The Sweetest Thing

What is the sweetest thing in the world?

• 0:01Speaker 00

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• 0:38Speaker 01

  Wait, you're listening.

• 0:41Speaker 01

  All right.

• 0:42Speaker 02

  Okay.

• 0:43Speaker 01

  All right.

• 0:45Speaker 02

  You're listening to Radiolab.

• 0:48Speaker 01

  Radiolab.

• 0:48Speaker 02

  From...

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  WNYC.

• 0:51Speaker 02

  See?

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  All right, so Latif.

• 0:56Speaker 03

  Yep.

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  What are we doing today?

• 0:58Speaker 03

  Uh, we're gonna go on a hunt.

• 1:00Speaker 02

  All right.

• 1:01Speaker 03

  That actually starts in my car. I was with my two kids. I think at that point, my kids were six and three, maybe? And the U2 song, "The Sweetest Thing," comes on. Do you know that song?

• 1:16Speaker 02

  Of course.

• 1:21Speaker 02

  Yeah, of course. It's a bop.

• 1:23Speaker 03

  Yeah, it's my favorite of their songs.

• 1:25Speaker 02

  Yeah.

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  And my kids, who have never heard the song before, they're listening to the song, and they ask, "What is the sweetest thing?"

• 1:34Speaker 02

  Did you try love? Were you like, "Love"?

• 1:36Speaker 03

  Yeah, no, my kids, they don't care about that. They were just like, "No, no, but what really is the sweetest thing?"

• 1:40Speaker 02

  So just, what's the sweetest thing I can get in my mouth?

• 1:43Speaker 03

  Yeah, they're kids, they love sugar.

• 1:45Speaker 02

  Yeah, of course.

• 1:46Speaker 03

  Right now, they're obsessed with gummy bears, and they just wanted to know, "Is there some other thing out there we've never had before that's even sweeter?"

• 1:55Speaker 02

  Hmm.

• 1:56Speaker 03

  So I figured, like, I'm a journalist, I can answer this.

• 1:59Speaker 02

  Well, Latif, bless your amazing children who I adore. Do you care about this question?

• 2:06Speaker 03

  Yeah, yes.

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  Why?

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  Because, okay, because it sounds like a dumb, simple question.

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  Or not a dumb question, but it seems like it has an answer, and then you're like, "Son."

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  Yeah, I kind of expected it would be that way, too, but then this question turned out to be so much more.

• 2:24Speaker 03

  More than just a hunt for, like, a substance, it became like this thing where I was trying to get to the edge of human experience. And sweetness as one of those experiences. It's this basic, familiar thing that we all know. It's like almost mundane, but I kept finding that, "Wait a second, like, no, no, no, the edge is even further to these levels of sweetness that I didn't even know existed in the first place."

• 2:53Speaker 03

  And there's some mind hacks and brain lasers and space raspberries. There's a lot of fun stuff along the way.

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  All right, all right, let's go.

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  Okay, all right. So the very first thing that I found, right off the bat, I found all these scientists. Check, check, check.

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  Okay.

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  Hey, okay.

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  Hello.

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  Who are out there trying to answer rigorously scientifically this exact kid question.

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  My name is Eric Walters.

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  Can I call you Eric?

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  Please do, you don't have to doctor me.

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  Like Eric here, a biochemist who used to work at Nutrisweet, where he developed artificial sweeteners.

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  I spent a lot of my career working on sweeteners, studying sweeteners, and ultimately writing a book about sweeteners.

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  And what scientists like Eric in the food industry do is they find, or even make, new sweet molecules.

• 3:43Speaker 04

  Yeah, yeah, tweaking the structure in small ways and seeing, does it get better or worse?

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  And then they literally rank them in terms of sweetness.

• 3:51Speaker 04

  Yeah.

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  And they keep, like, a list of the sweetest things on Earth.

• 3:55Speaker 02

  Oh.

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  And I want to walk you up my top five of the list, using table sugar as our baseline here.

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  Because that's the most common sugar that we use every day.

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  Okay, great.

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  So, number five, honey. You know honey?

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  Heard of it.

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  Honey is about 1.5 times sweeter than sugar.

• 4:15Speaker 02

  Which, what does that mean? It's just, it's just, what does that mean?

• 4:18Speaker 04

  So typically, in the food industry, people do this with trained taste panels.

