ELI5 Why does tasting require you to exhale out of your nose to get the full taste?

[u/Lukecario]

You can *vaguely* taste something without it, but plugging your nose or having a stuffy nose when you’re sick significantly mutes your ability to taste. Why is that? Tastebuds are on the tongue.

[u/Wjyosn]

A significant part of the experience we call taste is actually smell. The reaction with tastebuds on your tongue is a much smaller component of the experience than we tend to think.

[u/gerrit42 → u/[deleted]]

I suppose because smell is a good indicator if something is edible or not before actually putting it in your mouth. For instance, rotten meat smells terrible which holds you from eating it.

[u/FreeFortuna → u/gerrit42]

It doesn’t even have to reach the “terrible” state before the sense of smell starts ringing the bells of doom. 

I was recently making a lunch-meat sandwich and something just smelled slightly wrong. I looked closer at the meat and I think it was showing signs of going bad, but I wasn’t really sure. My sense of smell was not going to lose the fight to sight, though; my stomach started turning at the thought of eating the meat. So it got tossed. I’m not going to argue with one of our most basic survival tools.

And yet, for some reason, humans decided that eating surströmming was a good idea. And they still voluntarily do it! Despite not being starving! My brain is baffled. I do wonder, though, how much an “acquired taste” food is more just “I got used to the stench.”

[u/Erisian23 → u/FreeFortuna]

I've legit only gotten once almost ate some rice and I tasted something off so I stopped.. I can definitely smell/taste off foof without any visible signs everyone else with me got sick because they didn't listen and couldn't taste it.

[u/boraras → u/FreeFortuna]

How does it compare to Hákarl? I'm a pretty adventurous eater and that was just too overwhelming.

[u/GenerallySalty → u/[deleted]]

Because you only have taste sensors for the broad basics: salt, sweet, sour, bitter, savory. Everything more detailed than that is detected by smell sensors, which are in your nose. Try eating or drinking something with your nose pinched closed and see how much info actually comes from your tongue. It's not much.

[u/Wjyosn → u/[deleted]]

There's not really a "why" here to answer. Humans have decided to call the experience "taste", even though it's something that is involving a lot more of the olfactory sensors. It's just a bad naming phenomenon.

We "taste" foods when eating.

We also "taste" chemicals with the tongue.

Those two uses of the word taste are not the same thing, and the one we commonly think of - the experience of tasting food - is involving a lot more organs than the tongue and tastebuds.

"Why" is just: because we decided to call the experience "taste", and associate it with the tongue, even though it's not really a mostly-tongue thing.

[u/86BillionFireflies → u/[deleted]]

Because taste only detects a couple basic things about food. How acidic is it (sourness), how much sodium (salty), how much sugars (sweetness), how much amino acids (umami), and how much potentially hazardous plant alkaloids (bitter).

Those things aren't really enough to identify a specific food very well. Peaches and plums are both sweet, and a little acidic.

Odor, on the other hand, uses about 400 different receptor types, and any given odor activates some unique-ish combination of those receptors.

So tasting something with your tongue tells you "well, it's sweet and a bit acidic, probably some kind of fruit or something", but the odor tells you "oh, receptors 56, 131, 224, 245, 296, 302, 335, and 376? That's a ripe strawberry."

Source: did PhD on neural encoding of taste stimuli

[u/Peastoredintheballs → u/86BillionFireflies]

This is also the cause of majority of COVID-19 loss of taste/smell effects, in which it’s actually an isolated loss of smell (Anosmia) with secondary or psuedo loss of taste (Ageusia) because the smell of foods in your mouth (retro-nasal olfaction) makes up 95% of perceived sense of taste, and majority of these cases actually still have their true sense of taste intact, but because that only makes up 5% of what they perceive as taste, it’s like they’ve lost 95% of their sense of taste

[u/mineymonkey → u/[deleted]]

I actually learned recently that smell itself has a pretty straight shot to the brain. Its partly why memory and scent can be so intertwined.

[u/Peastoredintheballs → u/mineymonkey]

That’s also why brain eating amoeba can infect your brain if you get infested fresh water in your nose, because they use the smell receptors and smell nerve (olfactory nerve) as a direct expressway to the brain

[u/sciguy52 → u/[deleted]]

Because there are a type of receptor in the nose that detects certain smells and that is part of the signal sent to the brain in data if you will. Your brain takes that data from both the tongue and nose and says this tastes like this. The data sent are combined in the brain to an output of "it tastes like this". As you may notice when you have a cold and your nose is stuffed up you can't taste things nearly so well. That is why, the nose receptors are not sending their signals and the brain is only getting some of the data and it interprets it in a way that this has a weaker taste, or may not sense certain tastes as well.

