Frontiers of Food Science: Do Sound and Color Affect Flavor? | Christopher Kimball’s Milk Street

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Episode 502
January 8, 2021

Frontiers of Food Science: Do Sound and Color Affect Flavor?

Frontiers of Food Science: Do Sound and Color Affect Flavor?

Experimental psychologist Charles Spence introduces us to gastrophysics, the science of how the brain melds color, smell and sound to create powerful multisensory taste experiences. Plus, Nicola Twilley investigates the rise of alternative sugars; Alex Aïnouz goes on a hunt for the ultimate knife; and we offer a recipe inspired by Tel Aviv’s Shlomo & Doron, where hummus gets a Mexican twist.

This episode is brought to you by Sleep Number.

Questions in this Episode:

“My doctor recently suggested that I go on a Mediterranean diet. Do you have any advice on how to slowly introduce that way of eating into my daily menu planning?”

“I love making bread, but I've been having a weird problem. On my second rise, the dough rises really unevenly, leaving one corner of the loaf either really puffy or super flat. What is going wrong?”

“I have a small kiwi berry arbor. We sell our best berries at local markets, but also experiment with making other products. Recently, we’ve been trying to make a kiwi berry paste similar to the quince paste, membrillo, but we can’t get the right texture. Any suggestions?”

“How do I freeze leftovers containing milk or cream so the soup or sauce does not curdle when it is defrosted?”

Milk Street Radio Charles Spence

Christopher Kimball: This is Milk l Street Radio from PRX. I'm your host Christopher Kimball. Today we're talking with experimental psychologist Charles Spence about gastro physics, including how sound can have a profound impact on flavor

Charles Spence: How often do you cry in response to seafood? Never, I think is the answer for most of us, why am I even wearing headphones at all when I eat my seafood. And then at some point, all of those sensory triggers are resolved themselves and you kind of get it.

CK: Also, toppings on hummus and searching the world for the best knife. But first, my interview with Niki Twilley, who volunteered to taste her way through alternative sugars. Niki, welcome to Milk Street.

Niki Twilley: Thank you for having me.

CK: Let's start with the we consume here in the States three pounds of sugar per week or some enormous amount. And so the industry is looking for ways to deliver the same level of sweetness, but with fewer calories.

NT: Yeah, that's the huge problem. The average American I think consumes something ridiculous, like 19 teaspoons of added sugar a day. And the World Health Organization says you should be doing six teaspoons max ideally three. So that is a huge gap. And food companies are trying to figure out how they can do something about it,

CK: Are sugar receptors. I think the quotas are tuned to the level of a ripe banana. In other words, you have to use a lot of sugar to know what sweet versus bitterness you can you can tell right off.

NT: Yeah, our receptors are tuned to help us find sweet, delicious things, you know, when we were roaming around the forest looking for fruit. And we weren't surrounded by ice cream and chocolate and candies. They are much, much less sensitive than our bitter receptors because bitter receptors are meant to detect things that might kill us.

CK: The other problem is that sugar isn't just sweet. There's color, there's mouthfeel. So, part of the problem is if you remove sugar, you've got to put something else back right to imitate the whole experience.

NT: Oh yeah, sugar is integral. I mean, this is why sugar shows up in foods that you don't even think of as sweet things like you know, mayonnaise or dressing for salads or things like that. It's because it's so useful. And it's so cheap. And so food manufacturers just use it in everything.

CK: So, let's take some specific examples of these alternate sugars. Nestle launched a couple years ago, Milky Bar, Wowsoms, a crispy filling, surrounded by shelf chocolate 30% less sugar, but they eventually pulled it from the market. Because people didn't like the texture.

NT: Yeah, so this was their attempt to debut what they call structured sugar. So, this was a really ingenious solution, where they took a sugar crystal, they mixed it with dried milk, and they sort of sprayed it out of a gun so it all dried into this porous sort of structure. So, imagine like a pumice stone rather than a dense rock. So, you're getting fewer calories, because there's all these holes but more surface area and enabled them to use 30% less sugar, but people didn't like it.

CK: So, one solution is to change the structure and aerate it. The other is to add pluses. So what are pluses and how are they fit into this whole model?

NT: Yeah, and people have developed a range of sort of fibers and sugar alcohols and things like that, that you can add back in to replace those missing the missing bulk and mouthfeel and crispness. But a lot of people complain that the fiber brings this sort of beanie taste, which is not what you're looking for often in a sweet food. So, we might not even know why we don't like something. But that's what's going on. Often, you're detecting these kind of off notes, these weird sensations without even necessarily being able to articulate it.

CK: There's another part to this you describe which is really interesting. You're getting a message from the brain saying, hey, a whole bunch of sugars about to enter the bloodstream here. But it turns out it's a sugar that is actually twice as potent so there's less of it. Is that a problem with the body trying to figure out how to balance everything?

