Why do people chew with their mouth open

Growing up, we're all taught the dos and don'ts of eating at the dinner table. No elbows on the table, no licking your fingers, cutlery in the correct hands at all times – these are just a few of the table manners that are drilled into us from day dot. Of course, the most important rule of all has always been to chew with your mouth closed. Until now, it seems.

That's because some scientists have turned the dining table rule book on its head with their latest statement, claiming that eating with your mouth open can actually make your food taste better. Nan, look away now!

"We've been doing it all wrong," Professor Charles Spence at Oxford University told The Telegraph. "Parents instil manners in their children, extolling the virtues of politely chewing with our mouths closed."

He went on: "However, chewing open mouthed may actually help to release more of the volatile organic compounds, contributing to our sense of smell and the overall perception."

For those who don't know (read: us), volatile organic compounds are chemicals that make up the smells and flavours in your food.

Granger Wootz/Blend ImagesGetty Images

But, as shocking as the revelation may sound to those dedicated to dining etiquette, the notion shouldn't be too hard to wrap our heads around – after all, anyone who has ever been on a wine tasting session will know that taking in a bit of air as you sip enhances the beverage's taste.

And that's not the only reason, as there's another sense that comes into play as far as flavour goes: sound!

"When it comes to sound, we like noisy foods – think crunchy, crispy. Both crisps and apples are rated as more pleasurable when the sound of the crunch is amplified," Spence pointed out. "To best hear the crunch of an apple, a potato crisp, a carrot stick, a cracker, crispbread or a handful of popcorn, we should always ditch our manners and chew with our mouths open."

If you want to go one step further on your journey to more flavour, Spence advises ditching cutlery altogether and eating with your hands, too. "Our sense of touch is also vital in our perception of food on the palate," he explained. "The research shows that what you feel in the hand can change or bring out certain aspects of the tasting experience."

Finally, he said: "While licking fingers after eating with our hands is never encouraged in polite circles, research would suggest we ought to consider scrapping the etiquette for utmost sensory enjoyment.

"Or consider only how pleasant it can be to lick the bowl with your finger when making a cake mix at home."

BRB, off to bake a cake...

I hope that people who know me well would describe me as an easy-going kind of gal. Generally relaxed, tolerant to a fault, I like trying new things and visiting new places. I’m low maintenance, naturally sociable, and I enjoy being around all kinds of people – with one exception.

Those who eat with their mouths open (or worse still, chew gum) are my Kryptonite, my achilles heel, the chink in my chilled armour. As such, greeted with the recent news that “chewing with your mouth open makes food taste better” – something about oxygen and flavour molecules, like swishing wine around a glass before tasting it – I can only respond that while that’s very interesting, such behaviour should be illegal, please and thank you.

The sound of wet mouth mastication is one of the only things in life that reliably tips me into blind fury, shattering my customary self-control in seconds as though someone has reached into my brain’s deepest circuitry and yanked all the wires at once. If you’re like me, you’ll be nodding vigorously right about now – but for those blissfully unaware of this peculiarity: it’s called misophonia and it’s a thing, OK?

Literally translating to “hatred of sound”, misophonia is basically an outsize fight-or-flight reaction to certain noises, most often those associated with eating, but ranging from sniffing to throat clearing and even pen-clicking.

More common in girls (tick), misophonia tends to develop in childhood or adolescence (tick) and to be associated with anxiety disorders (tick). It’s maybe something to do with mirror neurons, or connections between auditory and motor brain regions, or just a kind of neurological category error – whatever the origin, scientists agree that misophonia is as much a physical disorder as a mental one. And whatever their particular triggers, sufferers agree that it is, um, a real bore.

While anyone can find themselves struggling with misophonia, then, Neurotic Teenage Me was something of a sitting duck – so years later, when a little notification on one of those 23andMe tests popped up to tell me that I had a genetic marker for misophonia (as well as others for flat feet, and amazingly, a fear of public speaking), I felt somewhat vindicated. Tell me something I don’t know, doc, I said – quietly, to myself – as I shuffled along on my brick feet away from the guy snapping gum at the bus stop, a prisoner of my bafflingly specific genes.

It’s hard to explain to someone who doesn’t have misophonia themselves the effect that trigger sounds can have, but suffice to say that some sufferers go to great lengths to avoid them. When I was at secondary school, I went through a phase of not being able to eat with my family because of the noise – today I’m much less affected, but it’s not hard to see how a condition that sounds funny or eccentric might quickly cross over into something that affects your life and relationships.

While there’s no official criteria for diagnosing misophonia, some studies suggest that up to one in five people suffer to some extent, with less than one per cent grappling with the most severe symptoms.

Personally falling on the milder end of that spectrum, I’m rare but by no means alone in my haywire fight or flight reflex: obviously, someone eating toast loudly is not a threat, but try telling that to my otherwise robust limbic system.

One of the worst things about misophonia is plucking up the courage to talk about it. Over the years I’ve gotten better at coping as well as speaking up, but the very real fear of sounding mad or entitled is enough to keep lots of people from ever mentioning their misery. As such, consider this article a kind of public service announcement – after all, if that one in five statistic is anything to go by, chances are that there will be at least one person with some degree of misophonia at any given dinner table.

While conventional wisdom agrees that it is bad manners to eat with your mouth open, misophonia sufferers aren’t worried about being offended – rather, having their brain’s most primal panic response triggered every time you load your fork. Weird? Yes! Exhausting? You betcha.

Forget manners, f**k decorum – but for their (my) sake, please don’t spend all night chewing performatively to “let the air in” now that science is on your side. I’m no chemist, but I promise that the tiny amount of extra flavour you might gain is no match for the cringing, trapped fury of the person sitting next to you.

Going forwards, perhaps an adaptation of the old smoking-or-non-smoking table system might appease both sides of the debate; restaurants could have open-mouth and civilised (sorry, closed-mouth chewing) areas: “Table for four, closed-mouth please.”

I’ll take my minutely less flavourful compounds over the din of chewing any day, thanks.

Ty Larsen, Columnist
October 18, 2020

You don’t want to be the person at a restaurant chewing with your mouth open, and getting food everywhere. People who chew with their mouth open are lacking some table manners, or they don’t care about food potentially coming out of their mouth. Imagine if someone is eating dinner with their girlfriend’s parents, but they chew with their mouth open. That would leave such a bad impression on her parents. Nobody wants to see food fly out of your mouth.

According to Dr. Heidi Grant, chewing with your mouth open is the normal way you are  supposed to chew. Research shows that chewing with your mouth open makes you feel more powerful, and that you are less sensitive to what is happening around you. So, even though you might find it disrespectful, it makes the person chewing with their mouth open perceive themselves as having power in the scene. Chewing food with your mouth closed is more satisfying and much easier to enjoy.  You can also potentially eat less when you chew with your mouth open, because you enjoy your food more and are more satisfied when your mouth is closed.

Eating with your mouth open might be the right way to eat, but it’s not the respectful way to eat.