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  These specialized taste testers who are really good at noticing differences in sweetness.

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  I haven't done it in years, but I used to be very good at it.

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  And here's what they generally do. They take a little sugar.

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  One gram of sugar.

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  Like a pinch.

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  Dissolve it in water.

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  Call it a cup of water. Taste it.

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  Sip and spit.

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  Then they mix the same amount of the thing they're testing, let's say in this case, honey, with the same amount of water. And again.

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  Sip and spit.

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  To see which is sweeter.

• 4:50Speaker 04

  Yeah.

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  Now, to be able to say how much sweeter this thing is than sugar, what you do is you just add water.

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  Until it's the same?

• 4:59Speaker 03

  Until it's the same. So like with honey, you would theoretically need to add 1.5 times as much water for them to taste the same. Then you can say it's 1.5 times as sweet.

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  Yep, there you go.

• 5:14Speaker 02

  Okay, that's a good way to, like, come up with a scale.

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  Yeah.

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  Okay.

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  Okay, so that was honey. Honey was number five on the list. Now, one level sweeter, number four.

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  Aspartame.

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  Aspartame, which is used to sweeten equal.

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  Sure, okay.

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  It's about 200 times as sweet as sugar.

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  So it takes 200 times more water.

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  Wow.

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  With aspartame to taste the same as a cup of sugar water.

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  That's wild.

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  Yeah. Next, number three. This one actually comes from nature.

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  Ooh.

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  Uh, this is a Katemfe fruit, which is a little red berry that grows in West African tropical rainforests.

• 5:53Speaker 02

  Oh.

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  And it is 2,000 times sweeter than sugar.

• 5:57Speaker 02

  Ooh, orders of magnitude.

• 6:00Speaker 03

  Yeah. But then, number two, Adventame. How sweet, just take a guess.

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  5,000.

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  Adventame is 20,000 times sweeter than sugar.

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  Oh my gosh.

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  That means just a pinch of Adventame could sweeten 500 gallons of water. That's like a jacuzzi of sugar water.

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  That's freaky.

• 6:24Speaker 03

  Yeah. Okay, number one. The number one sweetest thing, according to these expert sweetness sippers sitting around in their food labs, is Lugdenum.

• 6:39Speaker 04

  Yeah.

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  I don't even know how to pronounce it, Lugdenum?

• 6:42Speaker 04

  I always say Lugdename, but I...

• 6:44Speaker 03

  Lugdename.

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  Okay.

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  Um, this is 300,000 times sweeter than sugar.

• 6:50Speaker 02

  Oh.

• 6:51Speaker 04

  Yeah, that's what we said.

• 6:53Speaker 03

  Oh my god.

• 6:54Speaker 04

  Yeah, that's, that's insane.

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  Okay, so what is this?

• 6:58Speaker 03

  This is a swimming pool. This is almost a full swimming pool.

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  Wow.

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  What was the mood and the reaction at Nutrisweet to this news?

• 7:07Speaker 04

  I was jealous.

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  Yeah.

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  Wish I'd thought of that.

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  Because in his line of work, they're always trying to push this limit a little bit further.

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  Right.

• 7:15Speaker 04

  I discovered a sweetener that was 28,000 times as sweet as sugar.

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  Interesting.

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  So I didn't win. I didn't win the prize on that one.

• 7:25Speaker 03

  But the prize goes to this, like, Frankenstein of a molecule called Lugdenum. Okay, sit down.

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  The wise man.

• 7:33Speaker 03

  You want a very little amount of this one, okay? You ready? So I set up a little tasting for my kids. Yeah, that's a good amount, huh? Five, too much. I couldn't actually get my hands on any Lugdename, because it turns out it's not FDA-approved for human consumption, because apparently if you try it, there's a chance it turns your blood the color of chocolate.

• 7:59Speaker 02

  What?

• 8:00Speaker 03

  But... Why don't you guys drink some water? I did give them some Adventame, number two on our list. Okay, ready, guys?

• 8:11Speaker 03

  Okay. And...

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  Oh, okay. What do you think?

• 8:20Speaker 05

  Ugly.

• 8:21Speaker 03

  Ugly? You spat it out all over the floor? Okay, Huck is now scraping his tongue with his fingers. What are you doing?

• 8:32Speaker 03

  No, don't, no, no, no, don't spit on the couch. That's gross, man, that's gross. That's gross.