NT: Yeah, that was my concern too. After I had sampled hundreds of these. I thought what am I doing, you know, I'm telling my body to gear up, produce all this insulin be ready for this massive wave of sweetness that's about to hit it and then there's you know, only 40% of the sugar isn't my body going to get fed up, if I keep telling you to freak out. And then there's no reason to freak out. According to scientists, that is not necessarily a problem, there is a built-in safety net, that will sort of tell your pancreas to calm down and not send your your blood sugar levels wild. But there is a lot we don't understand about what eating sweet things and having those sweet signals in our body is doing other than just making us happy. So one is that there are sweet taste receptors all over our body, they're in our lungs, they're in our digestive tract, they're in our skin. Men have them in their testes. And there's another, this was astonishing to me, our bodies are so clever. There are two different kinds of sweet taste receptors. They both taste sweet, but one is only happy if that sweetness is coming with calories. It can tell if you're trying to fool it, basically.

CK: So, what are some of the artificial sugars? I mean, you tasted a bunch. First of all, what was the tasting like? What did you taste?

NT: It was so interesting that you say artificial sugars, because I kept saying that too. And everyone kept saying, no, these are sugar, they're just slightly tweaked. And that's what makes them different from this whole history that we have of artificial sweeteners, which are completely different chemicals that just happened to taste sweet. So there's an Israeli startup that has a really cool product called Incredo, they mix tiny, tiny grains of silica, a 50th the size of a human hair really tiny inside the sugar crystal. So, if you picture sugar crystal as like a blueberry muffin, the silica is the blueberries. And what that does is okay, that's space that is not being taken up by sugar now. And weirdly, the addition of silica makes the sugar that is next to it, turn into a slightly different format. And that tastes sweeter for some reason on your tongue. I talked to a chef who was working with Incredo and she said actually, for some things, it's perfect. Chocolate, it's great. shortbread cookies, amazing actually makes them a little crispier. But for cakes, it's really hard and you do have to add back in something to make up that missing bulk.

CK: It's it's so interesting for 99% of human history, we basically had nothing sweet, right? Except if unless you were rich. This is a very new phenomenon in evolutionary terms. And it's like a wildfire it's it's totally out of control.

NT: Completely and it's I think it's sort of unfair to expect us to be able to control ourselves when it is in so much food all around us and our bodies have not evolved away to tell us that that's too much. So, I said to one of the scientists, you know, can we not just evolve to a bit of restraint now that we live in a different environment, you know, how your environment shapes you in evolutionary terms? And he said, Well, sure. Have you got 200,000 years? And of course, we don't.

CK: So, your thoughts for the future 20 - 30 years from now, where do you think we're going to be with sugar?

NT: I, I'm kind of a puritan at heart. You know, this business of being able to have sweet things without any consequences, it seems wrong. But at the same time, some scientists actually think we are going to be able to pull it off. And if we can pull it off, we could have all the pleasure of sugar without the disastrous consequences. I mean, the teeny, weeny, Hellenistic part of me that hasn't been squashed by my Puritan soul. Feels like that sounds amazing. In general, we have not proven to be terrific at fooling our bodies. But, you know, science moves fast. Who knows?

CK: Nikki, thank you so much. It's been a real pleasure. Thank you.

NT: Thank you.

CK: That was Nikki Twilley, the host of gastropod. Her article for The New Yorker is The Race to Redesign Sugar.
Now it's time for my co-host, Sara Moulton and I to answer some of your cooking questions. Sara is the author of Home Cooking 101 and of course star of Sara's Weeknight Meals on public television. So, before we take calls, Sara, I do have a question. I would bet there's something really embarrassing going on in your kitchen occasionally you use some convenience product. You eat marshmallows every night after cocktails, you do something you don't want anybody to know about. So tell me, what is that thing?

Sara Moulton: Peanut m & m’s I keep in the freezer. I have five every day with great relish and I don't even like milk chocolate. But I just love peanut m & m’s and I love them frozen, even though that's counterintuitive too, because if something's frozen, it doesn't have as much flavor but there you go.

CK: is this a bedtime snack or is this spaced out during the day

SM: no no no not a bedtime. No, it's after lunch I have iced coffee and five peanut m & m’s. I go to hell with myself. What can I tell you? And don't tell anybody else. Okay, Chris.

CK: I was not expecting that.

SM: It's like Julia Child and her Pepperidge Farm Goldfish that she pulled out for a hors d'oeuvre when she didn't feel like making one.

CK: Every time I went over there, she had Goldfish

SM: Had Goldfish. Yeah. Well, let's take a call. Welcome to Milk Street Who's calling?

Caller: Hi, it's Glen from Pickering, Ontario, Canada.

SM: Hi, Glen. How can we help you today?

Caller: Well, I was just speaking with my doctor recently. And he suggested that I go on the Mediterranean diet. The reason I'm calling today is I want to start implementing this into our daily meal routines. My wife and I, we work nine to five Monday to Friday. And to be honest with you, by the time we get home, we're not really in the mood to spend a lot of time cooking dinner. So, can you give me some simple ideas and advice to get us on the path to using this diet in our lives,

SM: Right. So, there's a couple things you can do whenever I make dinner, I have at least three elements. And I make sure that I focus on one of them. And the other two are just simple as can be. You could cook up a batch of farrow or brown rice on a weekend and then just park it in the fridge. And then you can just quickly reheat it or if you wanted to make them fancy, then you could add other things to them like some nuts with some chopped fresh herbs. roasted vegetables are very easy. You could even buy sometimes in the supermarket already cut up vegetables, you just put it in a 425-oven tossed with olive oil, little salt and pepper. And then you can focus on the protein which could be either fish or lean chicken or pork. I also want to encourage you to embrace a few frozen vegetables. Frozen peas are just fine. frozen corn is just fine.

