This is a transcript of the Gastropod episode, All the Feels: How Texture Makes Taste, first released on April 11, 2023. It is provided as a courtesy and may contain errors.
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? And with mayo in parti—
CYNTHIA GRABER: Because it’s delicious. Go on.
NICOLA TWILLEY: No! I don’t think it should exist either.
PIERRE-LOUIS: I literally just shivered. Sorry.
GRABER: We called up Kendra Pierre-Louis not because she’s an amazing climate reporter, which she is, but because she is also very public about her very strong feelings about food texture. And because she has such strong feelings about texture, she’s done what science journalists do and written a bunch of articles about it.
PIERRE-LOUIS: I probably should have introduced myself as, my name is Kendra Pierre-Louis, and I’m the author of the story, “Mayonnaise is Disgusting and Science Agrees.” 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 off a website.
TWILLEY: Big Mayo tried to take you down.
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 any more. That said, it is an extremely hated food.
PIERRE-LOUIS: 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 sizable 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.
TWILLEY: That’s me! I’ve given up, folks! It’s more applicable than you know.
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.
CATHY ERWAY: Just a little too… much. [LAUGHS] Like a little too, ooh. Like intimate or something. I don’t know. I don’t know how to describe it. [LAUGHS]
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, Gastropod, 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.
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.
TWILLEY: Stringiness is a real problem for me.
GRABER: Spaghetti squash should be thrown out the window. Like why do people, and why do people think it’s pasta? The texture is ridiculous. And it doesn’t taste like anything.
PIERRE-LOUIS: That’s why it’s good though! Because well I actually do like the texture, but also the reason it does that, it, it’s good, is that it doesn’t taste like anything. So it’s one of those things you can throw in anything. And be like, oh, I got my veggie for the day.
GRABER: Mm. I guess. I just, I love vegetables so much and I, that’s a texture I actually don’t like.
TWILLEY: Yeah. Stringiness is kind of repulsive, I’m with you there.
PIERRE-LOUIS: So much judgment.
TWILLEY: Oh yeah. And no shame about it.
GRABER: Not at all.
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?
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?
TWILLEY: Plus, do all cuisines and cultures prize the same textures or is there a whole textural universe out there to explore?
GRABER: This episode is made possible in part by the Burroughs Wellcome Fund, in support of our coverage of biomedical research, and by the Alfred P. Sloan Foundation for the Public Understanding of Science, Technology and Economics. Gastropod is part of the Vox Media Podcast Network, in partnership with Eater.
MATTHEW MCMASTERS: Hi, Gastropod. I’m Matt and I’m from London, and I love the texture of caviar. There’s something about the… the way when you slowly chew it, 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 SCHNEIDER: 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 kinda kicks back in and it just freaks me out.
GRABER: A pop and a squish! One person hates it, another can’t get enough.
TWILLEY: Horses for courses, as we’d say in the UK: 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 mouth coating. A lot of people when they’re eating ice cream will go, oh, it’s, it’s coating my mouth.
GEORGE VAN AKEN: It’s, greasiness, crispiness, smoothness. Thickness. Hardness.
PIERRE-LOUIS: Creamy and crispy and crunchy. How do people talk about cake a lot? Like… fluffy?
OLE MOURITSEN: Hard or chewy or mealy or dry. Squishy, oily.
VAN AKEN: All these kind of experiences that you can have are typically oral sensations that are basically, really felt in the mouth.
TWILLEY: So texture is just a whole bunch of different mouth feelings.
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.
JAMES: But if you say, you know, does this steak, 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 the bits of food that are critically important to how much we enjoy it, but possibly people don’t always articulate them as texture.
TWILLEY: Bryony James is a professor at the University of Waikato in New Zealand, and she studies food texture.
GRABER: A lot of different things are going on in our mouths at the same time that all combine into this thing we call texture.
JAMES: Your teeth are obviously registering pressure, and that will be translated into a perception of, of a hard texture.
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.
GRABER: One way to think about these receptors in our mouth is like the springs on a mattress.
MOURITSEN: And if you, you sit on the mattress, the springs will deform and if springs deform, the mattress will deform. So it’s a coupled 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.
