(lively rhythmic music) (chips crunching noisily) - You're hearing the crunch as I eat these delicious chips, but here's what I'm hearing through my headphones when I take a bite.

(chips crunching squishily and gloopily) This is the grossest experience of my life!

(chips crunching squishily and gloopily) Aw!

That was the worst chip I've ever eaten.

Nothing was wrong with it except that I heard it make a gross sound, and that totally messed up its flavor, but how can a sense like hearing mess with how we perceive flavor?

Maybe you and I have been thinking about flavor all wrong, because it turns out it's way more complex than just how something tastes and smells.

So what does flavor really mean?

How many senses does it actually involve?

And why is it so tied to things like memories from childhood?

Today, we're visiting a flavor manufacturer to meet one of the world's top flavorists, and I'm gonna fool my brain into smelling and tasting things that aren't even there.

This is the science of flavor.

(lively rhythmic music) We're at a flavor laboratory in Austin, Texas, to ask, what is flavor, anyway?

I mean, there's smell, there's taste, like, there's crunchiness, it's, like, the feel of things, and, like, your memory, and like, I don't know.

So this is like the pro sports of flavor, right here?

- Yes.

- You're, like, in the NFL?

- There's less of us than pilots.

Let's test you and see how good your nose is.

- Okay.

- We're gonna test some raw materials, and they're for our characterizers for our flavors.

We have different notes that happen within a flavor, but these are the ones that are really going to drive it home what it is.

- So this is like the core fingerprints of the flavor, - This is like - the identity of the flavor.

- Th quintessential.

- Okay.

- First one.

(light rhythmic music) - Wait.

Oh, this one I know.

- Okay.

- This tastes like, like, baking almond extract.

- This is actually kind of a trick, - Okay.

- because it can be used in almonds and cherries.

It's very, yeah, - as soon as she said that, - I saw that mindset, - it's like maraschino cherries.

- It has, like, that artificial cherry note.

- Those red cherries that go on top of ice cream, like (indistinct).

- Yeah, the maraschino cherries.

- That's amazing.

How many people on earth have your flavor certification?

- I am certified through the Society of Flavor Chemists.

There's about 500 of us.

You have to not only gain employment with a flavor house, but they have to have a certified flavorist who agrees to train you.

- You're just like studying flavors - All the time, - all the time, - for seven years.

- just smelling everything you can get your hands on?

- Yes.

- So you're now like a walking, talking encyclopedia of flavor.

- I hope so.

Okay, you ready?

- I think so, famous last words, okay.

This is very banana-y.

I'm getting a lot of, this is a tropical, but I feel like there's a trick.

It can't just be banana, right?

- It is banana.

- It is just banana?

- It is just banana, - Okay.

- and it's interesting that you said tropical, because it can go in tropical stuff, too, it's not just bananas.

- Even if it's not literally banana-flavored, - It can be a secondary player - you would put that in there.

- for something else, and maybe not the primary, and so it's just different amounts of paint that you're using for your picture.

- Okay, we're moving to savory.

(oil sizzling) This is a funky one.

Cooked vegetables, like, soup base, like, carrots, and celery, and stuff.

- But kind of porky.

- I get the pork in there, now that you say it.

- It's a Tonkotsu ramen.

- How do you make something porky?

Like, what does porky even mean, chemically?

- There's more paints, and that's what this particular flavorist did, was build that realism that goes with it to give you that illusion that you're having Tonkotsu ramen.

- It's garlic, onion.

It's like french onion soup?

It's a brown note.

- You're learning.

- If this doesn't work out, you know... (Lauren laughs) - And last one.

- Ooh, roast beef.

- It is beef.

- After experiencing some truly mind-blowing flavors in the lab, I have to ask Lauren, what is a flavor, anyway?

- Basically, a flavor is aroma materials in a solvent that imparts aroma and taste with no nutritional value, - But a lot of emotional value.

- There you go.

- When we taste something, we're experiencing the molecules it's made of, those aroma materials.

If the innate properties of molecules were all there was to a flavor, Lauren's job would be way easier, but these molecules have to be perceived by our weird, messy bodies, and that makes things way more complicated.

You might not expect it, but eating these chips is gonna activate nearly every sensory system in my body.

Let's start with taste perception, also known as gustation.

(Joe crunching noisily) The little bumps on our tongue, called papillae, each contain a bunch of taste buds.