CK: One thing I know a friend of mine does Jose Andres he will get a big pot of water boiling almost every night. And he'll just throw vegetables in it in order depending on how long they take to cook. So, he might have three or four vegetables in there. drain them, put them on a huge platter, some really nice fruity olive oil on top and salt. You could throw some fresh herbs on it if you like but that is sort of the centerpiece of his table all the time is just boiled vegetables, not steamed, you know not sauteed. I agree with Sara about grains. You know, rice cooker can do a lot of different grains. If you get an electric one. You think about grains as the base the foundation, for example, there's some cuisines, what they think about rice is sort of the thing that absorbs the sauces, along with vegetables, and protein. So, you think about that as sort of your base, which is great. And then I would think about vegetables as the center of the plate there. Plenty of cuisines most cuisines, where, you know, Europe had a lot of meat, and America has a lot of meat as the center of the plate. But most places don't because meats expensive. It's more of a flavoring. So, go get cookbooks and recipes where vegetables really are that the key component of most dishes and think about cooking that way. So those are my quick tips.

SM: Yes, good ideas.

Caller: Oh, that was great. Thanks for the tips, guys.

SM: All right, Glen. I hope that was helpful.

Caller: Thank you guys.

SM: Bye, bye. Bye.

CK: This is Milk Street Radio. If you have a question, give us a call anytime at 855-426-9843 that's 855-426-9843 or email us at questions at milk Street. Welcome to Milk Street who's calling?

Caller: This is Kaitlin in Burbank, California.

CK: How can we help you?

Caller: I've been having some troubles with bread lately. Here's my situation. Everything is fine on the first riise. But once I shape the dough and leave it to prove a second time, it can rise like super inconsistently. Like 90% of it is even a lovely but there's always like one corner that's either like crazy puffy or it's flat and sad. And this has happened to me twice lately, both on a brioche and a focaccia. I'm wondering what what it is that I'm doing wrong in either the shaping or in the second rise. That's like making it really inconsistent.

CK: I think it's about the shaping because as you said it wasn't in the middle, it was in a corner. You know, one trick is when you're shaping something that's rounder, you tuck the edges in underneath to get that nice, taut outer surface so it rises nicely, but my guess is you are overworking at one of the edges. It's too thin. I don't think it's proofing time or rising time because if the rest of the dough rises properly, it's clearly a shaping problem. Is that right? Sara would you agree?

SM: I agree. It's a thickness issue. Yeah, you know, brioche is somewhat freeform. Yeah. So, if it's freeform, it's much harder to keep it the same thickness. Did you say brioche was one of them?

Caller: Yeah, one corner was like a little Franken brioche. It was all puffy. And all of the other corners rose really nicely.

SM: Yeah. I wonder if you'd want to do it in a loaf pan instead

CK: Can I ask you a question? Going back to focaccia. How do you shape the dough when you shape it,

Caller: I just stretched it out by hand.

CK: So you have no floured surface, and you're just using the palms of your hand and stretching it out.

Caller: Yep. And then just use my fingers to poke the holes in it.

CK: And it you are stretching it out from the center essentially,

Caller: I never really thought about it that way.

CK: If you start stretching from the outside, like pushing the edges out that's the problem sometimes. Instead, if you do most of your shaping from the center out, you're not going to be playing with the edges as much and you won't overwork them.

Caller: Okay.

CK: And another question I have is when you shape it, is the dough snapping back on you at all or is it pretty much staying in place as you shape it?

Caller: A little bit, but I don't think it was like an abnormal amount it seems pretty okay.

CK: Yeah, I make a pizza dough, which is based on a focaccia recipe. After I shape it. I let it sit for 20 minutes, then I top it then elicit another 20 minutes. So, giving a lot of time after shaping really would help.

SM: That doesn't explain the brioche though.

CK: Well, no. The brioche if one of the corners puffs right up. I would say that's the special part and say it's a special brioche.

SM: Oh, that's the Julia rule never apologize. never explain.

CK: Is the inside of that portion that rose more properly cooked and a good texture?

Caller: It all tasted really good. Like it came out good. It just looked really funny. I was Sara.

CK: I’m with Sara never apologize

SM: Yeah, as long as it tasted good, who cares? And you know what, you’ll keep making it. It sounds like you will and you'll probably figure it out just with repetition.

Caller: All right. I will. I will embrace my flawed brioche.

CK: Don’t call it flawed. Find a French adjective for it, come on Sara help her out here what is she going to call it?

SM: Extraordinaire.

CK: Brioche extraordinaire Yeah,

SM: Yes there you go

CK: Brioche magnifique.

SM: Yes, there you go.

CK: That's perfect.

SM: Much Better.

Caller: Merci beaucoup.

CK: Take care.

SM: Okay

CK: You are listening to Milk Street Radio up next, Charles Spence on the science of taste. That's right up after the break.

This is Milk Street Radio. I'm your host, Christopher Kimball. My next guest, Charles Spence asks the deep philosophical question, what are flavors? Do they exist in the food itself, or in the interaction between the diner and what he or she is eating? At his lab at Oxford University, he investigates not just the nature of food, but how we perceive the world around us. Charles, welcome to Milk Street.

