The Current - The molecular approach to great-tasting food

Episode Date: October 14, 2024

Arielle Johnson says knowing the basic building blocks of taste — on a molecular level — can help any cook create something delicious. In a conversation from May, she talks to Matt Galloway about the science of flavour and her book, Flavorama. 

In 2017, it felt like drugs were everywhere in the news, so I started a podcast called On Drugs. We covered a lot of ground over two seasons, but there are still so many more stories to tell. I'm Jeff Turner, and I'm back with Season 3 of On Drugs. And this time, it's going to get personal. I don't know who Sober Jeff is. I don't even know if I like that guy.

On Drugs is available now wherever you get your podcasts. This is a CBC Podcast. Hello, I'm Matt Galloway, and this is The Current Podcast. When it comes to cooking, most of us instinctively know it's all about flavor. This is a really classic Italian vegetable. And strangely, isn't even related to broccoli. But it's got great flavor,

a little more bitter. Flavor in there. I'm going to add a little fish sauce. Don't be afraid of fish sauce. People think, oh, it's going to taste fishy. It just gives you

a little bit of umami. Umami is the flavor that makes your mouth water. And it's prevalent in so many different... ...using passion fruit, just scooping them out, because the sourness, the aromatic sourness of the passion fruit works so well against the sugary sweetness of the meringue. There's salty, sweet, bitter, sour, umami. Those are the building blocks, a big part of why food tastes the way it does.

But Arielle Johnson argues there is much more to it than that. She is a flavor scientist. She's worked with some of the world's top chefs. And in her new book, Flavorama, she argues that learning more about the science of flavor can actually help all of us make tastier food. I spoke with Arielle Johnson in May. Here is our conversation. Let's start with the beginning.

How is knowing more about the science of flavor going to make me a better cook? Well, I think understanding the science of flavor is really understanding, you know, how food works, kind of if you look under the hood, it's kind of like x-ray vision. I liken it to the difference between only being able to follow your turn-by-turn GPS on your phone versus understanding your city well enough that you can find your way around without a map. You say in the book that flavor is not ineffable vibes or an abstract quality that imbues lemons with lemoniness. That's true. I mean, I know it sounds silly to put it that way,

but I think that is how, absent any other information, a lot of people tend to think about it. But yeah, no, the fact is, is that flavor comes from molecules. There is science to this. Absolutely. Why did you want to get involved in this? I mean, take us back to the beginning for you. How did you get interested in the science of flavor? flavor? Well, I mean, I was always interested in science and encouraged to be interested in it, but also creative things. My grandmother was a fantastic cook, and I used to go to her house and after making a cursory hello, kind of pull the best cookbooks off her bookshelf and sit and read with them for a few hours. And as a child, I loved intense smells and flavors. I loved the smell of fresh coffee grounds and even gasoline. My favorite flavor combination at the ice cream store was orange sherbet and Reese's peanut butter cups.

Eventually, I got to college and I was doing a chemistry degree and found some people there, one of my chemistry professors that was also really into food. And found some people there, one of my chemistry professors that was also really into food, and he was starting a group called the Experimental Cuisine Collective of sort of like-minded people from chemistry and food studies and even chefs downtown in New York. And, you know, as I started hanging out with them, it was pretty clear that this was the exact right synthesis of what I wanted to do. So I ended up going to UC Davis in Northern California and was in their wine department for five years for my PhD. And then kind of move on from there. Yeah, yeah. There's a story that I had heard. It involves ants from Brazil or something like that? What is this ant story?

So people all over the world eat insects. It's a commonplace thing. In the West, chefs have kind of gotten more intrigued with it in the last 10, 15 years. So, you know, in addition to being a graduate student, a scientist like that, I was also collaborating with restaurants at the time. So I was in Copenhagen working with restaurant Noma at a little houseboat that they had anchored outside of the restaurant that they called the Nordic Food Lab. This is generally considered to be the best restaurant in the world. Yeah, yeah. It does often win that award. It's true. But yeah, so a restaurant like that, perhaps it is not surprising, can have a research lab attached to it. And the chefs were interested in edible insects, not just as a protein source, but for flavor and for, you know, exciting culinary experiences and had been kind of

looking through, you know, the academic literature to try to find information about this. And there was really nothing about the deliciousness of eating insects, but they did find some entomology papers that had to do with chemical communication between ants. So ants, you know, they don't speak. They actually communicate with different smell molecules, weirdly enough. And I just looked over their shoulder one day and saw what they were looking at and said, oh, why are you reading up about lemongrass? And he's like, I'm not reading about lemongrass. I'm reading about ants. And I said, well, that's the molecule that's in lemongrass that makes lemongrass smell like lemongrass. And that one smells like basil and that one smells like leather. And yeah, it turns out that because of entomology, not any sort of flavor research, we actually do have a lot of data about ant flavors and that ants produce a lot of the same flavors, even on a molecular level, as herbs and spices and fruits and things like that.