GRABER: One more texture expert to meet, this is Ole Mouristen, 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.
MOURITSEN: If you have an ice cream that is completely smooth, you don’t feel any particles in the, 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.
TWILLEY: Astonishingly our tongues are pretty much as sensitive as fingertips in terms of how accurately they can gauge particle size.
JAMES: You’re going to detect particles that are bigger than about 35 microns, and that will convey a gritty texture. So it’d give you context of that: the hair on your head is between 50 and a hundred microns, so something about a third of the width of one of the hairs on your head, your tongue will go, oh, there’s a, there’s a particle. And if there’s lots of that, you’ll get a gritty, often quite unpleasant sensation.
GRABER: Most of us prefer our 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. But speaking of creamy – how do we sense it? I mean, it’s not just the absence of grittiness. Or is it?
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 we, you know, we’re certainly closing in on this. Creaminess has a lot to do with particle size. So the smaller the particles, the creamier.
TWILLEY: So yes, one of the things going on in a 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 mouths, they’re also feeling how the food flows over the tongue, how viscous it is. Viscosity seems to be another key element of creaminess.
JAMES: But also there’s, there’s a, a fairly strong body of evidence that the body is extremely sensitive to, the presence of fat, say. So. So even if it’s concealed in other things, your, your brain goes, oh, there’s a, there’s a fat molecule there. And that can also contribute to the textual perception of creaminess.
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.
JAMES: So if you think of something like a really soft caramel or, or toffee—or caramel as Americans pronounce it. [LAUGHS] If you, if you chew down on that, then of course you think about pulling your teeth apart. It’s now pulling on the mechanoreceptors. So the 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.
TWILLEY: These mattress spring receptors are in your teeth and also your gums and when something is chewy they’re being stretched *and* compressed.
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.
TWILLEY: So you’re feeling texture through these receptors in your mouth, which are super sensitive, you’re sensing texture though sound, too. And then it turns out you’re even sensing texture outside your body, before the food even gets to your lips.
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.
PIERRE-LOUIS: And if you’re holding onto the stale end and you’re biting into the fresh piece, you will taste that fresh piece as stale. And if you flip it so you’re holding onto the fresh piece, but you’re biting into the stale end, you will, you will think that that piece is fresher than it actually is.
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.
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 makes the connection between those sensations, and it creates our sense of what the texture of that food is.
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.
GRABER: For both animals and plants, that inherent texture has to do with the structure and make-up 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.
MOURITSEN: I mean, think of having an apple which is overripe, and you bite in this overripe apple, and then you say, well, it tastes mealy, which of course not a taste, it’s a sensation and it’s, it’s dry.
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.
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.
MOURITSEN: So if you take land animals, our, our muscular structure is, is very much a consequence of the fact that we constantly have to work against gravity.
TWILLEY: It makes me tired just thinking of it. But then picture floating in the ocean like a fish—like sure, you have to swim, but you’re all buoyed up and supported against the drag of gravity by the water.
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, take a piece of salmon or tuna or other fish, most people have probably wondered how come this fish can be so strong and a furious fighter? But I can, I can take the, the muscle and I can poke my finger right through it.
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.
TWILLEY: Until you cook them. When you think about it, one of the main things that is going on when we cook stuff is we’re changing its texture.
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.
TWILLEY: So far, we’ve 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.
JAMES: Almost all foods will release a multiple series of textures, and also they change with time. Very, very dynamic thing to study.
GRABER: As an example, Bryony introduced me to a cookie I’d never heard of before, it’s called the ginger nut.
TWILLEY: Ginger nut is also slang for a redhead in the UK, 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.
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 it in their tea. They’re the classic dunking biscuit. So, 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, and the particles get smaller and smaller. They maintain their 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.
TWILLEY: And then, with a sigh of relief, they vow *never* to eat a ginger nut again.
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 in it from right 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.
TWILLEY: This makes Bryony’s and Ole’s 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.
MOURITSEN: So…it is a mess if you, if you allow me to say so. There are many different things that happen at the same time.
GRABER: And what’s wild is that each of those sensations can each influence each other. Texture can actually influence flavor and vice versa.
MOURITSEN: The most well known example with, with texture, that is vanilla. That people, if you have vanilla in some food it, you perceive it as more creamy than without vanilla. There’s something you can easily test yourself.