• 8:37Speaker 02

  So the thing that scientists say is 20,000 times sweeter than sugar does not actually taste sweet?

• 8:43Speaker 03

  Yeah.

• 8:43Speaker 02

  Now, isn't that remarkably dumb?

• 8:47Speaker 03

  According to psychologist Linda Bartoszak, this whole ranked list is ridiculous. Like, this is the dumbest way to measure this.

• 8:55Speaker 02

  Huh. Have you ever heard anybody say that saccharin is 100 times as sweet as sugar?

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  Yes.

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  Have you ever tasted saccharin and sugar at the same time?

• 9:04Speaker 03

  No.

• 9:06Speaker 02

  Well, I assure you, you will not think the saccharin is 100 times as sweet as sugar, for god's sake.

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  Well, the, these sweeteners, they do have some off flavors.

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  Eric says that the problem with coming up with a perfect sweetener is that there's only one sweetness receptor. But on the other hand...

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  Humans have, I don't know, 20 or 30 different bitter taste receptors.

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  So it's like a minefield that you have to kind of tiptoe through to get to the promised land of the sweet receptor.

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  Yes, yes.

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  So it's really hard to develop a compound that triggers the sweet receptor, but doesn't trigger any of the bitter receptors as well, which is why you get those off tastes from so many sweeteners.

• 9:49Speaker 02

  Right.

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  But the food chemists, when they're ranking sweeteners, they are just looking at one very specific thing.

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  And that's a value that we refer to as potency.

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  They just want the thing you can use the smallest amount of to turn on that sweetness receptor.

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  The weakest thing you can just taste as sweet. Got it, okay.

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  And that, that kind of measurement is very, very helpful if you are a soda company or making chewing gum or something, and you have a giant vat of something, and...

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  And you want to put in the least amount of a thing to make the most money.

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  Put in the least amount of that thing, right?

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  Right, right.

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  But that's not what my kids are asking. That's not what I'm looking for. We're looking for a whole other thing.

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  And that's intensity of sweetness. How sweet does it actually taste to you? Yeah, I think that's, that's right. Because we're...

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  Talking about sweetness and sweetness as a perception.

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  This is Paul Breslin.

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  Professor in the Department of Nutritional Sciences at Rutgers University.

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  And he says, you know, with things like Adventime, right? You might think that if you just kept adding more and more of it to the water, it would-

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  Keep getting sweeter and sweeter and sweeter until it went to the moon. But it wouldn't. You'll eventually reach a point where the sweetness intensity sort of reaches a plateau.

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  The, the, the amount of sweetness that you perceive sort of levels off.

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  The thing is that our sweetness receptor, it's not just like a regular light switch you turn on or off. It's more like a dimmer switch.

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  Okay, sure.

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  So it can get brighter and brighter. And these sweeteners, they can only get a certain amount of bright.

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  Huh.

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  So what we really want to know is what thing will turn that dimmer switch up the highest?

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  To the brightest bulb?

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  To what'll get you the brightest bulb.

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  Okay.

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  And according to Eric, by that measure-

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  Maybe sugar is the sweetest thing there is.

• 11:44Speaker 03

  No.

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  Because it can get you to a higher perceived intensity of sweetness.

• 11:50Speaker 03

  He's never heard of or tasted anything sweeter than sugar.

• 11:53Speaker 02

  Wait, so is that the answer? The sweetest thing is sugar?

• 11:57Speaker 03

  Which feels like an extremely anticlimactic answer, right?

• 12:00Speaker 02

  That's just why, I mean, we're just back where we started.

• 12:04Speaker 03

  We are, we are back where we started, but like for a kind of profound reason, actually.

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  Sugar plays a critical role in survival. Glucose is the best fuel the brain can use.

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  From the very beginning, Linda says-

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  The first thing when a baby is born, you want the baby to do is nurse. And the baby has reflexes that help it begin to nurse, but the sweet taste of mother's milk-

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  The sugar in the mother's milk.

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  Is what keeps it nursing. So sweet taste is an incredibly important cue.

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  Our brains basically evolved this particular sensation, the reward of sweetness, as a way to get us to want sugar.

• 12:45Speaker 04

  Yeah. The receptors have evolved specifically to respond to sugar.

• 12:50Speaker 03

  Like it's the thing the light switch was made for.

