The Science of Food: Steaks, Bugs and Expiration Dates | Christopher Kimball’s Milk Street

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Episode 418
June 4, 2021
Originally aired on June 12, 2020

The Science of Food: Steaks, Bugs and Expiration Dates

The Science of Food: Steaks, Bugs and Expiration Dates

We chat with flavor chemist Dr. Arielle Johnson about how to eat a tree, how insects use flavor molecules to communicate and the science of taste and smell. Plus, Meathead Goldwyn teaches us how to grill perfect steaks; J. Kenji López-Alt investigates food expiration dates; and we make a no-fuss, all-flavor Spanish Almond Cake. (Originally aired June 12, 2020)

This episode is brought to you by Sleep Number.

Questions in this Episode:

“I can get local grass-fed oxtail meat at my local supermarket for a very good price, and I love that there is collagen and marrow that will seep out of the bones and into the stew. Can you cook it without browning it first by either nestling it on top of sautéed onions and adding water, or by placing it in a Dutch oven without liquid and baking it in the oven, or by cooking it in a crockpot?”

“Is a quiche considered a pie? My husband and I have debated this and we want you to settle it.”

“I make bread a few times a week. Different ingredients call to be added at different times. Why is that?”

“When I make ice cream, it usually has a good flavor and texture, but always seems to leave a coating on the spoon. Can you explain what is happening and how to avoid it?”

“I recently called asking what to do with banana peels. I’m calling back with my results.”

Milk Street Radio Arielle Johnson

Christopher Kimball: This is Milk Street radio from PRX. I'm your host Christopher Kimball. Have you ever wondered what rain forest ants taste like? Today we have flavored chemists, Dr. Arielle Johnson to answer just that. We also discuss how wildfire smoke can flavor wine and the science of taste and smell.

Arielle Johnson: Taste molecules like sweet, sour, salty, bitter, and umami are mostly water soluble. And smell molecules, which is basically everything else are more soluble in alcohol and oil. So, if you're trying to express like coffee beans, it'll be more bitter and acidic if you make an extraction of water and then incorporate that. If you want to just have the aromas of coffee. Making a coffee butter or a coffee cream is a way to get that while avoiding bitterness.

CK: Also coming up we'll make a no fuss Spanish almond cake and later j Kenji Lopez Alt investigates food expiration dates. The first we hear from barbecue expert Meathead Goldwyn about how to properly grill a steak. Meathead welcome back to Milk Street.

Meathead Goldwyn: Oh, it's always good to talk to you, Christopher.

CK: So how to cook a steak on a grill. You and I've discussed this before. And you basically disagree with everything. Most people think about how to cook a steak.

MG: Well, I learned to grill from my dad, my dad learned to grill from his dad and his dad learned to grill from his dad. And that's the way most people learn to grill. And when you sit down and you think about it, and you apply some current science principles to it, you figure out that a lot of that stuff is just wrong.

CK: So, let's start with a cut. Thin steaks, thick steaks, which primal cut are we dealing with here?

MG: Well, you went right to the heart of the question right now. People always ask me how to cook a steak hot and fast or low and slow. And it all depends on how thick it is. Now this is you know, whenever you cook anything indoors outdoors, you're doing a physics experiment, and you're doing a chemistry experiment. This is physics, the steak is 70% water, it takes time for heat to move from the outside of the steak to the inside of the steak. Whether it's in a grill or an oven or a frying pan, the heat or it's actually better to think of it as energy, the energy is on the outside of the steak, and it heats up the outside of the steak, but it doesn't penetrate the steak. It's the heat that is stored in the outside of the steak that heats the inside of the steak and moves from the outside to the center. So, the warm air in your oven or in the grill is only cooking outside of the steak the outside of steaks like a capacitor or a battery, it just stores up the energy. And that moves to the center. So, it takes longer for a thick steak to cook than a thin steak, obviously. But if it takes longer than you need to dial down the temperature on a thick steak, otherwise you burn the outside before you reach the ideal temperature on the inside. A medium rare steak, which we know for a fact is most tender at 130 to 135 degrees. That's medium rare. You can tell with a digital thermometer right spot on, you don't have to cut into it. You don't have to poke it with your finger. You can stick it with a digital thermometer and know precisely

CK: But no. Okay, you know, I like to argue with people. (Me too) Yeah, I know, I've noticed that. That's why you're on the show. I've used the digital thermometer on steaks for years. But the thing I'm not sure about is you know, I know I pick it up with tongs, I insert the thermometer horizontally. But I got to tell you, if it's half an inch, one way or a quarter inch another way, I might do five readings and get six results. Yeah, it's it's kind of hard. So how do you effectively determine the internal temperature of a steak?

MG: Well, you want to look for the geographic center. I am but it may take more than one stick and you may have to do a little averaging in your head. It's not going to bleed to death. This is not a balloon, you stick it with a thermometer, it doesn't go and deflate. So don't worry about sticking it.