TWILLEY: It’s weird but true. One theory is that this is just a learned connection, that we’re so used at least in the West, to vanilla custards and vanilla ice creams and vanilla yogurts that we just make that creamy vanilla connection.
MOURITSEN: But there’s no physiological mechanism that dictates that these should be related. The vanilla vanillin that gives the flavor of vanilla has nothing to do with creaminess. So it’s, it’s, it’s all connections in the brain.
JAMES: So, 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 are used to thinking about taste. We’re used to talking about flavor and smell. So the texture one might be the hidden one, but it’s contributing to all the others.
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.
JAMES: I can give you any number of examples of that, but possibly the simplest one to start with would be chocolate. So, so you’ll, you, if you leave chocolate lying around a bit, you know, it gets that white bloom on the surface. And, and if you read the packet of a, you know, packet, chocolate biscuits, it says, don’t worry about this, it won’t affect the flavor whatsoever. And actually that’s true and not true at the same time. So, 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—more like a wax candle, really, it doesn’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.
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.
MOURITSEN: You have to make sure that all these wonderful things that gives you the pleasure, they’re 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, they’re not supposed to be released actually so quickly that you can’t perceive them before it’s all over.
TWILLEY: Imagine you had a Starburst that was 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 gave us 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.
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.
KRISTI HAYHOW: Hey, Gastropod. This is Kristi 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 MICKEY: This is Hollis from Anchorage, Alaska. I used to love hotdogs. 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.
BENJAMIN CLAXTON-STEVENS: I didn’t used 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.
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…
PIERRE-LOUIS: My favorite food as a kid was tripe. I called it rubber meat.
GRABER: In case you haven’t heard of it before, tripe is the food word for cooked intestines.
PIERRE-LOUIS: And whenever my mom cooked it, I would like, go to town. And I think—
GRABER: [LAUGHS] I love this.
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?
TWILLEY: Oh my god all of those things are disgusting to me. Miracle whip, tripe, and okra, no way, nuh uh, no thank you! Which just goes to show that individual eaters definitely have their own individual texture preferences.
GRABER: And it’s not just individual eaters. Entire cultures come with textural preferences.
JAMES: So different cultures have different lists of words and different ways of expressing texture. And, and crisp and crunchy, depending on your culture, are, are seen as very desirable textures. But then other cultures prefer soft and slimy. Now, if you say slimy to, to someone who speaks English or American English, they go, Ooh, that doesn’t sound very nice. But when it’s translated into, into Japanese or Chinese, it’s a very desirable texture.
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.
JAMES: They’ve got over 400 words, 400 unique words for different food textures.
MOURITSEN: I, I sort of ask myself, how come that the Japanese are very fascinated with seaweeds that have very mild flavors? It’s not something very strong like a spice. But it’s mouth feel. That this fact, you have to appreciate the particular tactile sensation of the different kinds of seaweed when you, when you chew on them.
GRABER: In general, Eastern languages have words for textures that we don’t really focus on in the West. Cathy Erway is the author of the cookbook The Food of Taiwan, and she told us Taiwanese love a texture called Q.
ERWAY: Anything that is springy, bouncy, a little chewy. You know, a lot of people know mochi. That is a great Q texture. Classic.
TWILLEY: Mochi is delicious. If you haven’t had it before it’s like a squidgy blob made out of rice flour. To me its always kind of felt like a slightly softer, Japanese version of gummy candy.
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 in to bite.
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’s not the only place to find Q.
ERWAY: Tapioca pearls, you’ll find in boba tea. That’s another classic Q texture. I, I think also fish balls that are enjoyed in like, East Asia, have that bounciness to them.
TWILLEY: This springy, chewy, bouncy texture is always written using just the letter Q, even in the middle of a sentence that is otherwise entirely written in Chinese characters. Which is weird, because Q as a texture isn’t a Western concept.
ERWAY: This was like a term that was really popularized in Taiwan in more contemporary times. And it, it derives from a Taiwanese or Hokkien-derived term, which is Q, it sounds like Q. But nowadays it’s always spelled with just the Roman [LAUGHS] letter Q.