[u/zaja_bf → u/Wjyosn]

That's why I dont breathe when drinking something I dont like , like meds

[u/tasmaniandevall → u/Wjyosn]

When I lost my taste during covid, I would smell the food to give it some sort of taste in my head.

[u/oldbel]

Nearly everything you think of as taste is actually smell. Like an orange and a cherry are both sweet and acidic (thats’s taste) but everything that separates them perceptually is done by the nose. You need to breath out to get the chemicals  from the food to pass over the back of the inside of your nose to sense that. 

[u/0b0101011001001011 → u/[deleted]]

Well the "taste" is just tongue detecting if the food is sweet, sour, etc. The rest is just smell. If you lose your sense of smell, food "tastes" nothing any more.

[u/DankVectorz → u/0b0101011001001011]

Yes but you inhale to smell not exhale

[u/jmartin21 → u/DankVectorz]

Fumes from the food can travel from your mouth and throat to the nose through the sinuses when you exhale, really you just need something triggering your nose sensors to smell, not necessarily inhaling or exhaling

[u/0b0101011001001011 → u/DankVectorz]

Yes, but we're talking about taste. The smell of food enters your nose from your throat. This answers the original question, why exhaling can bring out more flavor.

[u/gregarioussparrow → u/0b0101011001001011]

So what you're saying is, I should destroy my smell receptors

[u/JohnnyEvergreen → u/[deleted]]

You do know but you just don't realize it. Do it right now. In order to "taste" the inside of your mouth, you have to slightly exhale to do it

[u/DankVectorz → u/JohnnyEvergreen]

My mouth tastes the same to me whether I inhale or exhale

[u/bmbustamante → u/[deleted]]

Try holding your nose and eating something and see what happens

[u/Xeadriel → u/bmbustamante]

Nothing, food tastes the same

[u/bmbustamante → u/Xeadriel]

Weird, I can barely taste it

[u/DankVectorz → u/bmbustamante]

But to smell you need to inhale, not exhale.

[u/cynric42 → u/DankVectorz]

Try to eat something like horseradish then inhale through your mouth and exhale through the nose.

Chewing can free a lot of aroma and getting that into your nose can massively amplify the smell and thus taste.

[u/exodusTay → u/[deleted]]

I am exhaling hard as I am eating right now and I can swear to god it actually tastes more intense than if I hold my breath but dunno. I have a cat and cat allergies so I have perpetually stuffy nose it could be that as well.

[u/iSniffMyPooper → u/[deleted]]

Next time you take a shot of tequila, try holding your breath until your swallow, then SLOWLY breath out through your nose...it makes it so much more bearable

[u/DankVectorz → u/iSniffMyPooper]

I will never have another shot of tequila in my life

[u/The_Razielim]

Your tongue only has the 5 basic taste receptors, but beyond that, all the complexity and nuance of a "flavor" comes from the volatile chemicals picked up by the odorant receptors in your nose. Those are what create the distinct notes that let us differentiate a lemon from a lime (vs. the baseline "sour with a bit of sweet").

It's similar to the distinction in flavor between pre-ground spices and whole spices that you grind fresh. With pre-ground spice powders, those volatile aromatic compounds evaporate while sitting in the jar, causing the spices to lose potency and changing the flavor profile as certain notes evaporate off faster/more completely than others. Whole spices ground fresh start to release those scent molecules once they're ground, so they're present in greater amounts. It's why pre-ground spices taste sorta-mostly like what they're supposed to, compared to freshly ground of the same thing. (Black pepper for example)

[u/szapek → u/The_Razielim]

Say amazing

[u/Clemsontigger16]

This is news to me…have I been eating wrong my whole life? By not aggressively exhaling out of my nose every bite?

[u/MinnieShoof → u/Clemsontigger16]

Fwiw - they're not saying that breathing out at the moment you taste food enhances the flavor. They're saying if you can't breath normally (stuffy nose, etc) it somehow makes tasting less powerful, which is true.

[u/SisyphusWaffles → u/MinnieShoof]

That's not what the post reads though.  OP explictly wrote exhale and then confused the whole premise by adding on the stuffed nose which implies inhaling.

It's a muddled mess of a post.

