Supertasters typically have a higher density of fungiform papillae, mushroom-shaped projections on the tongue that contain taste buds.

WSJ: People Who Taste Too Much

Some experts say one way to tell if a person is a supertaster is to count the number of papillae in a small area after dying the tongue with food coloring, a test that can be done at home.

WSJ: People Who Taste Too Much

In the past we've seen a tongue-based computer interface or two, the BrainPort sight-via-papillae solution, and this week, at the American Chemical Society's annual meeting, researchers from the University of Illinois at Urbana-Champaign introduced a sensor about the size of a business card that detects and identifies fourteen common sweeteners -- including Splenda, Sugar in the Raw, and Sweet'n'Low.

ENGADGET: Electronic tongue tastes, identifies sweeteners so you don't have to