A: Our taste buds (the receptors found in the bumps on our tongue) react to compounds in foods, juices and other liquids. The compounds communicate with our tastebud receptors and tell them what to taste, whether that’s sweet, salty, sour, bitter or umami (savoury). When we brush our teeth, toothpaste starts to foam because of the compound Sodium lauryl sulfate (SLS) which cleans our teeth. SLS makes our taste buds more sensitive to bitter and less perceptive of sweet. Orange juice has a lot of bitter citric acid, but normally that’s masked by its added sugar.
Nothing to worry about though—the effects of SLS last only a few minutes. Saliva should wash away those toothpaste compounds, so you can enjoy sweetness again. Wait a few minutes after brushing your teeth before you sip on a glass of OJ. Your taste buds need time to adjust.