The Calculus Around You

In her new book The Calculus Diaries, writer Jennifer Ouellette describes the development of calculus, from Archimedes to Newton, and shows how calculus is a part of everyday life — from amusement park rides and Vegas craps tables, to dieting and figuring out gas mileage.

NEAL CONAN, host:

The food truck has long since traveled from the West Coast to the Northeast, now to the Midwest. The deliciousness inside these mobile kitchens covers everything from tacos to Japanese-styled crepes - more on that in just a moment. And you know it's a trend when there's a reality show attached to it. "The Great Food Truck Race" airs every week on the Food Network here in Columbus. The food truck trend arrived 10 years ago, though it exploded about a year ago.

Bethia Woolf is here to guide us through it. She's a food writer and founder of Columbus Food Adventures, at the studios of WLSU. Nice to have you with us today.

Ms. BETHIA WOOLF (Founder, Columbus Food Adventure): Thank you.

CONAN: And we want to hear from those of you in our audience as well. What gourmet food are you eating out of carts and trucks where you live: tacos, crepes, noodles? 800-989-8255. Email us: talk@npr.org. You can also join the conversation on our website at npr.org. Click on TALK OF THE NATION.

So Bethia Woolf, this trend, 10 years ago?

BETHIA WOOLF: From what we've been told, the first taco truck opened in Columbus about 10 years ago. And I think, for a few years after that, there was just a very small number of taco trucks in Columbus. And now, there are approximately 40 taco trucks. But in the last year is really when we've seen or even just this year, 2010 is when we've really seen an explosion of the, you know, what people called the gastro trucks and carts.

CONAN: The gastro trucks. That's a good thing, not a bad thing.

Ms. WOOLF: Oh, it's a great thing.

(Soundbite of laughter)

CONAN: The taco trucks, were they servicing primarily the Hispanic communities?

Ms. WOOLF: Yeah, predominantly. And we started the website, tacotruckscolumbus, in the spring of 2009. And we've seen a lot more non-Hispanic people eating at the taco trucks partly as a result of the website and some of the media attention that the website has had.

CONAN: And you sponsored taco truck tours.

Ms. WOOLF: We did well, we started a company this year to start offering taco truck tours. A lot of people will read about the trucks on the website and that's enough that they want to go try it. Some people need a little bit more encouragement. Maybe, they're a little intimidated if they haven't been to the trucks before, so we take guided tours.

CONAN: And do you arrange with the truck owners to be at a certain place at a certain time?

Ms. WOOLF: Yeah, yeah. We have arrangements with all the trucks. We visit on an average tour, we visit five trucks.

CONAN: And it used to be in the lunch cart industry that they would park themselves out of the outside of the factory gate or some place they knew that people would be coming out hungry at a certain time of day. Is that the way this works broadly?

Ms. WOOLF: The trucks in Columbus are a little bit different than the way the trucks operate in Los Angeles. In L.A., the trucks have to move around, I think, every hour. In Columbus, they generally have a set location. The taco trucks have a set location, and people will go to them. And we have a map on the website showing where they are, so they're a little bit different. The newer carts and trucks tend to be much more mobile. And they're the ones that are using social media and people are going to track them down.

CONAN: So they can get the location on Twitter or on Facebook or something like that.

Ms. WOOLF: Yeah. Mm-hmm. Mm-hmm.

CONAN: And do the does the chamber of commerce, the restaurants who are members of that, consider these people a threat to their livelihood?

Ms. WOOLF: So far, it doesn't - we haven't seen any sign of that. And actually, some of the restaurants in town are actually starting to open their own carts and trucks, partly as a marketing device and partly because they want to, you know, capture some of that market themselves.

CONAN: You mentioned taco trucks were the basis of this industry, but that it had exploded into what, for example?

Ms. WOOLF: We have trucks that offer everything from cupcakes, Cajun food, barbecue, pizza, even because we're in Columbus, we have to have buckeyes on a stick. So there's a cart that specializes in buckeyes.

CONAN: Hmm.

Ms. WOOLF: But everything, vegetarian food, breakfast pizzas. It's a really wide range of food.

CONAN: One of the carts you've mentioned, the Foodie Cart, sells Japanese-styled crepes. And it's parked in the Short North here. That's a neighborhood in Columbus, Ohio.