Charles Spence: Thank you. It's a pleasure.

CK: So, let's start at the beginning. What is gastro physics?

CS: Such a new word it’s a long word. It combines gastronomy on the one side. And then the other. The physics comes not from regular is expert from psychophysics, which is a branch of psychology. We try and systematically study what people perceive to try and understand the sensory triggers that really drive our enjoyment and perception in the world of food and drink.

CK: There's some famous examples of these experiments. I think you've teamed up with Heston Blumenthal, who was the proprietor and chef at Fat Duck. The one I didn't know about was a group of diners were presented with scoops of bacon and egg ice cream, playing sizzling bacon, for some of the diners and then clucking chickens for another. And the results were different in terms of taste perception.

CS: That is right. Back in 2007, we had about 150 people who paid their money to come and see some sort of food experimentation going on. And as the date approached, the chef and I hadn't done enough planning, we didn't know quite what to do to entertain these people. And it was that sort of moment of panic almost. Why not do something crazy. And so we thought, why not just play the sounds of sizzling bacon, or farmyard chickens, and see what happens? Never thinking it would work because why would it? Why would ambient soundscapes affect the taste of food, and yet the results from those people showed a very clear difference that we could bring out the bacon-y flavor by playing the sizzling bacon sounds. Bring out the egginess in the ice cream by playing the farmyard chicken sounds. And at the same time, we showed that you could enhance people's enjoyment of oysters by playing the sounds of the sea as compared to modern jazz music.

CK: I interviewed Heston Blumenthal a while back. He said that when people listen to these sounds, which I guess were available on an iPod at the time, sound of the sea or a summer day by the sea. He said that some people actually started crying. (Yes). So, this wasn't just a function of heightening the flavor of oysters or caviar. It was deeply resonant on some other level.

CS: Absolutely. I think how often do you cry in response to seafood? Never, I think, is the answer for most of us, and yet it does for a remarkable number of people trigger that response. And what is it that causes people to cry? I suspect it's maybe in the sound of the sea case, it might be that the sound of the sea is kind of a nostalgic sound, our childhoods are probably spent at the seaside. And maybe it triggers that nostalgia and emotion on the one hand. But I think on the other, I wonder whether it's not a case that when you're presented with all this stuff in one of these fancy molecular modernist restaurants, there's like too much going on. You can't quite mix head or tail of it, why those sounds and headphones? Why am I even wearing headphones at all and eat my seafood? And then at some point, all of those sensory triggers are resolved themselves and you kind of get it.

CK: That I've never heard that before. It's a fascinating theory. So, resolving complexity and tension into simplicity is part of the powerful emotion here?

CS: I think so. And if they cry, that normally means something bad, doesn't it, it means they're upset. But that sort of response, I think is clearly a legitimate and oftentimes pleasurable or memorable response to a dish in a restaurant, but just one that's, you know, hard to tease apart perhaps from, from other reasons for crying that you might have.

CK: So, what does science know, or suspect about the relationship between taste, aroma, emotion in memory.

CS: The pleasures of the table primarily reside in the mind and not in the mouth. And by that, I mean that, you know, we all think we all experience the taste of food and drink in our mouths. But that is just such a wonderful trick or illusion that our all of our brains ___because what we taste, both what we think we taste and how much we enjoy that experience, really comes from the combination of the integration of, of what's going on, on our taste buds on the tongue, but also a smile and a sight and of sound and of texture. And of course, beyond that kind of mood and emotion play into an all of those cues first come together and are integrated in our brains. That's where flavor experience and in a way really happens. We can see and we can hear and we can touch and we can taste. And those are all separate sensors on the outside with our eyes and ears and nose and so on. But In fact, wherever you look in the brain, it seems that the senses are integrated. And in a way, for me as a multi-sensory scientist, there's nothing that is more multi-sensory that engages more senses than flavor.

CK: We've talked about enhancing the experience of eating through auditory signals. But the opposite is also true, I think, an airplane with a very loud background noise your sensory perception is lower.

CS: That's right. Very loud background music has been shown to interfere with our ability to taste in ways that are really interesting, because you might just think well, loud noise that's just sort of masks everything. You can't taste anything with loud noise. And yet, it turns out that the impact of at least airplane noise is very specific, curiously specific, in that airplane noise seems to impair people's ability to taste sweetness, perhaps also saltiness, but it actually enhances their experience of umami, that mysterious fifth taste that you find in tomatoes and mushrooms and parmesan cheese and so on. And that explains why it is that so many of us will drink tomato juice or Bloody Mary only on an airplane and never think about ordering that while we're on the ground.

CK: I guess also, you've done studies to indicate that visual clues make a difference.

CS: So, vision plays a really important role in helping us to predict what something will taste like. So, if I see something that's brightly colored, I probably expect it to be intensely tasty. If I see something pinkish, I probably expect it to be sweet. If I see it yellow and green is probably going to be sour. So, there are lots of associations and expectations we all have with color in food. And by setting those associations, you can bias people's expectations before they taste. In the case that I start my astrophysics book with from chef Heston Blumenthal, the chef served a pink ice cream. And that pink color is really the color of frozen crab bisque or smoked salmon ice cream. The pink is natural, it's perfect. It's just that his diners who haven't been told what this dish is called yet, are imagining raspberry. And if you imagine raspberry and sweet, and you taste savory, that's a great example where modernist or molecular cuisine can start to kind of pull apart the senses in a dish.