CK: So okay, so a flank steak would be cooked maybe differently than a two-inch sirloin or something. So, let's assume you have a thick cut steak. Now what? Okay,

MG: Okay, keep the temp down. I like to tell people when you're learning to grill, learn to manage to temperatures, a hot zone where you have radiant heat. Directly above that radiant heat is where you're going to sear, and the other zone is not hot. There's no heat directly below the meat. And that's going to cook the food by convection airflow, and you want to get back to around 225 and if you can nail to 225 whether it's windy, hot, cold, rainy, you're in control because cooking is all about temperature control, and it's harder outdoors than it is indoors. So, you're going to start your thick steak on the Indirect zone where it's cooking by gentle convection airflow at about 225. And it's going to slowly warm from edge to edge at about the same rate. And what you're essentially doing now is you're cooking the inside of the meat. And you're going to bring it up to just a little below what your target temp is, if you want a perfect medium rare steak 130 to 135, bring it up to about 125. And once it hits that, then you lift the lid, and you move it over to the direct heat zone. Now you're cooking. Now, by radiation, you're cooking with infrared radiation when you're directly above the energy source. And then you're going to flip it and you're going to flip it, you're going to be the human rotisserie, because you don't want to build up energy, you will just want to cook the exterior of the steak. You already cooked the interior on the indirect side. Now you're cooking the exterior, you're going for dark brown, mahogany, edge to edge bumper to bumper.

CK: Okay, so before you get the grill going, am I going to salt this meat and let it sit

MG: in advance of cooking, you definitely want to salt your meat. Salt is the magic rock salt is just sodium and chloride to little ions. And when they get on the surface of meat, they melt, and they go to the center. Nothing else can penetrate garlic sugar, they're the molecules are too large, they can't go more than a fraction of an inch just into the little tiny cracks and crevices on the surface. But salt can actually go deep towards the center. And what salt does is it alters the structure of the protein. And it helps it hold on to moisture. So, it amplifies flavor and holds on to moisture. Salt is magic. It's the most important thing on your spice rack.

CK: So, what about cuts? We didn't really talk about that. In terms of what primal cut are you getting a? You know, like a New York strip steak, a shell steak. What are you getting?

MG: Well you know, most real steak lovers will tell you the ribeye is their favorite steak. And there's good reason I mean it's the perfect blend of fat and protein. And you get a really great juicy experience. The ribeye has actually two muscles. There's this round muscle that occupies most of the ribeye, and that's the longissimus dorsi and it runs from the shoulder all the way to the hip. But there's this little curved muscle that wraps around the outside of it, and there's this thick layer of fat in between them. And that little curved muscle is the Spinalis dorsi, or the rib cap. That is the best muscle on the animal. The other steak I absolutely adore is the flank steak, which comes from underneath the animal. And it's a much tougher steak, but it's got so much flavor. And that baby you want to cook hot and fast. Get it right over the heat and sear it. Get it really dark, dark brown, maybe little little char on the surface, and medium rare in the center. And that's a great steak

CK: Meathead. Thanks so much everything I wanted to know about steaks but was afraid to ask thanks.

MG: Always fun talking to you, Christopher. Let's get together and cook some steak sometime.

CK: It sounds like a better idea. Take care. That was Meathead Goldwyn, founder of Amazing Ribs .com and the author of Meathead The Science of Great Barbecue and Grilling. Right now, Sara Moulton I are ready to solve your culinary mysteries. Sara is of course the star of Sara's Weeknight Meals on public television and also the author of Home Cooking 101.

Sara Moulton: Before we take our first call, I have a question for you, Chris, have you found yourself baking things you've never baked before.

CK: I'm a baker. I mean, that's my first love in cooking. And oddly enough, I've been doing mostly savory food now. But the one thing I have made over and over again is that corn cake I got from Mexico. It's absolutely to die for and it's very simple to make you make in a nine-inch cake pan. And you know, alas maybe a day in this household. So I every week I go buy three ears of corn because it uses fresh corn. And it's just spectacular. And the only sweetness in it is a mean like a 15-ounce can of sweetened condensed milk, which is typical in baking in a lot of cultures it’s delicious is not too sweet. It's just excellent. That's really my go to and since you know bananas with the kids, we just have oodles of bananas that are black. So, it's banana bread every week and corn cake. That's sort of where we are

SM: That's sort of sounds good to me.

CK: Not a bad place to be now anyway. Okay, on to calls. Welcome to Milk Street who's calling?

Caller: Hi, this is Carol, and I'm calling from Mount Shasta, California.

CK: How can we help you?

Well, I can get local grass fed oxtail at my grocery store for a very good price. And I love that there is collagen and marrow that will seep out of the bones and into the stew. Can you cook it without browning it first by either nestling it on top of sauteed onions and adding water, or by placing it in a Dutch oven without liquid and baking it in the oven, or by cooking in a crock pot?

CK: Sure. Years ago, and mostly we came up with a method of cooking meat without browning first. So, you essentially braise the meat in a Dutch oven, you know, a 375 oven for a couple hours chop on maybe a cup of liquid, which could be tomatoes, it could be stock, take the top off and cook for another hour and a half or so depending on the meat. And the meat is above the liquid, at least some of it is and the heat of the oven will actually brown the oxtail without you doing any of the work at all. So, you get you know, the browning the maillard reaction, but you don't actually have to do it as a first step. I agree with you. oxtail is full of all sorts of wonderful things. Give you a nice rich broth, great flavor, and they're inexpensive.

Caller: Oh, that's great. So, 375 oven with the lid on for an hour, or for two hours?

CK: 350 or 375. Depends how much meat it is for a couple hours, about two thirds of the way halfway through cooking, just take the top off. And don't use too much liquid. So, the meat still is above the liquid. At least half of it is and then the heat of the oven will brown the meat. And it looks beautiful.