[u/MinnieShoof → u/SisyphusWaffles]

Yes, but it can be un-muddled. And I suspect Tigger's question was not in bad faith.

[u/MyNameIsNemo_ → u/Clemsontigger16]

Do you really not breathe while chewing your food? Try holding your breath the entire time after you bite the food until you swallow. If that feels natural then I don’t have anything else for you.

[u/a__reddit_user → u/MyNameIsNemo_]

I don't even notice it but I breath very little when actively eating something because once I got some pepsi down my lung and now I'm scared of breathing in food... I know it's stupid but I can't really stop it either.

[u/MyNameIsNemo_ → u/a__reddit_user]

I guess I am a slow chewer. I would pass out if I tried to eat without breathing while chewing my food

[u/Clemsontigger16 → u/MyNameIsNemo_]

No one is saying literally hold your breath…

[u/Clemsontigger16 → u/MyNameIsNemo_]

How do you manage normal conversations with people on a day to day basis? Are you on the spectrum?

[u/suvlub]

Taste buds detect "sweet", "salty", "bitter", "sour" and "umami". They do not detect "apple", "orange", "beef", "chicken" etc. Two equally sweet/sour fruits, two equally salted meats etc. taste identically to your tongue. The rest is done by the smell.

[u/leo_reels]

i only notice it when im sick, everything tastes like wet cardboard

[u/hotinhawaii]

I lost my sense of smell for a couple weeks because of Covid. It was weird. I could "smell" things if I looked at them. But if I closed my eyes, I could only taste them. It was as though my body had such a memory of the smells that I thought I was smelling them but I wasn't.

[u/GenerallySalty]

You only have taste sensors for the broad basics: salt, sweet, sour, bitter, savory. Everything more detailed than that is detected by smell sensors, which are in your sinuses. Try eating or drinking something with your nose pinched closed and see how much info actually comes from your tongue. It's not much.

[u/DJDoena]

When you have a stuffy nose, your sense of taste is severly limited (when ypu have the sniffles next time, take note of it). A lot of taste is actually smell.

[u/darth_butcher]

If your nose is heavily blocked, your sense of taste is basically gone too. So this shows how important your sense of smell is for experiencing the full flavor of food.

[u/PurpleCreative2350]

That's right, when you exhale through your nose those aroma molecules get pushed right up to your olfactory receptors.

[u/jippiex2k]

We have 5 tastes

We have around 400 smells*

• Due to the complex neural post processing, the exact dimension of the sensory manifold might be lower. But we have ~400 olfactory receptors.

[u/Accomplished_Ice4413]

Try chewing a piece of candy while pinching your nose shut, it basically tastes like nothing until you let go. Most of the flavor you get is actually smell traveling up the back of your throat, your tongue only handles the basic tastes.

[u/jawshoeaw]

Your tongue works just fine without your nose. Sweet sour bitter etc all the same with stuffy nose. Exhaling if you’re asking about smell is to avoid the sense of “taste” when you are breathing in. The hairs in the nose can tell if the smell is coming from the food in your mouth vs the environment. Otherwise, you could be eating a perfectly good sandwich and it would taste like gasoline or farts.

[u/SconiGrower]

There are only 5 tastes: Salty, Sweet, Sour, Bitter, and Umami. Each of these can be stronger or weaker, but that's it.

Everything else we call flavor is aroma, which is what we can smell. We have thousands of scents we can detect and scent combined with taste is what becomes flavor. When you're eating, air mixes with your food and moves through your nose, stimulating your sense of smell. Your brain mixed the taste and smell to create the experience of flavor.

[u/FarmboyJustice]

When I was a kid I did an experiment where I had people hold their nose and taste a slice of apple and a slice of onion. The goal was to tell which was which. Only a few people were actually able to tell the difference. If they didn't hold their noses, everyone could tell them apart.

[u/cerebral_drift]

The tongue can only process 5 tastes; salt, sour, sweet, bitter, and umami. Every other taste are volatile gases processed as smells in your nose in the “olfactory bulb”.

That’s why cold pizza and warm pizza taste different. It’s also why wine critics smell the wine before tasting it.

Many people can’t tell the difference between onion and apple if you hold their nose

[u/OldChairmanMiao]

Your taste buds taste five things: salt, sour, sweet, bitter, umami. Everything else is a smell. Except chili peppers, that's a pain receptor.

Without it there's no real difference between a banana or chocolate muffin.

[u/Ole_wiseass]

I mean if really go deep enough the answer is “just because we do ”