CK: Does this go beyond the expensive restaurant into the world of the everyday man or woman. I mean, other words, why do I care about whether Heston Blumenthal can do sound of the sea or not right?

CS: That question is fair, who cares? what goes on at the fancy restaurants are too expensive or too difficult to get a table at this kind of irrelevance of curious, entertaining, but nothing more than that. But for me, I think, no. In fact, so often, I've what I've seen is that we come across some scientific insight in the lab that's then passed on to the food companies and to the chefs. You know, my favorite example is about Patagonian toothfish. A fish that sounds so unpleasant, that when you see it a picture of this fish, it looks unpleasant, but it's sustainable, it's healthy, it's nutritious, we should all be eating more of it, no one ate it. But simply by changing the name of that fish on restaurant menus to Chilean sea bass. Suddenly, sales increased by 12 100%. As a result, so potentially This is all very powerful stuff. But when you find some of these illusions, you can illustrate to people how their mind is playing tricks on them in a way. But then beyond that, think about how one can incorporate that knowledge into the better design of of everyday things, be it the food on your plate, or the environment in which we work and live.

CK: Okay, so let's do a few experiments now to put theory into practice. And so what are we going to start with?

CS: I think we should start with a little bit of toffee. What I'd like you to do is get a piece of toffee ready. And when you hear the first piece of music start, then bite into the toffee and think about how bitter or sweet it tastes.

CK: Slowly, okay.

CS: Maybe think about 10-point scale where one is very bitter and 10 is is very, very sweet.

CK: I'd say six.

CS: Okay, so six out of 10 for sweetness.

CK: Well, so give it seven. Okay, we'll give it seven

CS: And now you want to get another piece of toffee ready and queue up the next soundscape.

CK: Much less bitter and more mellow. I'd say instead of a seven it’ll be more of a nine

CS: Probably on average, people would associate the first tinkling track more with sweetness. Whereas if you had to associate a taste for the second sound it’s lower in pitch. People would more often associate that with bitter

CK: Well, either I'm perfectly designed for my job, or I should get fired. I thought the deeper sounds were smoother and more comforting. And the bitterness which I associate with sharp was more connected to the sharper tingling sounds. Yeah, but that's just me

CS: So, you see, you know, in our experiments, and we'll do test 10 or 100 or 1000 or 3000 people, because there's no right answer to this.

CK: People always say that when in fact there is a right answer. You know that
CS: No there isn’t. There is a consensual answer. (Okay) I know what the majority of people will say, but there's no correct answer.

CK: Okay. The second one is?

CS: So next what I'd like you to try is to bite into two potato chips come and we're going to change the crunching sounds that you will hear as you bite into each one. And this time thinking not about sweetness and bitterness but think about how crunchy crisp and fresh that potato chip is. And then if your next potato chip ready, when you hear the sound to take a bite out of it, again, think about how crisp or fresh or stale or soggy it is.

CK: That actually worked. The first one really was crispier and the second one was definitely soggier. Yeah.

CS And these two cases that sound that you hear is kind of related to thing you're eating in a potato chip example. So, your brains got more reason to connect.

CK: Yeah, no, no, that was had a very real impact on my experience. Okay, so what's the third here? We have a I have a bottle of Guinness.

CS: This time when you hear the music stops, then take a sip.

CK: Okay

CS: of your Guinness and think about the taste

CK: Anything in particular and the taste I'm looking for?

CS: Yeah, I think about the bitter and sweet.

CK: Okay.

CS: Okay, ready for a second microphone?

CK: Yep. Sounds like Phantom of the Opera. I'd say the first one was sweeter. The second one was more bitter.

CS: It’s going to be impossible to to use music to turn water into wine so far but what you can do is take a complex taste and draw people's attention to something and what they're tasting.

CK: That's pretty amazing.

CS: We've got sweet music. We've got sour music, we've got spicy. We've got bitter, salty we're struggling with. But I think we've almost got it there. By drawing attention to these almost Sonic equivalences of tastes and flavors. We can bias your perception, your experience.

CK: Can I make a career suggestion for you? I would drop everything and figure out the music that turns water into wine.
I think you'd be a very wealthy professor very quickly.

CS: I'll be too busy to be on this radio show. That's for sure.

CK: You're never going to talk to me again. Charles, it's been just a lot of fun. And there's some deep themes here which I find fascinating. Thanks for being on Milk Street.

CS: It's a pleasure. Thank you.

CK: That was Charles Spence. His book is Gastro Physics, the New Science of Eating. We're told that reality is subjective that each of us has his or her own set of facts, and that nothing is absolutely true. This flies in the face of the Enlightenment, modern science and even Buddhist philosophy, which maintains that there is an objective reality beyond individual perception. Humans can only see part of the light spectrum for example, or hear a range of sounds, or as author Jim Taylor pointed out, just because we cannot hear a dog whistle that doesn't mean that the sound does not exist. Just go ask the dog.
It's time to chat with Rayna Jhaveri about this week's recipe, hummus with Chipotle black beans and tomato salsa. Rayna how are you?