Caller: Okay, well, that's great. Because I don't mind the meat, the collagen and everything getting into the liquid. That would be great.

SM: But you did want them around it.

CK: You get a fabulous sauce this way. It's a great idea.

Caller: Oh, cool. Thank you very much. I'm glad you're cooking with stuff like oxtails you know the cheapest cuts of meat, are often the best

SM: and the most flavorful. Yes, thanks for calling

CK: Carol. Good luck.

Caller: thank you so much.

CK: Yeah, thanks.

SM: Bye. Welcome to Milk Street. Who's calling?

Caller: Hi, my name is Diana Peltor. I'm calling from West Des Moines, Iowa.

SM: How can we help you today?

Caller: I was making a quiche with my husband a few weeks ago. And we were wondering, is a quiche a pie?

SM: Oh, this sounds like there may be a disagreement between the two of you.

Caller: Yes, and we've agreed that you guys are the authority. And we'd like you to decide for us.

SM: Well, this is not based on a ton of research. But I'm going to say yes. It's a savory pie. Chris.

CK: Well, anything served in a pie crust is technically assuming there is a board of certification here is technically a pie, right? I mean, I mean, it used to be that pie crusts were made with flour, water, and they were never eaten. They were just a container right for cooking things in. So, you cook it and then just eat the filling. And then someone figured out how to make a pie crust you want to eat. So, they've always been pies. They're containers. So, I would say yeah, anything with a pie crust is by definition a pie. Right.

SM: So, Diane, who won? You are the husband?

Caller: Well, I'm so glad that you answered that way. And I'll be happy to let my husband know that a quiche is a pie. So, thank you so very much.

CK: Oh, good.

SM: All right. Oh, God, we love it when it's that simple.

CK: Sara, we should have asked her which side she was on first just to be sure

Caller: No, no, no, no, no, no, I didn't want to bias your opinion.

SM: No, no. This way she's got a stronger case. So, there you go. You go tell him.

Caller: I will right now. I will. Thank you. Bye. Bye. Thank you. Goodbye.

CK: This is Milk Street Radio. If you have a cooking question or need to resolve a culinary debate, give us a ring 855-426-9843. One more time, 855 426 9843 or email us at questions at Milk Street Welcome to Milk Street who's calling?

Caller: This is Sam from Franklin, Tennessee.

CK: How can we help you?

Caller: I learned how to cook from working in a home kitchen mostly by watching TV shows. Nowadays, I make bread a few times a week and we both enjoy it my wife and I but some of the recipes call for ingredients to be added at different times. And I was curious as to what that's about. I know in bread you put salt in and it will destroy the yeasts ability to grow and and do things but eventually they're together.

CK: Well, salt I once as somebody this question 20 years ago, I went to a bakery and he told me he didn't add salt right away because the salt would heat up the dough faster. And if the dough got too hot, it would kill off the yeast. So that was his answer.

Caller: Okay.

CK: If you read about this, the answer is what you just gave, which is that inhibits the action of a yeast which is also true, but that was his answer, which I thought was a pretty interesting answer. So that's why on the first round in a mixer or the food processor, you don't add the salt you lead Do rest 10 or 15 minutes and then you start up again with a salt. either answer is probably okay.

Caller: Okay, so it's just about, in the case of bread, it's about heat. But I've also seen it for baking. My wife has some baking, you know, we'll see where you do this. And even on your shows, we see where they put some ingredients in, they do some mixing, and then they put some more ingredients in.

CK: There's a lot of times where it makes sense. For example, if you take a typical Indian curry, they start with whole spices and oil, they get them going, and then they add some onions. And then they'll add ground spices later on. So, there's a whole method to the madness that his whole spices, the beginning ground spices later on, so you don't end up burning the spices. So very often, you're combining certain ingredients to develop flavor, then you move on to the next flavor development step. You know breads. For example, one good example is, before there was instant or rapid rise yeast, you had to proof the yeast, right? So yes, put in warm water, because there's lots of dead cells around the yeast and you have to dissolve those to activate these now is the yeast doesn't have that outer covering of dead cells. And that's why you can put it right in the flour. So that would be a good example of some recipes proofing yeast and some recipes, not

Caller: I put it right in right in the beginning. So, I have the flour in the bowl. I put the yeast on one side, I put the salt on the other side, and then I mix them together. And then I'll add the liquids.

SM: And what kind of yeast are you using?

Caller: I'm using the Frenchies.__.

SM: Yeah, that's good stuff

CK: I think that all of this stuff about adding the salt later, may come from commercial bakeries but in a home, it may not actually make much difference. So, we really should do an experiment here. We should try one with salt at the beginning of one the regular way. Maybe Sam's got a point.

SM: I think you should. Yeah, that would be interesting to know. It's good point.

Caller: I’ll watch your show to find it.

CK: And we'll give you credit, by the way. Yeah, it turns out you're right. Sam said throw that salt in right at the beginning

SM: Right in the beginning. Right.

CK: Thanks, Sam.

Caller: Well, have a great day, folks.

SM: You too

CK: Take care. You're listening to Milk Street radio. Up next, we're chatting with Dr. Arielle Johnson about the chemistry of taste and smell that are more in just a moment. This is Milk Street radio. I'm your host Christopher Kimball. Right now, it's my interview with Dr. Arielle Johnson. She's a flavor chemist and also a fermentation expert. Arielle, welcome to Milk Street.

AJ: Thanks so much for having me.