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?
ERWAY: I mean, I would say rubbery, but like in a good way. [LAUGHS] No negative connotations whatsoever.
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 am 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.
ERWAY: This is Mochinut. It specializes in mochi donuts, which is kind of like the best of both worlds.
GRABER: I’m pretty obsessed with mochi, and I’ve had doughnuts, but I had never enjoyed the special treat that is a Mochinut. I was pretty excited.
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 different Q-like jelly called aiyu jelly, which is made from a seed.
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 it maybe had some Q.
TWILLEY: What about that? It is like, incredible. It is a crispy potato crusted, crispy thing.
GRABER: But there’s like, it, it little pieces of potato. So you have, it’s like this little knobbly, like lots of little potato bits fried onto something else.
TWILLEY: This non-hot 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.
ERWAY: Maybe you could rip off a piece.
GRABER: I can try to rip off a piece.
[CRUNCHY, CRACKLING TEARING]
GRABER: Oh my goodness.
ERWAY: Oh, wow.
ERWAY: Okay. That’s like all the textures in one. Okay.
GRABER: Weirdly, it’s a little sweet, too. I feel like there’s…
ERWAY: Yeah, I think it might be the mochi donut that is just, you know, on the outside of this cheese blob.
TWILLEY: Extremely intriguing. We washed this mochi potato cheese stick thing down with our Q filled teas.
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.
TWILLEY: Yeah. Yeah. The, the aiyu jelly almost slithers down with the rest of the tea, right?
ERWAY: It does.
GRABER: And then we moved on to the main event, the mochi doughnuts. Or mochinuts.
TWILLEY: So excited. It looks light, fluffy, everything perfect..
ERWAY: These are good. Mm-hmm.
GRABER: So this is my first mochi donut. And I’ve already said I’m obsessed with mochi. It has so much more springiness to it than other donuts. Like the… it’s just got this like, bounciness one might call it. Maybe a little bit of Q even?
ERWAY: It’s like a completely… slightly, you know, more elastic donut than, 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 chew.
GRABER: I’m not going to turn down a regular doughnut myself, but I am most definitely a converted Mochinut fan.
TWILLEY: Everything Q is delicious.
ERWAY: Everything Q is good.
TWILLEY: Q rules. And this is of course an entirely objective conclusion.
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?!
VAN AKEN: Well, how would you measure it in the mouth? [LAUGHS]
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.
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.
VAN AKEN: A lot of these products, they’re crispy and it’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 goes stale or whatever, people won’t want to buy it.
GRABER: And so in the 1950s there was a scientist at General Foods who was 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.
JAMES: And it really can be sheeted home to a food scientist called Alina Szczesniak. 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 realize that these were these really important concepts that had been hidden before.
TWILLEY: Alina 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 that texture is sensory. It’s experiential, by definition.
JAMES: How do you quantify slimy, you know? The human is the ultimate arbiter of texture.
GRABER: Alina 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.
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.
GRABER: As we’ve explained, and unsurprisingly, this is hard to figure out and to model. So 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 out that people are really different.
PIERRE-LOUIS: So like, no, not everyone chews food in the exact same pattern. One of the researchers I talked to, like, they had this like crazy modeling that they also used for like, the Australian swim team? And that was like one of their first ways— [LAUGHS] yeah, of looking into the mouth.
GRABER: Why was it the same model for the swim team, were they, was that like somebody moving through water is the same as food moving through your mouth?
PIERRE-LOUIS: I think so. And figuring out like, how your tongue moves versus how a swimmer’s body moves.
TWILLEY: Now I’m picturing, me diving into a sea of mayo!
GRABER: And I’m picturing my tongue doing the butterfly.
TWILLEY: Um, hold those thoughts. Or not. But the other thing that is very bizarre about this is even though we’re all different, we’re each always the same.
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, it makes some of our research questions somewhat challenging, when, you know, you say to somebody, well take a bite of this biscuit, and the entire biscuit disappears. [LAUGHS] 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.
