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Why Do People Scrunch Up Their Faces After Tasting Something Sour?

Eating Something Sour

Have you ever eaten something sour, and your face scrunches up? Some people can stop their face from doing this, but you still have the natural reflex to scrunch up your face. There is nothing funnier than feeding a baby something sour. Babies don’t realize that they are making funny faces when they eat something sour, and they often don’t care. This is what makes it so amusing. You know that this happens, but have you ever wondered why do people scrunch up their faces after tasting something sour?


Scientists don’t know for sure what causes this automatic reaction, but they believe that it involves three things, protons, vitamin C, and the fact that our ancestors enjoyed a tropical buffet when they lived in trees. This means that the cause could go back thousands and thousands of years.


The sour taste in many fruits has a direct link with acidity. The sourness you experience is your taste buds, letting you know that there are loose protons in your mouth. Everyone knows that protons aren’t sour, but as our bodies have evolved, we have interpreted them as being sour.

Vitamin C

In order to survive, we need to have vitamin C. Without it, our cells and tissues cannot function properly. Also, history has proven that without enough vitamin C, humans can develop scurvy, which is a potentially fatal disease. Humans may be the most evolved creatures on the planet, but we do have our downfalls. Most creatures on Earth can create their own vitamin C, but humans today cannot. About 61 million years ago, our ancestors were able to make their own vitamin C.

Over the years, the genes that coded for vitamin C synthesis mutated. This is because there were so many sources of vitamin C around, and these sources were our ancestor’s primary source of food. With them consuming enough vitamin C each day, they no longer needed to synthesize it themselves. It isn’t like this change happened overnight. It took centuries and centuries of evolutionary changes for this change to occur. Because the vitamin C sources were so abundant during all these years, it happened slowly, but it did happen. This left humans today without the ability to create their own vitamin C. When you think about it; our ancestors are responsible for scurvy.

A Taste For Sour

Another mystery is why we like what we like. Some people love the taste of sour foods, and some people cannot stand it. Those who hate the sour taste aren’t fans of lemons, limes, and oranges. Everyone’s taste buds react the same way to the sour taste of their food, but according to scientists, it is the way our brains perceive the taste of the food that makes us either like it or hate it. This isn’t only true with sour foods; this is the case with any kind of food or drinks that you like or hate. You love a food that someone else hates because your brain interprets it differently.

Back To the Question At Hand

Now that you know how vital vitamin C is to us, how we lost the ability to make our own, and why we perceive the same tastes differently, it is time to get back to the question at hand. Why do our faces pucker up when we eat something sour. Unfortunately, science doesn’t have a definitive answer to this question. They do have theories, but none of them have been proven. The most common theory is that it is a rejection response. The sour taste causes your body to produce a natural signal letting you know that what you are eating is sour. While there is no scientific evidence to back this up, it is the consensus among most scientists.

No Studies?

You may be wondering why haven’t they performed studies to prove the theory? The answer is simple. We know that our faces pucker when we eat something sour, but what would a study prove. Would it change the way we live? Would it save lives? Scientists have more important live-saving research to focus on. Trying to get to the bottom of the face scrunching isn’t going to change the world, so there is no need to do any further research. Many scientists have similar theories, which is enough.

Automatic Response

We will need to simply accept the fact that the face scrunching is an automatic response. This doesn’t mean that it still isn’t funny to see a baby scrunch their face when eating something sour. For some reason, parents find it hilarious. There are plenty of videos on YouTube and Facebook of babies after baby eating something sour. When an adult does it, it isn’t too funny. When a baby does it, it is hilarious.

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