CK: Before we get into the Nordic Food Lab and fermentation boxes, and all this, what is flavor? Because flavor isn't just physical, it's emotional. So, could you talk about that?

AJ: Well, true flavor is physical and emotional. (Um) the way that I like to think about flavor is that there's a physical and molecular components. So, every flavor that you experience from food comes from molecules. But there's also a super important in fact, essential, neurobiological and emotional component. So, most of flavor is actually smell. And smell is a chemical sense. So, we actually have molecular receptors at the top of our nasal cavity that bind with small molecules. And then to actually experience smell and flavor those signals are passed to the brain where they pass through the emotional centers and are checked against all the memories we have of smell sensations we've had before. So, with flavor you actually experience your memories of similar flavors and your emotions connected to those before you consciously perceive the qualities of the flavor.

CK: So would an individual's specific emotions and memories of those emotions affect the perception of flavor. I would assume so right?

AJ: Oh, absolutely. With tastes sweet, sour, salty, bitter, and umami. We have a certain amount of Have hardwired responses to those. So we have a natural attraction to sweetness and positive feelings about it and a natural aversion to bitterness, since that's often a signal for the presence of poisons. With smells, most of it is kind of a blank slate. So it's up to us from babyhood to build sensory experiences around smells, and figure out if they are delicious and make us happy or dangerous and make us sad.

CK: Okay, so the Nordic Food Lab at Noma. What is it people actually do there?

AJ: Well, at the Nordic Food Lab, which was started by Rene Redzepi, the chef and founder of Noma in Copenhagen. And then later, when we started the Noma fermentation lab there, those spaces are really dedicated to experimenting with every ingredient that's available in the Nordic Region, as well as using the scientific method and literature reviews from all areas of science to understand how cooking and ingredients and flavors all work together.

CK: So, the goal of all of this was to end up with foods or fermentations, you could use he could use in the restaurant, or was there purely, let's have some fun laboratory and see what we could come up with?

AJ: Well, it definitely definitely started out as a Noma had this creative rule that the ingredients they were using in the kitchen had to come from Scandinavia. So that rules out Parmesan cheese, lemons, olive oil, a lot of other things that if especially if you're Western trained like a traditional French culinary school, you're very reliant on. So, the challenge became how do you get a wide variety of tasty flavors from limited starting ingredients. So it was actually not really possible to draw a line between doing things strictly practically and strictly for exploration, since they all ended up feeding into each other.

CK: So give me an example of something you did that worked out really well beyond your expectations.

AJ: I'm one of them was fermenting pumpkin seeds into me so so so so is a traditional condiment from Japan with roots in China that starts with a very enzyme rich mold fermentation on rice or other grants. And then, traditionally for miso, so soybeans are added to the multi grains, which are called Koji, and the starch degrading and protein degrading enzymes that the mold creates, go to work on the soybeans creating umami flavors, and free amino acids and sugars for further fermentation. So, some of my previous experience was that if you did this with very fatty ingredients, there was kind of this like oxidized paint taste, but the the pumpkin seeds had just the right balance of protein and fat that when mixed with us Koji had had this like amazing tropical fruit flavors that came out of it.

CK: Now, give me an example of something you thought was promising, but just you couldn't make work?

AJ: Something that I had trouble getting to work was fermenting blood. One gets into the mindset, I got into the mindset of there are these ingredients around, you should think about what the composition of those ingredients are, do they have starches or something that can be turned into starches? Do they have proteins? Do they have sugars? And then, you know, once you hit on something, you just start trying it out. So, blood is a protein rich, liquid. But when I was working with it, the the kind of livery metallic notes came out in a really extreme way. That was not pleasant.

CK: So bad idea. Let's talk about insects. I was speaking to Kim Severson from The New York Times who wrote a piece recently about the future of food. She thought that the insect excitement about eating insects would wane. You probably have very different point of view, I think you've noted that rain forest ants tastes like lemongrass, coriander and ginger, which is surprising. So, do you think that insects not just as a source of flavor compounds, but as a source of protein is something that's going to become part of a larger part of the human diet going forward?

AJ: Well, if you if you have looked into insect signaling, you'll find out as as we did, accidentally, that ants in particular use lots of flavor molecules called terpenes to communicate with each other and there's some of the same terpenes that are in fruits and herbs and spices. So, it was not super crazy to find that flavor although we weren't expecting it. But I mean, I think I think insects for protein is already is already happening. I mean, you have the XO bar, and other sort of protein meals and replacements. My hope my interest is more using ingredients like insects or any other sort of novel ingredient and finding a reallly delicious way to eat them. But the the sort of essentiality of macronutrients is inescapable. You're also proponent of eating trees.

CK: You're also proponent of eating trees. (yes) there are aroma and flavor powerhouses. So, what part of the tree are we eating and why?

AJ: Well, if you eat cinnamon, you're eating tree bark. So some some species of tree produce a lot of volatile and aromatic compounds in their bark, generally as an antifungal or an anti-insect defense measure that we find really delicious and cultivate and harvest and use of spices. But the twigs and branches and needles of evergreen trees also produce a lot of terpenes and delicious aroma molecules. Some of those have been traditionally used in brewing beer, but very young spruce tips are quite tender and acidic, those are the initial baby shoots that emerge in the spring that you can just pop those like a little piece of citrus. And then the more mature spruce and Douglas fir and pine needles can make a great seasoning actually either either steeped in vinegar, or if you blend them in a blender with about three times their weight in salt. You can have this really like exciting zippy, almost Juniper, like sort of referencing gin, but also distinctly piney seasoning.

