nicola Twilley: One of the common symptoms of ARFID is a hypersensitivity to food texture. Catherine told us she has a variety of techniques to help someone who struggles with food for texture reasons. Like for example, our banana haters.

Catherine Karsner: We might start with a fruit mix or a fruit smoothie that the person has previously, you know, accepted very well and can tolerate. And then bit by bit incorporate the banana. And then we may try banana in different contexts or in different foods. So say, if we're just trying the raw banana or cooked in a bread or a cake.

Cynthia Graber: She says, you can try this at home. You can start by slowly touching and smelling foods you have an aversion to and work up to incorporating tiny tastes. We'll have more about ARFID and how Catherine helps people deal with food texture aversions in our Special Supporters newsletter, Gastropub.com/support. 

Nicola Twilley: Thanks. This episode to you all for writing and calling in and to our superstar producer Claudia Guibert, pulling it all together. 

Cynthia Graber: Thanks also to all our guests this episode Kendra Pierre Lewis, Ole Mouritsern, George Van Aitken and Bryony James. We have links to their articles, books and research at Gastro podcast.

Nicola Twilley: We'll be back in a couple of weeks. Stay tuned. 

MUSIC

Dan Pashman: That’s Cynthia Graber and Nicola Twilley, the hosts of Gastropod. It’s a podcast about food through the lens of science and history. If you like The Sporkful, you're gonna love Gastropod Some of their other recent episodes include the wild history of Coca-Cola, and the story of a fruit that just might be able to save the world. Check it out wherever you got this podcast.

Dan Pashman: Next week’s show, I head to Alameda, California, and meet up with cookbook author and recipe developer Andrea Nguyen. She’s made it her mission to demystify Asian cooking without dumbing it down. But as she concedes, that’s easier said than done. She’ll explain her approach, and we will eat! Andrea took me to a modern Vietnamese restaurant in Alameda, California that she’s been dying to go to and we feasted. You gotta hear this. We had a ton of fun. That's next week.

Dan Pashman: And don’t forget to stock up on all my pastas ahead of Mother's and Father's Day. Get them at Sfoglini.com and check out last week’s show, featuring the one and only, Bill Nye.