level as herbs and spices and fruits and things like that. So it was this kind of fusion of, you know, being able to have kind of the x-ray vision of chemistry and put that together to connect into a delicious flavor. Why is it so, and it speaks to what you've said a couple of times, why is it so important to understand that flavor, and all of flavor, is molecules? I mean, I think it really boils down to understanding why you're doing what you're doing and how and when to go off-piste if things aren't going as predicted. I mean, maybe the simplest example is in culinary school, you get taught if you're adding lemon juice to a sauce or to a dish, you wait until the very end because if you cook the lemon juice, it will start tasting flat and less acidic. But if you look at the lemon juice on a molecular level, the acids

aren't actually changing at all as you heat it. What happens is that lemon juice has sour acids, but also a lot of lemony aroma molecules. And as you cook, those aroma molecules just get boiled off. And the flavor of lemon juice minus aroma is much flatter, much less sour tasting, even though you haven't changed the actual sourness at all. So that's not something you'd be able to understand unless you were looking at lemon juice as something that had molecules with particular properties. Again, it's not vibes. This is science. Exactly. Yes. properties. Again, it's not vibes. This is science. Exactly. Yes. Another example of this, and I mentioned this only because like right now is the time when I'm starting my tomato seedlings and I'm dreaming of the day in the summer when I pick a tomato from my garden and slice it up and put a little bit of flaky sea salt on it. And it's that incredible first bite that kind of changes

everything. You write about why a freshly picked tomato tastes the way it does. And there's science to this as well, right? There is, yeah. I mean, a freshly picked tomato, in the tomato itself, you've got sugars, which are sweet. You've got acids, which are sour. You've got glutamic acid, glutamate, which is umami. It's surprisingly a very high umami vegetable. And you've also got a little bit of bitterness from kind of the coating in the seeds.

So if you add salt on top of that, you get a real fusion of all five possible tastes. So aside from bugs, what are some of the ideas that chefs that you have consulted with at a place like Noma, what are some of the ideas that they would use that we could apply at home? Yeah. One thing we worked on a lot at Noma is about extending the kind of flavor and availability of very short season ingredients. So things like very delicious herbs and fresh plants and vegetables and things like that. And so one thing that we really like to do was make oils out of things like, you know, obvious ones might be dill and parsley, less obvious ones, different types of woods and flower buds and things like that. So oil is a fantastic sponge for flavor, especially aroma, and it's possible to kind of transfer all of the delicious flavors and aromas from something like a basil leaf or, you know, dill, etc., into the oil, and then basically store it almost indefinitely compared to, you know, a plant that'll die in your fridge in a week or so, and then have a really, really sexy

blanket of herb flavor whenever you want it. What's the relationship? I mean, it sounds obvious, but what is the relationship between taste and smell in creating flavor? So when I say that taste is a part of flavor, most people understand that easily. With smell, it's a bit more of a complicated picture, because when I say smell, most people think sniffing. So, you know, you get the picture of having a plate of food and you're sniffing it and the sniffing of those, you know, smells becomes part of flavor. And that's, you know, a small part of it. But you can actually smell food while it's inside of your mouth. So your nasal passage is essentially a tube, you know,

starting with your nostrils going into your lungs, passing via your throat. So air can go in the front way, sniffing, we call that orthonasal olfaction. But if you are chewing on food, the smell molecules are volatile, they float through the air. So they just will naturally float up the back of your throat and into your nasal cavity where they bind with your olfactory receptors, which sounds very clinical, but you actually are smelling every time you have food in your mouth. How vast is the world of smell in comparison to the smells that we can actually perceive? Almost literally infinite. Technically not. Almost literally infinite. We actually don't know the upper bound. So it's been estimated that up to 40 billion different molecules are potentially smellable. And then when you put those into mixtures, which all foods are

mixtures, the limit goes up to one trillion or more. What do you do with a piece of information like that? I mean, besides something that's fun to kind of whip out at a party to try to impress people, and it really just puts into perspective to me that it's important to get taste right when you're cooking, but smell and aroma is almost a limitless canvas to work on and is almost infinitely flexible, which is exciting to me. I want to ask you about some specifics. As a parent, one of the great joys in my life was getting my kids to eat bitter greens and love bitter greens. There are people who might be afraid of bitter flavors. How should we feel about bitter?

We should feel... How should we feel about bitter? Well, so children tend to have more taste receptors overall than adults. So if we feel frustrated feeding them vegetables and they don't like them because they're bitter, they do taste literally more bitter to children than they do to adults. They're not just being picky. No, exactly.