CK: Wine and smoke. This was really Oh, yeah. So could you just talk about that, because I don't quite understand it's a good magic trick. Give me an explanation of what's going on. And why

AJ: Well, in the last 10 to 15 years because of climate change and increases in summer temperatures. We started seeing in Australia, and then eventually in California wildfires. And so, what winemakers were seeing was that after a wildfire, their grapes smelt very smoky. And sometimes the smoky aroma would go away for a little while. So, they would press the grapes get the juice and fermented into wine, but then it came back. So, the smoke somehow worked its way into the grapes in a way that was much, much deeper than just depositing on the outside. And eventually what some Greek biologists and flavor chemists figured out was that the grapes were actually absorbing the smoke volatiles, using endogenous enzymes to attach sugar molecules to those aroma molecules, which was locking them away in a senseless form. But then, when the grapes were fermented, yeasts have a lot of enzymes to undo those bonds, which is why generally, wine aroma increases as it's fermenting. So, these smoky smelling molecules that were locked away by the grapes were liberated by the yeast and the smoke would come back. So, this is this is called smoke taint. And it's an increasing economic and wine quality issue that a lot of people are focusing on.

CK: Are there some things you think home cooks or bakers in particular maybe should know about food science that would be helpful to them in in cooking or baking at home?

AJ: Oh, definitely. I mean, for bakers. If you're adding seasonings or like garnishes to pastry, it's helpful to understand at a super basic level that tastes molecules like sweet, sour, salty, bitter, and umami are mostly water soluble and smell molecules, which is basically everything else. So, like fruitiness citrusiness, spiciness, herbal notes, those are all more soluble in alcohol and oil. So, if you're trying to express a certain flavor of an ingredient like coffee beans, it will be more bitter and acidic if you make an extraction of water and then incorporate that if you want to just have the aromas of coffee, making a coffee butter or a coffee cream or a coffee tincture is a way to get that while avoiding bitterness.

CK: These are excellent. You got an A on the test. I just want you to know, that was very clear to the head of the class,

AJ: I feel like I'm back at my qualifying exam for my PhD

CK: Well, it’s a scientific process which hopefully ends up with something good to eat

AJ: Exactly.

CK: Arielle, it's been a pleasure and it's been fun having you on Milk Street.

AJ: It has been so fun talking to you, Chris. Thank you.

CK: That was Dr. Arielle Johnson. She's a flavor chemist and the science officer on the reboot of Good Eats. Her forthcoming book is Flavor Rama, the unbridled science of flavor and how to get it to work for you. neuro gastronomy is the scientific study of the brain and flow So here are some interesting facts. It turns out that the weight, color and texture of the glass or cup you used to drink from has a very large impact on your perception of the contents, including freshness and pure pleasure. Studies have shown that if two cups have the same volume, the taller one is perceived as having more. For example, a tall champagne glass looks like it holds more than a round wine glass. Other studies have shown that plastic containers are perceived as holding more volume than glass, and people will consume more of a product if they perceive the package to be larger. In short, what we eat and drink from may have more impact on our enjoyment of food than the food itself. So once again, it's mind over matter. Right now, I'm heading into the kitchen and go straight to chat with Lynn Clark about this week's recipe Spanish almond cake. Lynn, how are you?

Lynn Clark: I'm great, Chris.

CK: So, we're talking about flour-less cakes today. But this is an almond cake, not chocolate, which of course is that 1980s standby in every restaurant. Yeah. And this comes from Spain. So, is this a traditional recipe in Spain?

LC: It's a traditional recipe in a region of Spain called Galicia. We went to a bakery there called Casa Mora. It's called the torta de Santiago. It's flourless almond cake. Really simple one bowl cake. If I were to describe it, I would say it's almost like if you took a French macaron and made it into a cake, it has kind of chewy, but dense texture. But somehow the density is not leaden it's kind of a light dense if that makes sense.

CK: Well, macaroons are light, dense. Exactly. I'm kind of light dense too so this is the perfect cake for me. So you said, it's a one bowl cake. So how do you make it?

LC: So traditionally made with whole eggs, we found we couldn't get the lightness we wanted from whole eggs, we tried separating the eggs, so whisking egg yolks with sugar, and then whipping egg whites separately, it was really hard to incorporate the whites into this space, the space is really really thick, almost like playdough with the almond flour in it. So, we couldn't really get the whites to really give us the lightness we were looking for. So, we tried something interesting by using whole eggs, and then just adding extra egg white. So that allowed us to incorporate that air we wanted, but kept it really simple. All in one bowl

CK: Is it baked in the cake pan or springform pan, how do you bake it?

LC: So first we mix those eggs together with sugar, almond extract, vanilla extract, salt, and then you whisk that really vigorously for about 45 seconds. And then add the almond flour. It goes into a cake pan just a nine-inch prepared cake pan and we top it with a combination of chopped almonds and turbinado sugar that creates sort of a crispy crust on it. Some of these historically are baked with an actual crust like a shortbread crust. So, this was our way to mimic that. it bakes for about 15 minutes or so.

CK: And then you take it out you let it cool you stand around you want to eat it, but you have to wait.

LC: You should let it cool completely. It's a really good idea. It's a different texture, warm and cool.