Ms. WOOLF: Mm-hmm.

CONAN: And we've got the owner, Kenny Kim, on the line. Kenny, are you with us?

Mr. KENNY KIM (Co-owner, Foodie Cart): Yes, I am. How's it going?

CONAN: It's going very well. We wanted to ask you the same question. How's it going?

Mr. KIM: It's going great. Today, we kind of set up at a weird time, so it's a little slow right now. But it's so beautiful outside that we are just happy to not have cold rain or, like, super-windy conditions or a hundred degree weather. So yeah, we're okay.

CONAN: And that must play a big part in your calculation of how much food you order and manufacture every day.

Mr. KIM: Well, our cart is really small. So we don't have that problem of kind of overbuying things, because, you know, once we sell out, we -or if we don't sell out, we don't have that much food left over like -as opposed to, like, a restaurant if (unintelligible)...

CONAN: How did you...

Mr. KIM: Oh, go ahead.

CONAN: I was just going to say, how did you get started in this business?

Mr. KIM: I was working at a restaurant and my wife was working at a restaurant, and we pretty much both switched restaurants jobs a lot. And it seemed like kind of the same pattern, and we wanted kind of give our own ideas and share them with customers. And the cart was basically the only way we could do this. And I just fell into some luck and found a cart for cheap. And right when we started, Columbus was really into food carts, and the timing for us was just perfect.

CONAN: And Japanese-style crepes. What kind of crepes are you serving today?

Mr. KIM: Today, we have bulgogi cheesesteak, which is a Korean marinated beef cheesesteak. We have a chicken ginger, chorizo avocado, we have a bacon okonomiyaki, an Italian trio with egg and cheese, which is like prosciutto, salami, capocollo, baby arugula or baby spinach, stuff like that. We have a green veggie egg. We have a tempeh stir fry for vegan customers. And then we have two dessert crates today. One is the Kabocha Mont Blanc, which is Japanese winter squash, baked meringue, fresh whipped cream and a little saucy caramel. And then we have azuki stick with strawberries, which is Japanese sweet bean with sliced strawberries and mozzarella cheese in, like, a stick form. So a little different crepe format on that one.

CONAN: And you're telling me this is a small cart? And it sounds about the size of a Howard Johnson's.

(Soundbite of laughter)

Mr. KIM: Well, it is really small. We just - I mean, we both have a lot of restaurant experience, so we know how to maximize space and, you know, just be - you got to be super organized to, like, do all that stuff on a little cart. But, yeah, you just have to plan it out well.

CONAN: Well, good luck to you. And what happens when - you know, it has been known to get cold here in Columbus come wintertime.

Mr. KIM: You know, this is our first season, so we're trying to figure that out right now, too.

(Soundbite of laughter)

Mr. KIM: We'll see. A couple of options are to link up with another business that doesn't utilize their kitchen, or there's some indoor markets going on in the wintertime. Those are some of the main options. For us, I don't know how hardcore we are about standing out in the cold. I know some carts and trucks do that. I don't know if we're as strong as them about standing out in the cold like that, but maybe we'll do it for a little bit.

CONAN: Kenny Kim, we...

Mr. KIM: Well, I feel like people don't want to - I don't know if people are going to want to come out if it's that cold, anyway. So we're figuring it out as we go.

CONAN: They might ask you if you've got hot chocolate and then move on if you don't. Kenny Kim, good luck to you.

Mr. KIM: Thank you, sir. Appreciate it. Bye.

CONAN: Kenny Kim runs the Foodie Cart, parked today in Columbus' Short North District. And Bethia Woolf, is he typical of the new kind of foodie you're talking about?

Ms. WOOLF: He's definitely - I think they're probably more on the cutting edge, that they are really creative with their menus. And as you heard, they have a lot Korean and Japanese influences, as well as kind of playing around with all sorts of different flavors.

CONAN: Well, let's see what people in our audience are eating out of food carts. 800-9898-255. Email us: talk@npr.org. Rosemarie's with us from San Antonio.

ROSEMARIE (Caller): Hi.

CONAN: Hi, Rosemarie. You're on the air, go ahead.