Yeah. I mean, they are being picky in the sense that that's an evolutionary strategy, but they're not doing it just to mess with you. But also, you know, across adults, there's a range. And some people produce, you know, twice or five times as many taste buds as the average person they're called super tasters and and foods actually taste much more intense to them as well sometimes you say that bitter needs a chaperone what do you mean well so bitter is a taste that uh that that we have to warn us about potential poisons and toxins. So yeah, it is a, you know,

unlike something like sweetness, which we're naturally attracted to, bitterness is a deterrent taste. But sometimes it is useful to be able to eat bitter things. A lot of sort of bitter plants act as medicinal compounds. So we've developed the system where if you're exposed to a bitter taste with, you know, that has other flavors like vegetal or broccoli rubbish or roasted and aromatic like coffee, the more times you experience that particular combination of flavors along with bitter,

the more your brain kind of relaxes when it perceives that signal. What might one of the chaperones be? Can you give an example of that? When it perceives that signal. What might one of the chaperones be? Can you give me an example of that? Yeah, I mean, sweetness and sourness are both really, really good at tempering bitter. Salt is surprisingly excellent at it. Not a lot of people would intuitively think of that, although there are a lot of, in the American South, dishes like cantaloupe with salt sprinkled on it to make it sweeter. And salt will actually interfere with the bitter receptor at a molecular level and make it less good at picking up on bitter compounds. So salt, excellent, all-purpose, non-bitter thing. In 2017, it felt like drugs were everywhere in the news. So I started a podcast called On Drugs. We covered a lot of ground over two seasons, called On Drugs.

We covered a lot of ground over two seasons, but there are still so many more stories to tell. I'm Jeff Turner, and I'm back with season three of On Drugs. And this time, it's going to get personal. I don't know who Sober Jeff is. I don't even know if I like that guy. On Drugs is available now wherever you get your podcasts. Let's talk about one of my other favorites, which is sour.

You say sour is like the little black dress of tastes. This is true. Tell us more. Really, sour is appropriate for almost any occasion. There's so many different dishes that can benefit from sourness, whether that's like salads or a soup or a little dish of grains. I mean, even sushi rice is tossed in vinegar before it's made into sushi. On a sort of scientific level, sour is also, I call it a little breakfast because it's versatile.

We can taste it for multiple reasons. On the one hand, we can sense if something might have acidic vitamin C, ascorbic acid, and not get scurvy. ability to sense it, they were more likely, when they were eating food that wasn't that fresh, to go for the lacto-fermented food as opposed to the spoiled food, food that had been fermented by other organisms. And if you were able to do that, able to develop a taste for that, you'd be much more likely not to poison yourself, and you and your descendants would be able to live on and pass those sour tasting genes onto your descendants. You have a neat little thing about, I mean, people often encounter sour through vinaigrettes, right? And so you make a vinaigrette and you add red wine vinegar, white wine vinegar, sherry

vinegar, what have you. You reframe it and you say, if you think of a vinaigrette, not just as a vinaigrette, but as a sour sauce for leaves what does that do um well then if for example you don't have vinegar or if you don't like the taste of vinegar um the reframing of a vinaigrette as something that contains vinegar to something that needs a sour component uh suddenly opens up a like huge range of possibilities because, you know, sourness shows up in vinegars, obviously, but also citrus fruits, other fruits like tamarind and pomegranate molasses, and also in other fermented things. So the pickle brine, for example, you know,

my mother would always add to potato salad for kind of like a tangy zip. But even things like cultured dairy, so like sour cream, buttermilk, creme fraiche. If you're making Greek yogurt, you tend to usually hang it and let some of the liquid drip off. That's yogurt way. That's very acidic, very clean and nice tasting and can go in a lot of dishes where you might otherwise use something like a lemon or vinegar. I love that idea. You mentioned fermenting. I mean, that's one of those things that I think people often will just leave to the professionals for fear that they're going to perhaps poison their family or make people ill or what have you. And yet we talk a lot about the importance of gut health and kimchi and sauerkraut and other fermented things.

of gut health and kimchi and sauerkraut and other fermented things. How can we do fermenting at home? And how can we do it safely at home? Yeah, I think there's definitely like a healthy amount of caution that's good to have, especially with some more advanced fermentations. I wouldn't recommend someone who's never fermented before to just start off with soy sauce or something like that. But very simple fermentations like vinegar or creme fraiche essentially make themselves. And the way that you make them, rather than having to go out and buy a special starter,

you can just start with a little bit of vinegar or a little bit of creme fraiche and then inoculate that into, you know, some wine in the case of vinegar or some cream in the case of creme fraiche. In the business, we call that back slopping. Very charming word. And just kind of leaving it on its own in a slightly warm spot. You'll get creme fraiche roughly overnight and vinegar in, you know, a couple of months. fresh roughly overnight and vinegar in a couple of months and very little effort involved and very obvious when it's gone wrong because if it doesn't go sour, don't eat it. It's that simple. That simple.