Rayna Jhaveri: I'm well Chris, thank you.

CK: You know about a year ago I was in Israel and I finished the trip in Tel Aviv. And I thought well, okay, I'll go get classic hummus right. So, I went to the oldest and most venerable hummus joint in town, Shlomo and Doron. And there is a young guy there, and he wasn't about to serve me hummus hummus. He had Mexican hummus and Balkan hummus and shakshuka hummus and everything else, you know, falafel hummus. I was kind of shocked because I figured this is supposed to be the bastion of tradition. But Tel Aviv is a very modern town, and people are always you know, having fun with their food. I really fell in love with it, especially the Mexican hummus. I just think it worked well. So, put aside our purest authenticity here. And let's play with hummus.

RJ: Totally Chris. I mean, I'm a purist myself and fusion food has a difficult place in my in my world. However, this one broke me. This is a Mexican twist on hummus that added so much complexity and texture to the dish. We have smooth black beans, crisp jalapenos, fresh pico de gallo, and even some broken tortilla chips. It's a whole new way of thinking about hummus.

CK: Well, hummus is the foundation, right? It's definitely second place with all the other flavors, right?

RJ: There is a lot of flavor, but we're going to start this dish using canned chickpeas, and we're going to simmer them in their own liquid along with some baking soda to break down the skins a little.

CK: We cooked them what the typical food processor method.

RJ: Exactly, I mean the liquid of the chickpeas it's called aquafaba which is an amazing way of bringing all the ingredients together. So when the chickpeas are fairly broken down, we drain them reserve some of that cooking liquid. Then we add them to a food processor process about three minutes. Add salt, lime juice and tahini as well as the additional cooking liquidity end, so that's the base.

CK: Okay, so the black beans, you could either just put black beans on top, which I think is what they did at Shlomo and Doron. But I think here we decided actually to puree them, so you'd have to, you know, is similar to the texture of the homeless, right?

RJ: Exactly. So, we're making a second bean puree. Again, we're going to use a food processor to combine the black beans and there is a liquid along with some lime juice and cumin, as well as some Chipotle chilies in adobo sauce. So, this gives it like a really nice, smoky flavor. And we topped that off with some cilantro and pulse about two or three times.

CK: We were really happy with this. I think there are a lot of people in Tel Aviv, probably who aren't. They pointed out that some of the old timers there were kind of like, wait a minute, but this is one of those fusion things that as you said, kind of makes sense. You know, it really does. So we got the hummus, the chickpeas, we got the black bean puree, and now we need those fanciful toppings, right.

RJ: So definitely we want to change up the texture and add some more flavor. We're going to combine tomatoes, onion, jalapeno, lime juice and salt. Once that's mixed, we're going to start layering so we started with the hummus. top that with a black bean puree spoon on this tomato salsa and finish with some crunchy tortilla chips and fresh cilantro.

CK: Well, I don't think we're getting high marks for authenticity here. But it sure did taste good. So a great recipe from the heart of Tel Aviv hummus with Chipotle, black beans and tomato salsa. Thank you, Rayna.

RJ: Thanks, Chris. You can get this recipe for hummus with Chipotle black beans and tomato salsa at Milk Street

CK: This is Milk Street Radio. Next up French food scientist Alex Ainouz on finding the perfect knife. We'll be right back.
I'm Christopher Kimball and you're listening to Milk Street Radio. Right now. Sara Moulton and I will be answering a few more of your cooking questions.

SM: Welcome to Milk Street Who's calling?

Caller: It's Mike Russell, from Woodstock, Vermont.

CK: Yes, very good. So how can we help you?

Caller: About five years ago, I started growing Kiwi berries to grow them commercially. And when we go to bring them to market, we always have some that aren't suitable for sale. And so, we started to experiment with making jellies. And our first attempt ended up coming out really thick and dense, very similar to a membrillo.

CK: Do you want to explain what an membrillo is?

Caller: Oh, sure. It's a very firm paste made out of quince, that the Spanish often put on a hard cheese. And so, we are trying to make something similar. It really like it to be something that you could slice as opposed to something that you're spreading.

CK: And I assume you've tried pectin?

Caller: We did pectin the very first time, and it was tacky, and kind of almost clumpy. And we've experimented with using a food mill and jelly bags to get down to pretty much pure liquid.

CK: Are you using the low sugar pectin or the regular pectin?

Caller: Regular pectin.

CK: And I assume this is fairly low sugar.

Caller: Well, the fruit itself is very high sugar.

CK: I would say it's all about using pectin and using the right amount, that's all I can tell you, because otherwise, it's not going to be sliceable. One more time. So, when you use pectin, the problem was what?

Caller: It was almost clumpy as opposed to a firm block.

CK: That makes me think that maybe it needs more liquid with it. Maybe for a sliceable log or rectangle. You need to have a higher proportion of liquid of water in this and less fruit. Yeah, I would definitely go with pectin, but I would increase the amount of water in this recipe to get not as clumpy a final product.

Caller: That's interesting because the quince paste recipes that I was able to find they all use water obviously to boil down the fruit, but the quench is much firmer than the kiwi Berry. Yeah, that's a good idea. I'll give that a try next time.