Each taste bud is home to a cluster of receptor cells, and each receptor cell responds to a different taste.

We have receptors for sweet, salty, sour, bitter, umami, and possibly even fat, as well.

All these receptor types are found in taste buds all over the tongue.

They are not arranged in distinct little regions like that ubiquitous tongue taste map suggests.

I repeat, this map is a myth, (alarm beeping) It has been debunked.

Experts are literally begging us to stop talking about the tongue taste map.

- Please stop talking about the tongue taste map.

- As I eat this chip, I'm tasting some saltiness, savoriness, a little acidity.

Each of those receptors in my tongue is getting triggered by a different chemical component in my food.

The salt receptors are responding to dissolved sodium ions, the umami receptors to an amino acid called L-glutamate, and the sour receptors to dissolved hydrogen ions, basically, the pH of the chip.

But just how good am I at tasting stuff like chips?

Well, there's actually a test for that.

- This is our next test to see if Joe's a super taster, - I really wanna be a super taster.

- You've been itching to know your whole life if you're a super taster, - Yeah.

- and now is the moment.

- I'm not gonna be disappointed if I'm not, okay?

The paper strip contains a bitter-tasting chemical, but different people have more or fewer receptors in their tongue for that bitter chemical.

The strength of my reaction will tell me if I'm a non-taster with no receptors for that chemical, an average taster, or a super taster.

Okay, here goes.

- Ready?

- Uh-huh (indistinct) - Is it super offensive?

- It's not good.

This is a great way to talk.

- I would say you're a moderate taster.

You can detect that it's there, but you're not pulling it off of your tongue.

- If you were a super taster, it'd be like overpowering?

- So, whenever I think about tasting this, I get goosebumps because I hate it so much.

(Joe laughs) The fact that you can put it back on your tongue is alarming, - Okay, So I'm not a super taster, but I'm- - I don't think you're a super taster, but you can taste well.

- Okay, but I'm not a non-taster.

- You're not a non-taster.

- Super tasters tongues also have denser taste receptors than non-tasters.

In fact, individual variation in receptor density is way higher for taste than for any other sense.

These little bumps on our tongue have the power to make us experience the exact same food completely differently from another person.

Whoa, does that mean that, like, my nacho cheese chip is different from your nacho cheese chip?

Now let's move on to smell perception, also known as olfaction.

Now, who do you think would win in a flavor fight, olfaction or gustation?

Well, let's do a little experiment.

I'm gonna try to tell the difference between foods with similar textures while blindfolded and holding my nose.

My olfaction will be completely cut off, but my gustation will work just fine.

- Which one should I go for first?

This one?

I think I'm gonna do this one first.

(Joe crunching) It's crunchy.

Literally, just crunch.

I have no taste.

Okay.

All I have is sweet.

There's nothing else happening.

Is this the third one?

- Mm-hmm.

(Joe chewing loudly) - This is also just crunchy and sweet.

Those are different 'cause they're just sweet and crunchy.

- I don't know what this was.

This had no, this had no flavor at all (blows a raspberry).

These two, they're just sweet.

I think this is apple and this is pear.

I'm gonna reveal.

What?

This was apple and this was pear?

I would totally have guessed otherwise.

I was wrong, so that test shows us olfaction is the real hero of flavor perception, it's the dominant sense over gustation.

So there are actually two types of olfaction.

If I sniff this chip (Joe sniffing) and perceive that distinct cheesiness, that's orthonasal olfaction, the scent particles are traveling up my nose, but if I eat this chip and perceive its cheesiness, that's retronasal olfaction, the scent particles are traveling up the back of my throat into my nose.

Now, retronasal olfaction is what's responsible for most of flavor perception.

The destination of those scent particles is the olfactory epithelium, a patch of millions of olfactory receptor neurons embedded in your nasal cavity, and one end of those receptors is exposed to air.

No other neurons in our body do this.

A scent molecule needs to be the right shape to fit its corresponding receptor, but that means we need so many different receptor types to smell all the smells out there.

We actually have more genes for olfactory receptors than any other type of gene in our genome.

We have about 350 receptor types that work in combination to allow us to detect roughly 10,000 or so smells, but about half of our olfactory receptor genes are no longer functional, meaning that our ancestors could likely discern a much broader bouquet of scents.