CK: So a Spanish almond cake. It's flourless, it's a one bowl cake. just bake it into cake pan. It's a macaroon in the form of a cake. Thank you.

LC: You're welcome. You can get this recipe for Spanish almond cake on 177 Milk Street com.

CK: You're listening to Milk Street Radio. Coming up we'll hear from J Kenji Lopez Alt about the real meaning of food expiration dates. We'll be right back. This is Milk Street Radio, I'm Christopher Kimball. Next up Sara Moulton and I will be taking a few more of your cooking questions.

SM: Welcome to Milk Street. Who's calling?

Caller: Hi, this is Greg.

SM: Hi, Greg. Where are you calling from today?

Caller: I'm calling from Highland New York.

SM: How can we help you today?

Caller: With all of my spare time which I have a lot of now. I've been experimenting with bagels. The issue that I have is that I prefer sourdough. You know to me it's just it's just a better flavor than a yeast bagel but you know, it's time consuming. And I don't want to have to wake up at like three in the morning to get them going. So, what my approach was, is that I would make the dough and I'd stretch it and folded it as I do with my breads and things and then I would shape the bagels and boil and bake them the next day, but without the basket because they use baskets for my bread and that comes out well, they kind of wind up like hockey pucks, instead of bagels. I put them in the fridge overnight. I got to do that though the day before. So, I'm looking for suggestion kind of had a climate so that I could do the sourdough aging and such the day before and then bake it the next day.

SM: You're going to want it in time for breakfast is what you're saying.

CK: But I think most or a lot of bigger recipes do exactly what you do. They make the dough, they shape it, they let it sit in the fridge overnight, they boil and then they bake it the next day. I mean, I don't think that's unusual. I've seen a lot of recipes to do that exactly.

Caller: I'm not getting any spring. Like it's like they're like these are tastes really good but they're so flat, which I don't have with bread, you know, so it's weird.

SM: Well, how much of a resting time do they have? You make the dough and you said you shaped them into the rounds before you put them in the fridge overnight? Is that correct? (Yeah) And then the next morning, you take them out? And do you let them come to room temperature before you boil them?

Caller: I haven't been.

SM: I wonder what do you think Chris?

CK: There is a method. It's on Serious Eats, which I go to a lot where they use a Japanese method where they cook flour water in a skillet. Let it cool. And then they use that when they go make the dough as a base. It gelatinizes the flour and it keeps them moister or you know better the next day. I don't know if that solves the problem of holding the shape. But I think it would give you a softer, less of a hockey puck. I'm no expert on bagels, but that's the one that really stuck out to me as being kind of interesting.

Caller: So, you cook the flour,

CK: You cook a small part of the flour, (okay) with water, you cook it in a skillet, briefly. Let it cool. Maybe have a couple of cups of flour or a cup of flour and use that as a base. And then then when you go ahead you add that to the dough when you're making the dough. (Interesting). And that is a Japanese method for turning out a very soft, moist bread. (Interesting) and that might give you a better texture.

Caller: Yeah, I definitely would like to try that. I recently went to Japan and I noticed that a lot of their breads are soft and moist. So, I wonder if that's what I'm seeing when I was there. That's interesting. Go to Syria seeds.

CK: Go to Serious Eats and check it out.

Caller: Yeah, I'm going to try that. Thanks, Chris. Thanks Sara Take care.

CK: Okay,

SM: bye bye.

CK: This is Milk Street Radio. If you have a cooking question, give us a call the numbers 855-426-9843 one more time at 855- 426-9843 or email us at questions at Milk Street Welcome to Milk Street who's calling?

Caller: Hey, Chris and Sara. It's Lori calling from Denver, Colorado.

CK: How are you?

Caller: Good. I am actually calling you back. I inquired about banana peel. Four months ago.

CK: You were the banana peel lady. I remember I remember this. Yeah. So what did you do with them?

Caller: Sara recommended banana peel bacon. That was a bit of a dud if I’m being honest

SM: Darn I was so excited. I was getting ready to do it myself.

Caller: I mean, it was okay. Not great. And then I actually made banana peel chutney.

CK: Oh, that's a good idea actually

Caller: I thought it turned out great, really great flavors, but now I'm at a loss of what to do with that chutney. To me, it just it's too sweet for a savory dish.

CK: A couple ideas. I buy a tamarind chutney and put that with softened butter and mix them up. Maybe two parts butter to one part chutney and I put that on a warm bread like a flatbread and use that as sort of hors d'oeuvres or you know, with drinks. And so, you can make a flavored butter with it. The other thing I can think of is put a chutney on a roast chicken, but not at the beginning sort of towards the end of roasting. Just as a way of adding some flavor on the outside of course not the inside. And that's a pretty good trick too. I mean, those are two things I can think of Sara

SM: Well I'm just wondering if maybe you need to doctor it if you say it's too sweet. And things that I might add to it would be a little more acid. You know, it could be simple as lemon juice or maybe a vinegar and or some chilies. The chili will really tamp down the sweetness. And I think that would help a lot to just make it less sweet to put it on goat cheese for example, you know a cracker with goat cheese little chutney on top or I liked the thing that Chris suggested with putting it on top of chicken, you know again add mustard, add chilies, add lemon juice, and all the things I just said you could add to it will not make it any less shelf stable.