CK: Yeah, that's the only thing I can think of Sara, do you have words of wisdom here?

SM: Oh, no, I am a little bit out of my league because I'm not a big jelly maker. I do know that kiwi is low in pect and so that obviously could be a factor here. But other than that, I defer to you, Chris.

CK: I think it's more water and just adjust the pectin.

SM: You're trying something new Mike, and I applaud you. That's great.

Caller: Yeah. Well, I'll tell you, even though it's not quite the consistency we want people can't stop eating it.

SM: Oh, well, that's good. Maybe you developed something new. Why does it have to be like membrillo, why can’t it be it’s own thing.

CK: Right. Exactly. I mean, my answer to everything is if they like it, you're done. Yeah. Don't worry about it.Anyway, Mike, it's been a pleasure. give that a shot. Yes.

SM: And let us know how it goes.

Caller: Yeah, I will. Thank you very much for your suggestions.

CK: Thanks, Mike.

SM: Mike, take care. Yep, take care.

CK: This is Milk Street Radio. If you need some help, please give us a call. Our number is 855-426-9843 more time 855-426-9843 or email us at questions at Milk Street Welcome to Milk Street Who's calling?

Caller: Hi, my name is Suzanne. I'm calling from Northport, Alabama.

CK: Okay, how can we help you?

Caller: When I thaw out leftovers that have a cream or a milk-based gravy or creamed soups, the creme liquid always looks curdled. heating the food doesn't cause that liquid to smooth out. It doesn't affect the taste at all. It just looks on appetizing. And I was wondering if you have any suggestions on how to prevent it from happening?

CK: How do you defrost it?

Caller: Generally, I just let it sit out.

CK: Well, that's not a bad way to do it. My guess is is the ice crystals, you know that form and then the fat droplets in the milk or cream or whatever get punctured, then you get separation. The only suggestion I make is maybe put it in the refrigerator overnight. So, a really slow defrost might help a little bit. But I don't think I have a solution to that problem. I don't think freezing in smaller quantities is going to help you very much. But I think the refrigerator at a slower rate might be the only thing that could help. It's that fat, you know it’s those droplets are separating out and curdling, Sara, any suggestions?

SM: Well, I have a crazy idea, which is a no seriously, they just came to me when you go to reheat it. Maybe what you could do is add a slurry, which is a starch mixture of flour and water cornstarch and water or arrowroot and water. When it separates out take a little bit of flour with equal amount of water whisk it together and then whisk it into the curdled mixture and it might bring it back enough to look appetizing. Meaning it will rethicken it.

CK: Are these like cream soups or is this creamy stew. What is it you're freezing?

Caller: Generally, it's both the soup and I like making veal paprikash, so it's still got the pieces of meat in it and the onions and stuff. I generally don't make completely smooth soups. So, there's always something chunky in it.

CK: Now Sara has decided to be crazy. I'm going to be crazier. Okay. Sara, are you ready? (Yeah) I would separate the liquid creamy part out from the solids before you freeze it and now here's the really crazy part, I'm going to steal Sara's idea by creating a slurry of the cornstarch and then whisking it into that liquid. And so, before you freeze it, you've stabilized the fat in the liquid, and then to frost them separately in the refrigerator. But if you stabilize ahead of time, that might kind of crazy but that might actually work. First of all, I tried the refrigerator overnight first. But if that doesn't work, I would try that.

SM: If you're using say heavy cream or crème fraiche, both of which have a much higher butterfat content, as opposed to regular whole milk or any other kind of milk or even sour cream or yogurt. Those tend to break a lot faster. First of all, we know if you boiled them without a starch in there. But also, I think when you freeze them, the lower fat dairy products tend to curdle more. So, if for some reason you wanted to use cream instead of milk, you might have better success. defrosting them. However, you may not want your soups to be that rich. Just a thought.

Caller: Typically, I use like whole milk or maybe heavy cream.

SM: Cream would be more stable than whole milk for sure. (Okay)

CK: I would definitely separate out the two though. (Yeah0 Then you can either do what Sara suggests or what I suggest. At least you could deal with the sauce separately. Yeah.

Caller: Okay.

SM: It would be great if you let us know how this goes. We always like to know if our crazy ideas work.

Caller: I sure will.

CK: Thanks for calling.

SM: Yes. Thank you. Okay,

Caller Bye bye.

CK: This is Milk Street Radio. Now it's time for some culinary wisdom from one of our listeners.

Caller: Hi, my name is Jack Wilson from Pound Ridge, New York and I have a tip for better and more exciting walk cookery. I love to stir fry, but my round bottom wok doesn't work well with my stove. Instead of adapting my recipes to a flat pan on the stove top I've used a variety of alternative outdoor heating sources. I’ve used the burner from a turkey fryer, charcoal in a grill. And most interestingly, a live wood fire either a campfire or fire in a fire pit by just plunking the wok down directly in the fire. The high heat and smoke from the live fire heat sources improves the flavor of the stir fry and it's fun to incorporate a wok in your outdoor cooking or campfire meals. The metal handled carbon steel wok works best for these techniques, but you can make it work with a variety of different woks. I highly recommend it.

CK: If you'd like to share your own cooking tip on Milk Street Radio, please go to 177 Mill Street com slash radio tips.
Next up its regular contributor Alex Ainouz. Alex, how are you?