ROSEMARIE: Yes. Basically - well, of course, (unintelligible) in San Antonio, it's always the Mexican, taco chucks, you know, the mini-tacos and all sorts of Mexican food. But lately, we've had a couple of trucks that have been Indian food or Turkish food. So we're starting to branch out more.

CONAN: Indian and Turkish - are there large Indian and Turkish communities San Antonio?

Ms. WOOLF: No, not that I'm aware of. There really isn't. I guess maybe they're just trying to get some diversity.

CONAN: And when you go the Turkish food truck, what do you order?

(Soundbite of laughter)

Ms. WOOLF: Actually, I haven't been able to find it. It moves around to different places, and I haven't been yet. But I'm trying to get to it.

CONAN: All right. Thanks very much, Rosemarie. Good luck.

ROSEMARIE: Thank you.

CONAN: Bye-bye. Let's see if we can go next to - this is Brian, Brian with us from Nashville.

BRIAN (Caller) Yes.

CONAN: What kind of food do you eat out of a taco truck or a food truck?

BRIAN: Oh, well, my favorite food truck here is actually a taco truck. It's a gourmet taco truck called Mas Tacos Por Favor.

CONAN: And which particular variety do you prefer?

BRIAN: They have a cast-iron chicken, which is delicious. They do it with tomatilla salsa and some fresh cilantro and some sour cream and lime juice squeezed over. And it's just fantastic.

CONAN: Cast iron, presumably referring to the method of it's being cooked as opposed to the kind of stomach you need to eat it.

BRIAN: Right.

(Soundbite of laughter)

CONAN: Thanks very much, Brian.

BRIAN: Okay. Thank you.

CONAN: Here's an email that we have from Leslie in Upstate New York: Oh, please, America's just catching up to New York City, where as a young exec I went to the falafel truck in Rockefeller Center almost daily back in the 1970s.

Bethia, have you been able to trace this trend back further than that?

Ms. WOOLF: I haven't really, in terms of the ethnic foods, looked into it like that. There's obviously a very long history of hotdog carts and kind of some of the more traditional street food.

CONAN: But in terms of offering more exotic fair, is this a West Coast phenomenon that came East? Or did it spontaneously arise in many places all at the same time?

Ms. WOOLF: I'm guessing that you can find people from L.A. and New York who would like to lay claim to the origins of that.

CONAN: Maybe they could duke it out in the neighborhood of Lincoln, Nebraska, somewhere. Let's go next to - this is Leticia(ph), Leticia with us from Charlotte.

LETICIA (Caller): Hi, I wanted to share with your listeners about food trucks that we have here in Charlotte that's serves only locally produced food.

CONAN: And what are they?

LETICIA: It's the Harvestman trailer. They were started by the children in Grateful Growers. This is a farm that mostly does pork...

CONAN: Mm-hmm.

LETICIA: ...but they actually work with many different farms in the area. They even have a map every week, showing you where the food on today's menu has come from, and shows you where all the farms are in the Greater Charlotte area.

CONAN: So not merely a map showing where they are going to be, but a map showing where the food originated so you can feel secure that it is locally origin.

LETICIA: Exactly.

CONAN: All right. Leticia, thanks very much. Appreciate it.

LETICIA: Thank you.

CONAN: Bye-bye. We're talking about the food truck business, taco trucks that a lot of people are familiar with, and more exotic fare as well. Our guest is Bethia Woolf, a food writer who runs the Taco Trucks Columbus offers small group tours of the various delights to be found on food trucks in the city. You're listening to TALK OF THE NATION from NPR News.

And, Bethia, as you go through these various kinds of things, clearly telling your customers where you are is really important.

Ms. WOOLF: Yeah. I think telling the customers where you are, having a good location, is important. But obviously, the food that you offering is what's going to get you to repeat business and make you - people follow you all over the city wherever you happen to be.

CONAN: Let's go to - let's see if we can go to Elise(ph). Elise with us from Charlottesville in Virginia.

ELISE (Caller): Hi. How's it going?

CONAN: Very well. Thanks.

ELISE: I'm calling because I have a weakness for hot dogs. And there's a wonderful truck around here called Last Call Dogs. And they do organic hot dogs. And sometimes they throw some from Joel Salatin's farm, which was made famous in "Omnivore's Dilemma." So it's wonderful hot dogs with excellent toppings, and I love it. It's - I can't find the truck all the time. But when I do, it's wonderful.