• 12:53Speaker 02

  In fact, there have been theorists in the past who've thought that sweet might be the beginning of our understanding of pleasure. Ooh, that's interesting.

• 13:01Speaker 03

  And so I started to see sugar and sweetness as almost the same thing.

• 13:05Speaker 02

  Right.

• 13:06Speaker 03

  Sweetness doesn't describe sugar. It, it is sugar.

• 13:12Speaker 02

  Yeah.

• 13:15Speaker 03

  Which is cool and which is revelatory of our basic human nature. But also, like, I, I don't know, I still was craving more. Like, there's a limit here. I just want to go beyond it.

• 13:31Speaker 03

  And lucky for me, I ended up stumbling into a whole world of things that could take us beyond that limit.

• 13:41Speaker 02

  Really?

• 13:42Speaker 03

  And I'm going to take you into uncharted sweetness territory. And that's after the break.

• 13:57Speaker 02

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• 16:49Speaker 06

  This is Ira Glass. On This American Life, one thing we like is a good mystery. Sometimes about really big things, things you hear in the news. But most times, the little mysteries are the best.

• 17:01Speaker 03

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• 17:20Speaker 02

  This is Radiolab. I'm Lulu. I'm here with Latif Nasser.

• 17:24Speaker 03

  Yeah.

• 17:25Speaker 02

  Latif is on a quest to discover the sweetest thing in the world, on the planet, the sweetest thing on Earth. And where we left off, you were at a potential answer that the sweetest thing is sugar.

• 17:35Speaker 03

  Yeah, except maybe not. Okay, so Lulu.

• 17:39Speaker 02

  Yeah.

• 17:40Speaker 03

  What is sweeter? A strawberry or a blueberry?

• 17:44Speaker 02

  I think a strawberry.

• 17:46Speaker 03

  So a blueberry has technically more sugar.

• 17:50Speaker 02

  Really? That's right. The blueberry has twice as much sugar in it.

• 17:54Speaker 03

  According to Linda Bartoschek.

• 17:56Speaker 02

  There are fruit that can make their sugar sweeter. What? Now, why do fruits care? Because animals that eat the fruits spread their seeds. So the fruit would really like that sugar to be sweeter. And maybe the fruit doesn't know how to add more sugar to it. I'm, I'm talking about the fruit's got consciousness. Of course it doesn't. Evolution is doing this.

• 18:20Speaker 03

  Right.

• 18:20Speaker 02

  But what has happened through evolution is that some fruit are now using volatiles, which make the smell of the fruit, to increase the sweetness.

• 18:33Speaker 03

  Volatiles are just little molecules that float around in the air. They make things smell.

• 18:37Speaker 02

  Huh. Now, there are two ways you can perceive volatiles. You probably only know about one of them, and that's you sniff them.

• 18:43Speaker 03

  Right.

• 18:44Speaker 02

  But what happens when you put food in your mouth that is giving off odors? You chew it, you're releasing the odors in your mouth. And when you swallow, those odors are pumped through a hole in the back and they go into your nose.

• 18:59Speaker 03

  Uh huh.

• 19:00Speaker 02

  And can intensify the sweet signal in the brain.

• 19:04Speaker 03

  So the strawberry tastes sweeter than the blueberry? Because it puts out all of these non-sugar smell molecules that send smell signals to your brain, which overlap with the taste signals and give them a little boost.

• 19:18Speaker 02

  Huh.

• 19:19Speaker 03

  And according to Paul Breslin-

• 19:20Speaker 06

  As an ape, our species, our natural proclivity is to mostly want to eat fruit.

• 19:27Speaker 03

  Thanks to our long evolutionary history with fruit-

• 19:30Speaker 06

  A lot of animals can make their own vitamin C. Humans can't make their own vitamin C, so we have to eat fruit.

• 19:36Speaker 03

  Even if something just looks kind of fruity or reminds you of a fruit?

• 19:42Speaker 03

  It's like there's an extra little bell ringing in our heads.

• 19:45Speaker 06

  So if you play with vision, if you make something very fruity that you associate with sweetness, you can perceive it as being more sweet.

• 19:53Speaker 03

  Huh.

• 19:53Speaker 06

  Or if you color it red, so it looks like a nice ripe fruit, that can actually make the sweetness perception go up.

• 20:01Speaker 02

  No. So if you were to take the same packet of sugar and dye some of it red, the red would taste sweeter to me?