What about MSG? You have a little recipe in the book for zucchini that involves MSG. And MSG, for a long time, and there's a bunch of reasons why that you explore in the book as well, for a long time, people look down on MSG. How should we think about it? Well, so MSG is monosodium glutamate. It's a salt of glutamic acid. And once it's on your tongue, once the MSG dissolves in water, the glutamate in it is chemically and biologically indistinguishable from the glutamate in something like soy sauce or miso or your tomato. So I think MSG partly tends to get villainized because the name sounds scary and chemical when, you know, the molecule is actually the same molecule as you'd get from a fermented or aged food. I like to use MSG in certain situations

the same way that I'd use salt, frankly, because you get a very, very pure umami flavor from it. So, well, the recipe I have in the book has you slice zucchini really thinly and sprinkle it with a little bit of MSG. And yeah, the very clean umami flavor along with the kind of, you know, creamy vegetal-ness of the zucchini just makes for like an incredibly delicious and satisfying snack. Can I ask you about something that it seems like everybody's putting on food right now, which is Chili Crisp? This has been around for a long time, but it's kind of, and part of this is what happened over the last few weeks when David Chang, superstar chef, tried to argue that he had some sort of trademark on the name Chili Crunch.

But he changed his mind on this. He got a bunch of blowback online. But it feels like people are putting Chili Crisp in just about everything these days. What is going on in the Chili Crisp that I love on all this food? I love on all this food. Well, so for those who, the listeners that haven't had chili crisp before, it's chilies, onion, garlic,

some spices heated up in oil so that the flavors extract into the oil and all of the little solid bits get crispy. So the crisp is literally, you know, the garlic, the onions, the crunchy chili. So, I mean, people love it because it's spicy. We love spicy things. Spiciness releases endorphins that make us feel awesome. And, you know, it's an easy way for the thrill seekers among us to get that rush without much actual danger.

But I think what's, you know, delicious about Chili Crisp is all of the spiciness and all of the aromas get extracted into the oil. So, you know, like the oil I was talking about before, you essentially get a blanket of aroma and of spice, which is a different sensory experience than biting into, you know, a fresh chili or a dried chili, which usually comes on very fast, very sharp, and then dissipates. When you dissolve spicy stuff in chilies, the molecule is called capsaicin, in oil, it kind of lingers on your tongue and bathes it in this very gentle but very present heat. And so then when you combine that with the textural element of crunch,

everyone loves crunching through things, I think it's an enjoyable form of sensory overload, essentially. It's kind of a flavor bomb as well. Exactly. Yeah. I mean, knowing what you know, people might use things like that or hot sauces or condiments as kind of a cheat. But do you think of them like that? Or is your fridge just filled with condiments and hot sauces?

Oh, I love condiments. Yeah, I and hot sauces oh i love condiments um yeah i love hot sauces i love uh ponzu sauce which has you know soy sauce and and vinegar and citrus um yeah i i do you need like a separate refrigerator for all of the sauces that you have i really i really ought to it's it's taking over our our fridge which is a problem after we come home from uh grocery shopping definitely but no i'm i'm generally very pro-sauce. Does knowing all of this stuff about the science of flavor, because it's a science and you can run through the granular details of it, does that enhance your love of food? Oh, absolutely.

You know what I mean, though? Like somebody who knows so much, it could just be reduced down to ones and zeros. somebody who knows so much, it could just be reduced down to ones and zeros. Well, yeah, I mean, you know, I'm reminded of Mark Twain talking about, you know, knowing too much about river boating and the Mississippi River totally took the enjoyment of looking at rivers out of him, which I actually haven't found. I mean, for me, I love knowing how things work. Pretty much any, you know, hobby or interest I pick up, I pretty compulsively have to study until I understand, you know, why I'm doing what I'm doing and mechanistically what's happening. know, intense and pleasant sensory experience and understanding why that's happening. Or if it's an unpleasant sensory experience, understanding why that is and how I can fix it. So for me, it is a source of joy that goes along with the, you know, really primal

sensory component of flavor. Do you have a comfort flavor? I was gonna say like favorite, but it's not favorite. It's like the flavor that just gives you, I mentioned the tomato earlier. That's the kind of thing that makes me happy. What about for you? I really like, I like those peanut butter cups. So yeah, peanut with sweet and salty is just deeply, deeply comforting for me. I'm really glad to talk to you. I love this book.

My copy is filled with all these little notes and post-it things and marks on it. It changed the way I think about the food that I cook and I eat. Thank you very much for talking to us. Thank you so much for having me. Arielle Johnson's new book is called Flavorama, a guide to unlocking the art and science of flavor. I spoke with her in May. For more CBC Podcasts, go to cbc.ca slash podcasts.