Sour foods, like lemons, activate a proton channel in taste buds to tell the brain, “That is sour.” [Credit: Nancy R. Gough, BioSerendipity, LLC]

How the Tongue Senses Sour

Taste buds get turned on by protons.

Sour-tasting foods are acidic. Acids have a lot of free protons. Those protons get transported into the taste buds cells that detect sour and make those cells become acidic. This sets off a chain of electrical events, involving 3 other proteins that also transport ions, in particular potassium ions, sodium ions, and calcium ions. The outcome is release of neurotransmitters that stimulate the nerves connected to the taste buds to signal the brain: Sour!

Check out the video of how this happens based on research from the Liman lab at the University of Southern California.

Read more about the research in “Liman Lab Reveals Mechanism of Sour Taste” and “Genetically Engineered Mice Reveal Mechanism of Sour Taste.”

The Startup

Get smarter at building your thing. Join The Startup’s +787K followers.

Sign up for Top 10 Stories

By The Startup

Get smarter at building your thing. Subscribe to receive The Startup's top 10 most read stories — delivered straight into your inbox, once a week. Take a look.

By signing up, you will create a Medium account if you don’t already have one. Review our Privacy Policy for more information about our privacy practices.

Check your inbox
Medium sent you an email at to complete your subscription.

Nancy R. Gough, PhD

Written by

Ph.D. scientist with a passion for scientific communication and > 20 years editorial experience

The Startup

Get smarter at building your thing. Follow to join The Startup’s +8 million monthly readers & +787K followers.

Nancy R. Gough, PhD

Written by

Ph.D. scientist with a passion for scientific communication and > 20 years editorial experience

The Startup

Get smarter at building your thing. Follow to join The Startup’s +8 million monthly readers & +787K followers.

Medium is an open platform where 170 million readers come to find insightful and dynamic thinking. Here, expert and undiscovered voices alike dive into the heart of any topic and bring new ideas to the surface. Learn more

Follow the writers, publications, and topics that matter to you, and you’ll see them on your homepage and in your inbox. Explore

If you have a story to tell, knowledge to share, or a perspective to offer — welcome home. It’s easy and free to post your thinking on any topic. Write on Medium

Get the Medium app

A button that says 'Download on the App Store', and if clicked it will lead you to the iOS App store
A button that says 'Get it on, Google Play', and if clicked it will lead you to the Google Play store