This week it’s a look at saliva with America’s funniest science writer, Mary Roach, author of Gulp: Adventures on the Alimentary Trail. The Sterns are at the Blue Scorcher Bakery Café in Astoria, Ore., and we learn which salts are really worth the money with salt merchant Mark Bitterman, author of Salted: A Manifesto on the World's Most Essential Mineral.

Broadcast dates for this episode:

• April 6, 2013 (originally aired)
• March 28, 2014 (rebroadcast)