The Reason Orange Juice Tastes Horrible After Brushing Your Teeth

There are some things in life that just go together, like hot fudge on a sundae and ketchup on a hot dog. Then there are combinations we force together, like peanut butter and mayo, and as weird as they sound, actually end up being pretty good. Certain combinations though, no matter how hard we try, will never work. Take the morning ritual of brushing your teeth before enjoying a glass of orange juice. If you've done it, you know that it's quite an unpleasant experience. Don't worry about checking the expiration date on your carton, though — it has nothing to do with your juice. It's a certain ingredient in your toothpaste that makes orange juice taste so bad.

Once your toothpaste hits your teeth, it starts to create an intense foaming action. That foaming action is caused by the compound sodium lauryl sulfate (SLS), which is a surfactant that can be found in shaving cream and household cleaners, and according to Live Science, acts as a "detergent for your mouth." Why do those detergent bubbles in your mouth affect the flavor of orange juice? 

This unpalatable phenomenon is due to the effect of SLS on our taste buds. If you were to stick your tongue out in the mirror, you would find tons of tiny little bumps on each taste bud. Those tiny bumps are our taste receptors. They allow us to enjoy the sweet, bitter, sour, salty, and umami flavors of everyday food and drink. If you don't already know, orange juice is loaded with sugar. It's a flavor our taste receptors can't help but love, but when SLS bubbles up in our mouth, it inhibits our taste receptors' ability to taste the sweetness of orange juice. The American Chemical Society explains that SLS also destroys a compound in our mouth, known as phospholipids, whose main job is to reduce the taste of bitterness. When the phospholipids are destroyed, it leaves our taste receptors wide open to the citric acid in orange juice, which is inherently bitter. 

With both factors combined, it's no wonder a sweet glass of orange juice is turned into a bitter bomb.