If you’ve ever taken a bite out of a lemon, you already know they pack some serious sour power. This is because they contain citric acid, which is a weak organic acid found in many fruits and vegetables.

True to their name, citrus fruits have particularly high concentrations of citric acid. Lemons and limes have even higher concentrations of citric acid than their sweeter citrus cousins, such as oranges and grapefruits.

When you take a bite of a lemon — or any food — your taste buds interpret what you taste. Like little receptors, your taste buds gather information and send it to your brain.

When food comes in contact with the taste buds, they send a message to your brain telling it whether the food is sweet, salty, bitter or sour.

The tip of your tongue senses sweet and salty foods, while the back of your tongue senses bitter flavors. When you bite into a lemon, the citric acid activates taste buds along the sides and center of your tongue. These taste buds let your brain know when something is sour.


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    • We thought that might help our Wonder Friends “see” how sour lemons can be! Have you ever made a face when you’ve tasted something super sour, soccer101?

    • You’re welcome, Lucie! We’re glad you got to explore this Wonder of the Day®, today and learn a little more about how taste buds work! :-)

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Have you ever wondered…

  • Why are lemons sour?
  • What is citric acid?
  • What are taste buds?

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Try It Out

Put your tongue to the test and create a taste bud map. Sample a bit of sweet, salty, sour and bitter and report back on what tickles your taste buds.

Try this taste test with a friend or a family member, and see if your results match up.


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If you enjoyed today’s wonder, be sure to visit EconEdLink to dive deeper into The Lemon Story!


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