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:
JAMES: The four groupings they use were chewers, suckers, smooshers… chewers, suckers… and crunchers. Chewers, suckers, crunchers and smooshers. There are other ways you, one of my great friends back in Auckland, described tongue movements as—he described everybody as suckers, slappers, or smooshers. So there’s, there’s ways of describing people. But people tend to fall into groups
TWILLEY: Ooh, I am definitely not a sucker. But I might be a slapper. Which is especially funny if you’re British.
GRABER: I’m pretty sure I’m a chewer. Doesn’t matter what it is, I’m probably going to chew it.
JAMES: I, I’m, I’m a, if I had to classify myself, I’m a cruncher. Yeah.
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: The chewers, for example, when they were looking at, 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’d said to them, is that a minty chocolate? They’d gone, oh yeah, that’s just way too minty for me. Whereas exactly the same chocolate that the, 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, so our, our mouth behaviors, our 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.
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.
TWILLEY: Because even though we all end up at the same place—with a texture of food that we can swallow—how we get there is all over the map.
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, started out hard, but, 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, so you get this wonderful complexity in the middle thing, in the middle period between first bite and, and swallow. That makes it a royal pain in the ass to study, to be honest.
TWILLEY: But still, the scientists persisted. We’ve got the story of how they cracked the texture problem, and what they found, after the break.
KENDRA GAHAGAN: I’m Kendra in Boston, and for some reason I just can’t bring myself to like or eat shrimp. I’ve tried my whole life, and the texture is so sinewy and tough. It makes me think of what it might be like to chomp into someone’s index finger, which I’m not sure why, but. Never got over that, and still don’t like shrimp.
JENNIFER YEUNG: Hi, 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 mouth feel.
MADDI FOUST: Hello, my name is Maddi Foust. 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.
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!
GRABER: I understand that an overripe banana is a little much, but normal bananas? It’s another example of how the way we all experience texture is so incredibly personal.
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.
VAN AKEN: People try to measure all these things outside of the mouth. There’s an instrumental technique. So we can use a force transducer. Push on a product. They call it a texture analyzer. See how large the force becomes, if it peaks or not, if it fractures or not, in the texture analyzer.
GRABER: Scientists also tried rubbing food onto an instrument to try to figure out the texture.
VAN AKEN: But then the question is, of course, what kind of surfaces do I use? People have tried 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 the rubber be? People use silicon probes. Also not quite the same.
TWILLEY: People have even developed entire model tongues with little bobbly nubbles on them. Still not quite the same as a real human tongue in a real human mouth. But George had an idea.
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?
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.
VAN AKEN: So then I took a very small microphone and attached it 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.
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.
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 this setup to study.
TWILLEY: Which was surprising to me because it’s pretty easy to imagine what crunchy sounds like, but creaminess?
VAN AKEN: Well creaminess shouldn’t sound too much actually. Creamy sounds a lot softer, so it’s a lot less sound. It’s, it’s, it’s very soft. Soft rubbing sound, but you don’t hardly hear the rubbing itself.
GRABER: The food industry was interested in figuring out if 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?
VAN AKEN: And especially on the lab scale, of course, if you develop a new product, you don’t want to run to a sensory panel all the time cause it’s expensive.
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—
[HIGH PITCHED RUBBING, BRUSHING SOUND]
TWILLEY: —versus coffee with cream it in.
[LOWER-PITCHED, SOFTER RUBBING]
GRABER: It’s a subtle difference, but you can actually hear it—
[BLACK COFFEE SOUND, THEN CREAMY COFFEE SOUND]
GRABER: —and George’s system can analyze and recognize that difference.
VAN AKEN: And that’s quite a drastic difference. And 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..
GRABER: Okay, so George’s new way of measuring creaminess worked.
VAN AKEN: I would say if you can sense the sensation, you taste a different in creaminess, I probably can measure it.
GRABER: But how about crunchy versus crispy? They’re two different sensations. Could he tell the difference there?
TWILLEY: I’m so glad you asked! Here’s George’s recording of a light crispy cookie:
TWILLEY: And this is a crunchy carrot.
[LOWER PITCHED, LOUDER CRUNCHING]
VAN AKEN: It immediately tells you something about whether it’s crispy or crunchy. Crunchy is usually at a lower frequency than crispy.
[LOW-PITCHED CRUNCHY, THEN HIGH-PITCHED CRISPY]
TWILLEY: Again, it’s subtle, but it’s there.