Alex Ainouz: Hey Chris, how are you?

CK: What's going on in your Paris studio?

AA: You know what's going on, I've got a problem, Chris As always, I've got a problem. I'm facing like a life dilemma.

CK: Okay, I've had a few of those. I can help you with that.

AA: That's what I thought you'll my therapist is when it comes to cooking in general. So, my problem is about knives. All my life I've been looking I've been on the hunt for the best the ultimate chef knife when I started cooking like seriously, my dad got me a really cool knife a Sabatini knife, a French knife. That's a chef's knife. That's an all around. I don't know if you're familiar with French knives.

CK: Oh, yes, I have some _____.

AA: Yeah, yeah, that's what I thought as well. So that knife was super I developed my love for cooking with it. But then

CK: you fell in love with another.

AA: That's the problem. You know me Chris already

CK: This is a love story

AA: The problem is I went to Japan. Oh, exactly. There's no going back from this. I went to Japan and I discovered just like, knives. Yeah, there was a knife for every little purpose in the kitchen. So, what did I do? I bought as many knives as I could. So, I bought a chicken wing knife. That's how specific you can get. I'm sure you must have like Japanese knives yourself as well.

CK: Well, the thing is, the blade is so much thinner. And so, the European chef's knives feels like a chainsaw when you start using a Japanese knife because you're pushing less metal through the food. And so, it goes through so much easier. And I don't I don't understand the European chef's knife. It's like the heavier the better, right I mean, it's it's this race to weight. And the Japanese have the opposite, which is they want the lighter thinner knife, which I think is brilliant.

AA: It's like It's like discovering technology when you come from the Stone Age. It's like a discover something that is refined, thin like a professional tool. And it's dedicated for the job. I've seen these soba knives the knife to get soba noodles. I just want one. I want all the knife. That was one of the problems I must say because basically, it's like a bottomless spending bad habit to love Japanese knives.

CK: Every time you pick up a Japanese knife. You love that one more.

AA: Exactly, exactly. But then something else happened afterwards. I started getting really into a specific Chinese dish. So mapo tofu. And I thought, well, I can't make it a Chinese dish with a Japanese knife so I thought I'm going to use a Chinese cleaver.

CK: There you go.

AA: Exactly, exactly. Okay, anyways, I got one, it's not expensive this one. So it's called a____. It's thin as thin as a _____. The steel is quite amazing, I must say because it It remains to be sharp for a very long time. And the fact that the blade is so tall and so wide. I started scooping things out of the table using it as a shovel. But also, you can get through a whole head of cabbage super easily. You can also like do precise d- boning work.

CK: You can also you can slice a clove of garlic with it too>

AA: Exactly you can smash it as well. And I basically I'm just cooking with it all the time for all foods. So, my problem in the end is that basically I've got like drawers and drawers full of knives. I got knives everywhere in the studio, and then I just fell in love with an all arounder instead of all the knives that I had in the past what I was looking for control.

CK: Well, you know, Alex, you're just coming of age, man. I mean, like when you're 20 you fall in love with everybody you meet but when you're a little older, you really realize, Oh, yeah, this is this is true love right.

AA: Exactly. I can't believe you're bringing that up because that was exactly my point. My first love was local, I just went with it fell in love with it. Amazing. Then I was looking for more more control more technique more, more everything and then it just feels normal to go Japanese knives at that moment and then just going back. I feel like I'm slightly wiser. So, I want to get all that clutter out of my life. And I feel like the Chinese cleaver encapsulates all that. Like I've been working with a Chinese chef, I was learning how to make dumplings. And she told me that as I was wrapping up these dumplings, I was also making weird moves with my mouth. I was wasting energy and she told me use that energy and put it at the tip of your fingers this way you will be more efficient. Wow. That that's that's an advice you cannot come up with like this. This is something mystical, the Chinese cleaver it feels like it's the sum up of a whole civilization, their approach how they deal with tools, they are the tool you are the tool yourself. You adapt to whatever is coming. You fuse with the food almost.

CK: Alex Ainouz the Chinese cleaver is not just the knife. It's the philosophy of of the ages. Thank you so much.

AA: Thank you so much.

CK: That was YouTube host Alex Ainouz. He's also the author of Just a French Guy Cooking. That's it for this week's show if you tuned into later want to binge listen every single episode you can download Milk Street Radio and Apple podcast Spotify wherever you find your podcast. To learn more about Milk Street just go to 177 Milk Street com there you can find on recipes. Take a free online cooking class or order our latest cookbook Cookish. You can also find us on Facebook at Christopher Kimball's Milk Street on Instagram and Twitter at 177 Milk Street. We'll be back next week with more food stories and thanks as always for listening.

Christopher Kimball's Milk Street Radio is produced by Milk Street in association with GBH Executive Producer Melissa Baldino senior audio editor Melissa Allison, executive producer Tanya Ott, Associate Producer Jackie Novak. production assistant Sarah Clapp, production help Debby Paddock additional editing by Sidney Lewis audio mixing by Jay Allison at Atlantic public Media in Woods Hole, Massachusetts. Theme Music by to Toubab Krewe. Additional music by George Brandl Egloff Christopher Kimball's Milk Street radio is distributed by the Public Radio exchange.