CK: Or you know our editor JM Hirsch is a cocktail guy, and he just did a little video about adding jam as a way of sweetening cocktails instead of sugar syrup. For flavor, you could add a tablespoon to the mix. I also find chutneys I use it all the time on when I make sandwiches. I find something on one half of the sandwich is slightly sweet. And then I have something spicy like harissa and the other bread. One side something spicy one side something sweet. It would be a great way to you know spice up a sandwich to

SM: a grilled cheese sandwich.

CK: Perfect, actually very good idea.

SM Anyway, you're a soldier. Thank you for sharing this with us.

Caller: It's been such a fun time doing it and hopefully I'll see a recipe for banana peel chutney on Milk Street sometime soon, right Chris?

CK: Yeah, but you're not going to see a recipe for a banana peel bacon any time soon, I’ll tell you that

SM: Oh come on Chris just humor me

CK: Anyway good job. You persevered and came out thanks for calling

SM: Thank you very much. Bye bye.

Caller: I appreciate it, bye bye

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

Caller: Hi, this is Mindy from Flagstaff, Arizona. My cooking tip is brush a steak or a salmon filet that you're about to pop on the grill. Brush it first with oyster sauce. It gives it an amazing lacquered caramelization and a je ne sais quoi that people have no idea what makes this steak or piece of grilled fish different. But it usually garners rave reviews. Enjoy.

CK: If you'd like to share your own cooking tip on Milk Street radio, please go to 177 Milk Street .com slash radio tips. Next up, it's food science writer j Kenji Lopez Alt. So, Kenji, what have you been thinking about this week?

J Kenji Alt: Well, I recently wrote this article for the New York Times about expiration dates. So I've been thinking about that, because expiration dates are one of those things, you know, I, you know, my mom largely ignored expiration dates when we were younger. So sometimes I would come in and find, you know, orange juice that had expired a month in the past, or certainly spices that that had been sitting there for 12 to 15 years. In fact, she probably still has some of the same spices she had when I was a kid. And then, you know, as I became sort of like a teenager, I started thinking and telling my mom, you know what, this is kind of gross, I'm going to go through your fridge and just start throwing these things away. And I did that. And now as a as a, as a father, myself, I mostly ignore the expiration dates again, because I had always thought they were about food safety, about whether the food was fit to be eaten or whether it would make you sick, right. But then it turns out that it's not, that's not what they're about at all. In fact, they have nothing to do with food safety, so that the only food that is required to have an expiration date on it is baby food, everything else is there voluntarily. And it's there as sort of a manufacturer's best guess, as to when the food is not going to be at peak quality anymore.

CK: Let me just stop you there. If they're not required to put an expiration date on, which means that a lot of foods would not be returned from the supermarket, because it's since no one knows what the expiration date is, aren't they losing millions of dollars for something that's not actually required by the federal government?

JKA: Well I mean, a food manufacturer, you know, if you're buying, you know, you see four different brands of milk, and one of them doesn't have an expiration date on it, and you buy it, and it turns faster than you expected, then I would just stop buying that brand of milk, you know, I think they, I think they do have something to gain by predicting when their food is going to actually taste good. But you know, the thing is that most foods will actually last well past their expiration date, because that expiration date is really just a guess about best quality. And of course, you know that that guess is really it's it, that's what it is, it's a guess, because they can't tell exactly how the food is going to be shipped, how it's going to be stored, whether someone carried it around the supermarket, and then decided to put it back on the shelf, you know, and then once you get it home, of course, they don't know how how you're storing it at home, you know, whether you're drinking the milk out of the carton, or whether you're, you're opening up the jars with dirty hands, etc. So, it's really, really difficult to actually predict how food is going to behave once it leaves the factory. So usually, those estimates are actually pretty conservative. So, if you're treating your food Well, it's probably going to last well beyond the expiration date does.

CK: So you mentioned something interesting. You said whether you drink out of the bottle or your head dirty hands when you open the jar. So, introducing bacteria into a container that you just opened that could have a substantial impact on the longevity of that food.

JKA: Oh, absolutely. Yeah. So let me give an example. I got my restaurant we go through a lot of cheese and we you know, we get giant blocks of it and then we grade it on So that's one of the things where we require gloves because we know that if you grate cheese with bare hands that you've just washed versus grated cheese with, with gloves on, it'll last for like, weeks longer, like you'll start to see, you'll start to see molds sooner. And I did this little experiment at home with my daughter, where we bought a package of grated cheese from the supermarket. One handful, we picked up with just her hands before we washed them. Another handful we picked up after carefully scrubbing her hands. And then the third one we picked up with gloves on our hands. And then we put them in containers and stored them in the fridge and the one that you that you touch without washing your hand obviously starts to mold weeks before the other two. And gloves is the longest but but yeah, absolutely. So, milk, for instance, especially if you get like the UHT milk, ultra-high temperature pasteurized milk that milk is is heated to 250 degrees Fahrenheit, which is hot enough not just to kill bacteria and viruses, but actually destroy spores as well. And then it's pumped aseptically into containers and sealed. So, it should be completely sterile in there, which is why it lasts for months and months. So, there's nothing really going on in there until you open it and then bacteria from your mouth from the air. That's when bacteria start to get in. And that's when the sort of the clock starts ticking on when it's going to go off.

CK: So what about eggs? You know, I've heard all these rumors about eggs being older than they say. I mean, what's the deal with eggs? The French used to keep eggs on the counter. They never refrigerated them, right?