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.
VAN AKEN: Yes. If if, if cookies get stale, you can easily see it. So you can easily measure the speed by which it gets stale with all kind of conditions of storage.
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 texture research problem: how to figure out how the textures in food affect how we feel.
GRABER: There’d 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 that 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.
JAMES: What Danny and Ying created was this, these, 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 disc that, that created a sort of 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 ground up some poppy seeds, which gave a real gritty texture. Oh, and an agar disc gel, which was quite a firm—so there was a firm gel and a soft gel. Each little model was bite sized. They made ’em in 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.
TWILLEY: Ultimately, as many as 27 different textures, all crammed into one otherwise pretty boring, very lightly lemon-flavored gel cube.
GRABER: To study if that complex texture had an impact on how much people ate, Bryony and her colleagues gave study participants a few cubes of textured gel as an appetizer.
JAMES: They’re in a controlled environment, they’re 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’d 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. They ate and ate and ate and they could not eat another bite. And they said, yep, absolutely full, absolutely full. And then we offered them chocolate cake. And without fail, everybody asked for more chocolate cake. So, so the dessert stomach is a real thing. That was one of our findings.
TWILLEY: Finally science proves something I already knew. But the other super interesting finding was that yes, people who had had more multitexture snacks before their meal ate less.
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 textual complexity think they felt fuller. So this was a totally subconscious reaction to the textual complexity, leading them to eat less, without them feeling more or less full. So, so that I think was a very, very promising finding. Cause when you want to manipulate how much people eat, then you don’t want them to feel hungry. Cause what’s the point then?
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?
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.
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.
JAMES: And 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.
GRABER: Nobody wants their kid to choke, but kids need to chew, to learn how to eat and to actually build a healthy jaw.
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.
TWILLEY: The same sorts of texture innovations could really help at the other end of the age spectrum, too
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, you factor all these terrible things that happen to us as we get older, and… The food choices of people, in their, 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, that’s a bit soft and insipid. But to my parents, they go, 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, the end point of that is actually just improved quality of life for a whole bunch of people.
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.
MOURITSEN: And then if you crank up texture, you can actually sort of recover at least some of the experiences that you have lost by taste and flavor.
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.
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 their, the almond to ice cream ratio is not huge. And what Ben and Jerry’s did was like, they were like, we’re going to dump nine 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.
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 he had a really limited sense of smell and so he couldn’t taste food well.
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.
TWILLEY: I feel like Ben and Jerry’s has a lesson for us all here, which is that we should embrace texture and its all many-splendored variety, because texture is truly part of the joy of eating. That’s how our Q food adventure guide, Cathy, feels.
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, [LAUGHS] it’s just you kind of like, you know, you need to rewire your brain a little bit. You can just delight in them so much.
TWILLEY: I kind of want to take back my harsh words about okra and tripe! But not miracle whip, that’s still gross.
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.
ERWAY: Clearly, you know, it’s not like, biological, like. [LAUGHS] 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.
TWILLEY: A lot of you shared your texture thoughts and feelings with us for this episode, which made for super fun listening—thank you! 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.
HAYHOW: 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.
GRABER: In fact, another listener named Katheryn Kastner wrote in to tell us that she’s a registered dietician who works with people who have what’s called ARFID, or Avoidant Restrictive Food Intake Disorder.
KATHERYN KASTNER: So people who have autism spectrum conditions or ADHD are more susceptible.
TWILLEY: One of the common symptoms of ARFID is a hypersensitivity to food *texture.* Katheryn told us she has a variety of techniques to help someone who struggles with food for texture reasons, like for example our banana haters.
KASTNER: 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, a cake.
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 Katheryn helps people deal with food texture aversions in our special supporters’ newsletter, gastropod.com slash support.
TWILLEY: Thanks this episode to you all, for writing and calling in, and to our superstar producer Claudia Geib, for pulling it all together.
GRABER: Thanks also to all our guests this episode: Kendra Pierre-Louis, Ole Mouristen, George Van Aken, Cathy Erway, and Bryony James. We have links to their articles, books, and research at gastropod.com.
TWILLEY: We’ll be back in a couple of weeks, stay tuned!