Kinda makes you wonder, what would Homo heidelbergensis have thought about these?

Probably would've loved them.

Once our olfactory receptor neurons fire, they send signals to the olfactory bulb of the brain, which is right about here-ish, which then transmits them directly to the olfactory cortex for processing, which is right about... You know what, bring up the diagram.

After the olfactory cortex, smell information goes to the amygdala, a key brain region for processing emotions, and the hippocampus, which is critical for processing memories.

This is a super different signaling pathway than any of our other senses.

Taste, vision, hearing, and touch signals, they all take completely different paths before heading to memory processing.

Because flavor signals pass through those emotion and memory centers of our brain is precisely why flavor evokes such strong emotions and memories compared to other senses.

Taste and smell are crucial to flavor, obviously, but we can't ignore hearing, which, until recently, was the forgotten sense in flavor research.

These days, flavor scientists have come up with an equation for the perfect bacon crunch in a BLT.

They've defined the ideal frequency ranges for crispy and crunchy food noises.

It's these, by the way.

Scientists have even studied how sounds impact our overall perception of flavor, like what happens if you hear a squish, oh, while you're expecting a crunch, but hearing's influence on flavor can be even more subtle than that.

In one study, participants rated chips as being more stale if a lower-frequency crunch was played in their headphones while they ate it.

There are other flavor senses, too.

There's also somatosensory perception, which gives us a lot of information about what we're putting in our mouths.

We're talking touch receptors that detect texture, mouth feel, even fizziness, thermoreceptors that let us know how hot or cold something is, and pain receptors that can tell you how spicy a chip is.

The somatosensory system interacts with our other senses to impact how we perceive flavor.

Sweet things feel more viscous.

Warm food tastes more flavorful.

Spiciness decreases our sensitivity to other flavors.

Finally, we also have to talk about vision.

It impacts our anticipation of food, and this is important, because that triggers our autonomic nervous system, which turns on our salivary glands to get ready to eat, but it also impacts our perception of flavor, and scientists are having way too much fun figuring that out.

They have served wrong-colored foods at dinner parties and then watched all the guests all start to feel ill even though the food was totally fine.

They tricked sommeliers into thinking white wines are reds just by adding food coloring, and they messed with the lighting to turn food weird colors.

- Oops, sorry.

- And beyond our senses, I mean, things like language and culture can even influence flavor.

If you tell someone a certain smell is coming from cheese, - Mm!

- they'll have a different reaction to it than if you say that smell is coming from sweaty feet, - Ugh!

- even when it's the same smell molecules coming from each.

Studies of cultural impact on flavor perception are fascinating.

In one example, American study participants experienced heightened almond olfaction when holding a sugar solution in their mouth, while Japanese participants experienced heightened almond olfaction when holding an umami MSG solution in their mouth.

Researchers think it's because we have different cultural associations about whether something like almond should be sweet or savory.

So, yeah, master flavorists have their work cut out for them.

They have to juggle our senses, our very unpredictable interactions, and their cultural and linguistic contexts, all to create a delicious perception in our brain.

Let's see how this all comes together in the lab.

When you're actually making a flavor, what does it mean to make a well-balanced flavor that's a good experience for somebody?

- A well-balanced flavor has to have a front, a middle, and an end.

It's a story that has a great beginning, gets your attention, has really great middle notes, and finishes off with, like, a bang, basically, and that's what we're gonna do here.

- So these are, like, the individual components?

- Yes, and then at the end of this, you can tell me what you think the flavor we built is.

Okay, so this is the first one.

This is an ester.

- Yeah, it's like a sharp, like, it's a chemical fruitiness.

- Different chemical classes have different waves, different makeups that allow it to come across in different times, so an ester is gonna come in the beginning.

This is a lactone, so this is heavier.

- It is earthier.

Yeah, it's like, lower.

It's like a base note.

- A lactone usually is creamy, fruity.

- Creamy, I get that, yeah.

And then those two together, that's, yeah, you can tell, like one, yeah, it's hitting in different parts of my skull.

This is fun.

(Lauren laughs) Okay, hit me with the next one.

- This is an alcohol, so this is gonna be one of our front guys as well.

- Oh, yeah, very alcoholic.

Whoo, it's not quite what mowing the lawn smells like, but it's definitely that, like, wet, like, crushed up, like leaves, grassy kind of thing.