• 20:08Speaker 03

  That's right.

• 20:09Speaker 02

  That's hard to believe.

• 20:10Speaker 03

  Well, did you bring the stuff I told you to bring?

• 20:13Speaker 02

  Yep.

• 20:13Speaker 03

  Okay, you have some honey?

• 20:15Speaker 02

  I have some honey.

• 20:15Speaker 03

  Okay, well, why don't we first get our sort of baseline? Take a tiny bite.

• 20:20Speaker 02

  Just normal old honey. Here we go.

• 20:22Speaker 03

  Yeah.

• 20:22Speaker 02

  Okay. Very sweet.

• 20:24Speaker 03

  Okay, so number two, I want you to take that honey.

• 20:27Speaker 02

  Okay.

• 20:27Speaker 03

  Grab some strawberry extract and red food coloring.

• 20:30Speaker 02

  Okay.

• 20:31Speaker 03

  Mix that all up.

• 20:33Speaker 02

  Ew, it looks like, um, almost like cherry cough syrup.

• 20:37Speaker 03

  Okay, so to keep that normal honey we just had in mind, now taste the strawberry honey.

• 20:41Speaker 02

  Okay.

• 20:41Speaker 03

  Tell me if it's sweeter.

• 20:43Speaker 02

  And I should like look, I guess.

• 20:47Speaker 02

  Oh.

• 20:49Speaker 02

  Significantly. Significantly. Yeah, wow.

• 20:53Speaker 03

  It's kind of dramatic, right?

• 20:54Speaker 02

  Yeah. It's interesting. It's not sweeter in like what I was expecting, like a syrupy sweeter way. It's-

• 21:00Speaker 03

  Yeah.

• 21:01Speaker 02

  It's almost like I picture all these like flowers, like it's like flowery sweeter.

• 21:06Speaker 03

  Okay, now-

• 21:07Speaker 02

  There's another thing?

• 21:08Speaker 03

  Yeah. I mean, by this point, I was obsessed with ways to jack up the perception of sweetness. And I found all these studies that suggest that along with smell and vision, sound actually works for sweet as well.

• 21:20Speaker 02

  What?

• 21:20Speaker 03

  So there are certain high-pitched tones that you can play and you can enhance sweetness by as much as 5 to 10%.

• 21:29Speaker 02

  Wait, why would that be? What's the evolutionary, what's the why?

• 21:35Speaker 03

  Such a good question. I looked it up and no one knows for sure.

• 21:40Speaker 02

  Okay, fair.

• 21:41Speaker 03

  Uh, it is a mystery.

• 21:42Speaker 02

  Okay.

• 21:42Speaker 03

  But they have seen it happen over and over in experiments. Okay, so like I'm about to play you a song. This was used in a study at the Science Museum of London.

• 21:53Speaker 03

  Here, let's, let's just see if it works for you.

• 21:54Speaker 02

  Okay.

• 21:55Speaker 03

  Okay, you ready?

• 21:56Speaker 02

  I'm ready.

• 21:56Speaker 03

  Okay, here it is.

• 22:02Speaker 02

  This is like the music you see in like 1950s animations of candy dancing.

• 22:07Speaker 03

  Okay, eat the red honey again.

• 22:09Speaker 02

  Okay.

• 22:12Speaker 02

  Wow, it gives it like more dimension.

• 22:18Speaker 02

  It's sparklier, crystallier.

• 22:23Speaker 03

  Uh, when you talk about the crystals, is it because your honey is like kind of hard?

• 22:27Speaker 02

  My honey's a little old.

• 22:30Speaker 03

  So maybe the crystalline quality is because of the old honey, really, instead of the music?

• 22:35Speaker 02

  Uh huh.

• 22:35Speaker 03

  Okay, but I do, I do agree. I think there was a step up.

• 22:38Speaker 02

  The, the strawberry step up was pretty dramatic.

• 22:40Speaker 03

  And I feel like the sound step was maybe harder to tell.

• 22:43Speaker 02

  Yeah, a little subtler.

• 22:46Speaker 03

  So at this point, I was like, okay, cool. These hacks definitely work. But also they're not so dissimilar, like the flavor and the color. It's not so dissimilar to what candy companies are already doing. Like, it just felt like I was like, oh, I feel like I'm back to gummy bears here.