CONAN: Elise, I have to confess, I worked a number of years in Minor League Baseball, after which I vowed I would never eat a hot dog again.

ELISE: Oh, well, this is different, because this is a different kind.

(Soundbite of laughter)

ELISE: But I agree with you.

CONAN: A bratwurst and Italian sausage, they're fine, but something that calls itself a hot dog, I'm terribly sorry.

ELISE: Okay. Well, thank you.

CONAN: All right. Elise, thanks very much. Charlottesville, obviously a college town - well, not unlike Columbus, Ohio. That would seem to be a major factor if you've got a bunch of hungry people in their late teens and early 20's.

Ms. WOOLF: Yeah. They definitely have some trucks on campus as also we get trucks downtown at lunchtimes. But Columbus - the trucks are spread all across the city. The Mexican taco trucks tend to be more out on the west side of town, but they're really spread across the whole city.

CONAN: Is that the Hispanic community?

Ms. WOOLF: Mm-hmm. A concentration of it.

CONAN: Now, let's go next to - this is Bernard(ph). Bernard with us from Truckee in California.

BERNARD (Caller): Hi, guys. I'm sitting here eating my Indian fusion food right now, from the red truck in downtown Truckee, California.

CONAN: And what particular - what are you having for lunch?

BERNARD: I'm having tikka masala with some dal, and these guys are great. They do local ingredients, organic, sustainably raised stuff, and it's delicious. We love it.

CONAN: And to - and these are wonderful foods, but they can be messy. How do they serve it?

BERNARD: Well, I got it in a bowl, but they also serve it taco style, burrito style. They're really creative with what they're doing - the gentleman who started it is a classically trained chef, went to the culinary institute in Vermont. And he's real creative about when he's putting together here. It's really exciting for a small town like Truckee, California on the north shore of Lake Tahoe.

CONAN: Well, thanks very much. Enjoy your lunch.

BERNARD: Thanks a lot.

CONAN: Bye-bye. And Bethia Woolf, delivery - well, not just knowing where they are - but the hot dog originated because it was a bun, you can put a piece meat inside of it and it was easy for somebody to have and not make a mess out of themselves. I guess the advent of the Styrofoam bowl has made things a lot easier.

Ms. WOOLF: Yeah. We see a big variety of foods. We have - even have a cart that sells soups, so it's - you know, it's not just kind of things you can hold in your hand. With the hot dog, we used to have a Mexican hot dog truck in Columbus last year. I don't know if you've tried them.

CONAN: I've not. You know, if it said hot dog, I didn't try it. Let's see if go next to Jackie(ph). Jackie is on the line from Milwaukee.

JACKIE (Caller): Hi. How are you?

CONAN: Go ahead, please.

JACKIE: I'm the operator of a brand-new food truck here, called the Fast Foodie. And what we do, similar to what your guest, Bethia had talked about being creative with their menu. What we offer is called a Globaco. Nobody else from the country is doing this. It's short for global taco, and we have trademarked this. And we take global food from all around the world, anywhere from Jamaica to Puerto Rico, Korea, and put it in a taco to make it portable and allow people to eat it on the streets.

CONAN: And how is it going?

JACKIE: Oh, fabulous. We've just launched about three weeks ago. And we are all over the city as well as in different office parks throughout the greater Milwaukee area. And we have had tremendous feedback so far.

CONAN: And so you're - clearly hoping to take the Globaco to the world.

JACKIE: Oh, absolutely.

CONAN: And what particular varieties are going well, do you think?

JACKIE: Probably our three biggest sellers, we have one called Jamaican Me Crazy, which is a Jamaican curry beef dish. I have one called Hahny Hahny, which is named after my best friend in the world, who's from Seoul, South Korea, so that's Korean barbecue. And we've got one called the Big Sexy, which was named after my friend, Rick Rodriguez(ph), who is Puerto Rican and it's a family dish of his.

CONAN: Jackie, good luck with globaco. And thanks very much for the call.

JACKIE: Thanks a lot. Have a great day.

CONAN: And our thanks as well to Bethia Woolf, a food writer here in Columbus. Appreciate your time.

Ms. WOOLF: Welcome.

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