JKA: Yeah, well, they still do that in lots of parts of Europe. You know, the reason they do that is because when the US eggs are washed, and that sort of removes is that waxy cuticle surrounding the egg. So, you then have to refrigerate them because it makes them more air permeable and makes them more permeable to bacteria and viruses. Whereas in Europe, they don't wash them before selling them. So, you know, it's sort of like in one case, they're dirtier or when you buy them, but you don't have to refrigerate them. Whereas in the US they're cleaner when you buy them, but it's then easier for them to get reinfected. So is this sort of a trade off? That's right, that's right, that trade off?

CK: So so how old are eggs when you buy them? And how long do they last, you know,

JKA: In most parts of the country eggs, the expiration date that they get on them is 30 days after they were packed. And usually, they can be packed up to 30 days after they were laid, although in most cases, they're probably getting packed actually, like the day off or the day after they're they're laid, which means that, you know, if you add those numbers together, you get about 60 days as your lifespan for for an egg in refrigeration. And that's of course, just the sort of, you know, the peak quality level there in reality, they're probably going to last a month longer than that, you know, 90 days is not unreasonable for an egg to last.

CK: Are there any foods other than dairy products where you should be really concerned about expiration date versus other foods?

JKA: Well, there's there's none that I would really look exactly at the label, you know, other than just as a loose guideline, you know, I think using your nose and your your senses is the best way to tell if something's off. And of course, you know, when in doubt, throw it out, you know, things where you should be worried where that that can actually get you legitimately sick are canned goods and jarred goods where you know, if it can is bulging, or if it shows any rust is that's an indication that there might be bacterial action going on inside or that the seal has been contaminated so liquid is coming out and rusting the exterior, or with a with a with a glass jar with a screw top, if the buttons popped up, that means that there's probably some kind of bacterial activity going on inside and that's the kind of stuff you want to really be careful with. But you know, other than that, things tend to last a long time you know, spices for instance, you know, I said I went to my mom's house and I'm sure she has spices that are 35 years old from when I was a kid. Those spices are probably not going to kill you they most likely they're not going to taste like anything, but they're probably also not going to really harm you to eat it

CK: But I've had I'm going to push back so sure my mother you know, had the same spices she bought I think when she first got married after the Second World War and those were tasteless but I got some spices from what trip once North Africa and three or four years later some of that stuff was still really pungent so he is the six month rule or one year rule really a good rule of do a well preserved you know fennel seeds or something like that actually last and are fresh a long time

JKA: Oh yeah I mean it all has to do with how you store it and the state at which you buy the spices so you know it's a whole spices will last a lot longer than ground spices just as ground spices have more surface area for you know the aromatics to jump off from but yeah it i mean if you seal it you know if you especially if you like vacuum seal your spices or you put them into jars with really tight screw tops and you keep it in a in a pantry. You know, it's the same basic rules that I think most of us know which is like you know, light, heat and air are the enemies of freshness for pantry ingredients. One thing to note in your pantry though, is that with grains whole grains don't last quite as long as more refined grains so whole wheat flour will go off right before white flour does and this because of the fat that those contain, that tends to go rancid. So yeah, and but you know it's something that you'll smell before that you should be able to pretty easily smell it. It gets like a kind of soapy metallic smell to it, you know

CK: And cooking oils also. I know get very fishy. If there's any odor coming off of your cooking oil, then you've got a problem, right?

JKA: Yeah, if it smells fishy, or smells soapy, then for sure. And also touch wise, like if you if you put a little drop of it on your finger, it should feel slick. If it starts to feel sort of tacky or sticky, then that's an indication that also that is probably gone rancid. And you know, and again, that's probably not going to kill you to eat it. It's just not going to taste very good. And it's not going to behave in the way that you expect it to.

CK: So, expiration dates are not about food expiring they're about when food is at its peak, which is a very different thing. So next time I get a bottle half and a half. I'm still going to look at the expiration date. Because that yeah, I find that stuff really does go bad. But a chocolate bar, maybe not. Yeah, thank you, Kenji.

JKA: Thank you.

CK: That was j Kenji Lopez alt. He's the chief culinary consultant for Serious Eats. A food columnist for The Times also author of the Food Lab. The fact that expiration dates are relatively meaningless makes me think of some other perfectly useless product labels. Here are some of my favorites: on peanuts may contain nuts, on a shoe box average contents two, on a superman outfit does not enable where to fly. And in a car manual, it says in order to get out of car, open door, get out and then close doors. So, what's next? usage labels on bananas. That's it for today. If you tuned in to later, just want to listen again. You can download and subscribe to mostly radio on Apple podcast, Spotify, or wherever you find your podcast. To learn more about Milk Street please go to 177 Milk Street com there you can download each week's recipe. Watch the latest season of our television show or order our new cookbook, Milk Street Fast and Slow, Instant Pot Cooking at the Speed You Need. You can also find us on Facebook at Christopher Kimball's Milk Street now on Instagram and Twitter at 177 Milk Street. We'll be back next week 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, co-executive producer Annie Sensibaugh. Associate Producer Jackie Novak, production assistant Sarah Clapp and production help from Debby Paddock. Senior audio engineer David Goodman, additional editing from Vicki Merrick Sidney Lewis and Samantha Brown. And audio mixing from Jay Allison at Atlantic Public Media in Woods Hole, Massachusetts. The music by Toubab Krewe. Additional music by George Bernard Egloff Christopher Kimball's Milk Street Radio is distributed by PRX