• 23:01Speaker 02

  Right.

• 23:02Speaker 03

  And then I was like, how could we get even sweeter than this?

• 23:04Speaker 02

  Uh huh.

• 23:05Speaker 03

  So then I thought, what if we just went to the source of all of this?

• 23:08Speaker 01

  Remember, you know, taste ultimately is in your brain.

• 23:13Speaker 03

  Which took me to the lab.

• 23:14Speaker 01

  Okay, here we are. We're at Columbia University with all these like brain scans on the wall here.

• 23:19Speaker 03

  Of this geneticist and neurobiologist.

• 23:21Speaker 01

  Nice to meet you.

• 23:22Speaker 03

  Dr. Charles Zucker.

• 23:24Speaker 01

  I'll shake the microphone.

• 23:25Speaker 03

  He was one of the people, uh, along with other scientists like Danielle Reed, who discovered the sweetness receptor.

• 23:32Speaker 02

  Oh.

• 23:33Speaker 01

  And I've dedicated my career to study how detection gets transformed into perception.

• 23:41Speaker 03

  And since then, he's been following that sweet signal from the taste receptor into the brain.

• 23:48Speaker 01

  So it goes from the tongue to ganglia, from ganglia to brain stem, brain stem to a different station in the, in the brain stem where it gets further processed. From there, then it goes to the thalamus, and the thalamus goes to the cortex.

• 24:03Speaker 03

  Somewhere along the way here, we know that sight and smell can join up and boost the signal. But regardless, the cortex.

• 24:09Speaker 01

  Is where you now say, ah, this is sweet.

• 24:14Speaker 02

  Huh.

• 24:15Speaker 01

  I was saying, you know, the typical laboratory, you know, you have benches and you have desks.

• 24:19Speaker 03

  So we actually visited Charles's lab.

• 24:21Speaker 01

  And then we have lots of specialty rooms.

• 24:23Speaker 03

  Where he studies this pathway to see, okay, what happens if we move this over here? Or what if, what happens if we change, what happens if we block it over here?

• 24:33Speaker 02

  Or if we block the train here or something?

• 24:34Speaker 01

  So normally the cells have the sweet receptor, and that's why it's sweet activates that pathway all the way to the brain.

• 24:39Speaker 03

  Yeah.

• 24:40Speaker 01

  But if instead there I put, let's say, a bitter receptor, now the bitter chemical will activate the same sweet pathway. Right.

• 24:48Speaker 02

  Whoa.

• 24:49Speaker 03

  To be clear, he is not doing all of this for the reasons that we are to try to find the sweetest thing or the sweetest sensation. He is working to understand really how sweetness and taste work in the brain. And who knows, maybe that knowledge could help us deal with issues like addiction, obesity, eating disorders, diabetes.

• 25:12Speaker 02

  Yeah, sure.

• 25:13Speaker 03

  So one of the things he's doing is he takes some mice and he zeroes in on their sweet taste sensation neurons.

• 25:21Speaker 01

  We introduce into only those neurons, a little light switch.

• 25:25Speaker 03

  Meaning they genetically engineer these neurons and add a genetic sensitivity to light.

• 25:32Speaker 01

  And then we put a fiber optic in their head.

• 25:34Speaker 03

  Ah.

• 25:36Speaker 01

  And then we turn the laser on.

• 25:37Speaker 03

  Which triggers the neuron.

• 25:39Speaker 01

  And the brain will say, ah, sweet.

• 25:42Speaker 02

  Oh my gosh, oh my gosh.

• 25:44Speaker 03

  Um.

• 25:45Speaker 02

  So, and they be, by, by beaming in light, it just, whatever it's tasting will taste sweet?

• 25:50Speaker 03

  Yeah, even if it's not tasting anything.

• 25:52Speaker 02

  What?

• 25:53Speaker 03

  We, I mean, why are we then even bothering with candy instead? Why don't we just do that to ourselves?

• 25:58Speaker 01

  Very good. Excellent. Come on, people go around with pacemakers.

• 26:02Speaker 03

  Yeah, sure.

• 26:03Speaker 01

  And, and I could see a future that could be done.

• 26:08Speaker 03

  Which, I mean, in terms of lifestyle, like that, that could be, just imagine, like, that could be revolutionary. Think about like, you could get the perfect sugar hit, no calories, no insulin spike. You could even pair it with whatever you want, which means like your kids could be eating spinach and it tastes like candy, right?

