Why do peppers taste hot?
For grown-ups: the science
Peppers taste hot because capsaicin makes tiny feelers in your mouth send a heat message to your brain.
Capsaicin activates TRPV1 heat- and pain-sensitive sensory receptors, especially in oral tissues. It is concentrated mainly in pepper placental tissue, the pale inner tissue where seeds attach, rather than in the seeds themselves. The brain interprets this receptor activity as burning heat, and it can trigger tearing and other protective responses.
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Transcript
A red pepper sits on the cutting board. Why does it make your mouth feel hot?
Some peppers make a chemical called capsaicin. It is strongest in the pale parts that hold the seeds.
Capsaicin touches tiny feelers in your mouth. Those feelers usually notice real heat.
Your brain gets a heat message, even when the pepper is not hot from cooking. That spicy feeling can make your eyes water.
So peppers taste hot because capsaicin makes your mouth send a heat message to your brain.