- So the green will add some unripened notes.

- Unripened, I like that.

- Yeah.

I'm glad you're here to give the good words.

- No, you're doing a really great job.

Okay, so this one is a ketone, - Ooh, I'm getting candy.

- and it gives like a perception - As a cooked sugar - of cooked.

- Yeah.

- Yes, perfect.

Obviously, we're making a fruit, right?

- Mm-hmm.

- It's telling you, okay, you have those unripe notes because fruits can be unripe, and you have a little bit of those cooked notes because as they age, they do create sugars.

- The weirdest game of cards I've ever played, right here.

- [Lauren] So this is another ketone.

This is actually one of my favorites.

- This one's very sharp, like, pointy.

- [Lauren] It's seedy.

- It's like those strawberries you get in the pack that are not quite ready to eat.

- Yes, so put that with your group and smell that.

Isn't it crazy how it's getting - Whoa!

- more and more complex as it's going?

- Yes!

- And we're not even done yet.

- You can feel them, like... - But they're all working together.

They're basically singing "Kumbaya" right now.

- Yeah, they are.

We have a great choir coming in.

Okay.

- Okay, so sniff lightly, this is an acid, - Okay.

- so it's another one of our front guys.

- Okay, yeah, that's a little, that's a little funky, very sharp, cheesy, like there's some aging going on here.

Like if I was in Fruitville, I'd be like, this is not, that one's going back.

- [Lauren] On its own, yeah.

- I mean, it's weird.

Once you put it with the other ones, yeah, it like fills out this flavor.

- And it brightens it, it lifts it.

- And now that strawberry just became, like, somehow riper, - Yes.

- Like, fuller, in this.

- More realistic.

- What the heck is going on?

Brains are weird.

- Okay.

- Okay, last one.

- This is a sulfur.

- Okay.

- What does it smell like?

- Rotting is what it smells like.

It just smells like... - It smells like canned corn.

- Oh, my god, it does.

(both laugh) Gonna get these all together.

(lively rhythmic music) Hah, this is wild.

I'm holding a strawberry, like, every piece of the strawberry.

You don't wanna get any one of them too strong.

There's, like, ripeness, and like, almost like fermented, like vinegary notes in there.

It's like the whole life of a fruit going on here.

- And the leafy green, - Yeah.

- the juiciness of it.

- All right, new YouTube feature needed, Smellavision.

This is like, - It's witchcraft.

- You're like Willy Wonka.

- Oh, thank you.

- Yeah, this is amazing.

This has just been such a mind-blowing experience.

You can tell my brain's kinda melting.

- You're in the matrix right now (laughs).

You are tasting these flavors.

Even if it's not that actual strawberry, it is the flavor of a strawberry, and the way that your mind connects it to make it real to you.

It's important to know that it is a valid thing to be tasting, and even though it is concocted by, you know, a flavorist, and everything, it is what a strawberry would be in nature, just not from the direct strawberry.

- The brain doesn't lie, people.

If it thinks strawberry, then it's strawberry.

- There you go.

Not only are you creating a flavor that tastes good, but you're also evoking a memory for somebody.

- 'Cause there's so many other things that go into that experience, right?

We've all had, like, a meal that just tastes so perfect because of, like, the people you're with, - Yes.

- or where you are.

- It could have been your grandmother's last time to create a lasagna for you, or ice cream cone that, you know, you and your best friend had whenever you were five.

People are tasting it, they're seeing it, they can pick up, like, those notes that we talked about, but then it triggers something and it makes it even more special to them that they're having that with the flavor itself.

If I can bottle one feeling, probably just happiness, because the flavor should make you feel happy whenever you're enjoying it.

We try to make the world taste better.

- I thought consulting a flavorist might reveal some singular truth about the definition of flavor, but instead, I'm kinda wondering whether flavor's even real.

I mean, even experts don't agree on exactly what it is, but it's as clear as the crunchiness of a delicious chip that the way we perceive flavor is a symphony of many senses, way beyond just taste and smell, carefully orchestrated by our brain and even etched into our memories.

It's a deliciously complicated lens through which we experience the world.

And now I can eat chips again without it being a science experiment.

Stay curious.

(Joe crunching loudly) - Need more shoots with food.

Mm, good.

It's snack time Hey, welcome to Joe reviews chips.

- [Background Voice] Keep the code runner still.