• 26:27Speaker 02

  Yeah, okay, that's, that's kind of neat.

• 26:30Speaker 03

  Yeah, but because we're on this mission here for the sweetest thing, I was like, wait a second. But could you use that same thing? Could you use that same laser light and crank it up to the highest it can go? And just blast that sweet neuron and get something that is the sweetest thing that anyone has ever tasted?

• 26:54Speaker 03

  Like, you could maybe get a sweetness that we have never known.

• 27:01Speaker 03

  A sweetness that has just been totally blocked off from us, just from the physical reality of sugar. So I asked him and Charles was like.

• 27:13Speaker 01

  In principle, I could imagine, yes.

• 27:15Speaker 03

  You could potentially create the sweetest sweet. You could transcend. The sweetest thing could be light, like could be nothing.

• 27:32Speaker 02

  I don't like it.

• 27:35Speaker 03

  You don't like it?

• 27:35Speaker 02

  I don't like it.

• 27:36Speaker 03

  Why not?

• 27:37Speaker 02

  I don't know. It's like, let's divorce ourselves from the real world even more so that pleasure itself doesn't even have to be found. Your, your boys asked this question about what is there to find in the world? This just says, you can get it from the inside and aren't we siloed enough?

• 27:54Speaker 03

  Yeah, I mean, kind of, but like, really, it's, I feel like the, my takeaway from all this reporting is like, it's kind of all happening in your mind anyway. It's all a mind game.

• 28:06Speaker 02

  Hmm.

• 28:07Speaker 03

  Taste. And for me, like talking to Charles, I was just like, whoa. We're opening up a whole new world. Like, what even is possible here? Like, what could we do? What, what are the, what are the places we could go?

• 28:21Speaker 02

  Yeah, but it's, it's like, uh, the whole new world is just on your couch. Like, at least with a search, you have to get out the door and be surprised. Like, if somebody uses this, what, what incentive do they have to leave, to leave the house?

• 28:38Speaker 03

  Yeah, I mean, sure, but like, but if you could definitively know that this experience will be sweeter than anything you could ever experience out in the world, wouldn't you try that?

• 28:52Speaker 02

  Maybe.

• 28:53Speaker 03

  Okay, okay.

• 28:54Speaker 02

  I'm just not sure I'd like.

• 28:55Speaker 03

  Okay, I get your, I get your hankering for wanting to go someplace new. Let me take you one last place that this mapping of sweetness took me, um, that I, I did not expect.

• 29:08Speaker 02

  Okay.

• 29:09Speaker 03

  So last month, a team of researchers at the Center for Astrobiology in Spain

• 29:17Speaker 02

  Mm hmm.

• 29:18Speaker 03

  were looking at a cloud of interstellar dust and gas near the center of the Milky Way. You know, spectroscopy, you know about that?

• 29:26Speaker 02

  I think it's like you detect based on the light waves being emitted, you get clues on what the substance is.

• 29:32Speaker 03

  That's right.

• 29:33Speaker 02

  So cool.

• 29:33Speaker 03

  So they, they did this on this kind of cloud of interstellar dust. And what they found in that cloud was a huge amount of a molecule called erythrolose.

• 29:47Speaker 02

  Erythrolose, okay.

• 29:49Speaker 03

  It's a four-carbon sugar. This is the first time ever they found a, not only a sugar, a relatively complex sugar in deep space.

• 30:00Speaker 02

  What, and would it taste like sugar to us?

• 30:05Speaker 03

  So the crazy thing.

• 30:07Speaker 02

  Yes.

• 30:08Speaker 03

  Is that this exact sugar, erythrolose.

• 30:12Speaker 02

  Yes.

• 30:13Speaker 03

  Happens to be found.

• 30:14Speaker 02

  Yes.

• 30:15Speaker 03

  In raspberries.

• 30:17Speaker 02

  Oh.

• 30:18Speaker 03

  Yeah.

• 30:18Speaker 02

  Wait, wait, space tastes like raspberries?

• 30:20Speaker 03

  No, no, no, just this one cloud. But it does, it does make you wonder, right? Like, if this is just out there as a raw material, just floating, like, maybe that is a big clue for us that there is a space raspberry somewhere.

• 30:38Speaker 02

  Whoa. And, and, and do they now think maybe there's sugar like all up in Neptune and, and burning out of the sun?

• 30:47Speaker 03

  There has to be enough of it that you can read it on a mass spec.

• 30:52Speaker 02

  The scientists have spectroscopy. They need taste oscopy.

• 30:55Speaker 03

  Hubble telescope. It's just like a giant tongue that they send out.

• 30:59Speaker 02

  You know, you just make a rocket with just the tongues. You're just eh.

• 31:02Speaker 03

  The James Webb Tongue, yeah.

• 31:04Speaker 02

  The James Webb Tongue, yeah. And then, you know, you add in microgravity. Is that going to work like sonic seasoning to even amp the sweetness some more?

• 31:13Speaker 03

  Yeah, like what color? Oh, God.

• 31:31Speaker 02

  Latif Nasser, who himself scores pretty high on my list of the sweetest things on this planet.

• 31:37Speaker 03

  If only my kids liked me as much as they like gummy bears. Uh, thank you to you, Lulu. Thanks to my kids. Thank you to Jialin Deng, who composed the song that was our sonic seasoning. Thank you to Laura Rickman and everyone else at Columbia University's Mortimer B. Zuckerman Mind-Brain-Behavior Institute for hosting us. And a major thank you to Grant Dubois, to Charles Spence at Oxford University, and to Danielle Reed at the Monell Chemical Census Center. They were all extremely helpful in explaining their work and taste in general to us. Uh, we're very grateful for their help.

• 32:15Speaker 02

  This episode was reported by Latif Nasser with help from Jessica Young.

• 32:19Speaker 03

  It was produced by Jessica Young with help from Mona McGaucker, Maria Paz Gutierrez, Gabby Santas, and Maya Appleby Melamed.

• 32:27Speaker 02

  It was edited by Pat Walters, fact checking by Sophie Sami E. This is Radiolab. I'm Lulu Miller.

• 32:32Speaker 03

  And I'm Latif Nasser. Say sweet, everybody.

• 32:36Speaker 02

  Bye.

• 32:41Speaker 02

  Uh, this is Lulu here from a couple of weeks after we recorded this episode with a note that I'm passing along from Latif. Uh, he's not reading it himself. You'll see why. Here we go. Okay, so, hey folks, Latif here. Before we leave you, I just wanted to let you know, possibly TMI, that I injured my vocal cords. It's nature's way of telling me I talk too much. And I'm under a doctor's orders to talk as little as possible for the next couple of months. So I'm off on medical leave, putting a sock in it, so to speak. I'll be leaving you and your ears and brains in the capable hands of the rest of the Radiolab team. We have fascinating episodes coming up from Matt and Molly and Annie and Avir, and of course, Lulu. Yeah, thanks, uh, about everything from grass to sulfur to, well, death. I'll be back before you know it. Take care of your throats.

• 33:27Speaker 02

  Uh, Latif, take care of your throat. Tea, rest, no talking. Uh, we love you, Latif. And again, don't worry, friends, we have so many goodies coming up, uh, some of which Latif was already in, so you'll probably be hearing him anyway. And he will be back in a couple of months. Thanks for listening.

• 33:44Speaker 07

  Hi, I'm Eva and I'm from Brooklyn, New York. And here are the staff credits. Radiolab is hosted by Lulu Miller and Latif Nasser. Soren Wheeler is our executive editor. Sarah Sandback is our executive director. Our managing editor is Pat Walters. Dylan Keefe is our director of sound design. Our staff includes Jeremy Bloom, W. Harry Fortuna, David Gabel, Maria Paz Gutierrez, Sindhu Nainas Ambundam, Matt Kielty, Mona McGaucker, Annie McEwen, Alex Neeson, Sarah Kari, Natalia Ramirez, Joanna Strogatz, Anisa Vitsa, Ariane Whack, Molly Webster, and Jessica Young.

• 34:28Speaker 07

  With help from Gabby Santas and Maya Appleby Melamed, our fact checkers are Nora Belbidea, Hillary Elkins, Rachel Gross, Diane Kelly, Emily Krieger, Natalie Middleton, and Sophie Sami E.

• 34:44Speaker 05

  Leadership support for Radiolab's science programming is provided by the Simons Foundation and the John Templeton Foundation. Foundational support for Radiolab was provided by the Alfred P. Sloan Foundation.