When you chew mint gum for a while, the taste seems to disappear. Most people think the mint smell is all gone.

But scientists in Britain found something different. They checked the air from people's noses while they chewed. The mint smell was still there! What was gone was the sugar. When the sweetness went away, the mint taste also felt weaker. Taste and smell work together in our brain.

Why does chewing gum lose its flavor? You might guess that the mint aroma simply runs out. In 1999, researchers at the University of Nottingham tested this idea.

Trained tasters chewed mint gum while the team measured three things at the same time. They checked the amount of sugar on the tongue and the amount of mint aroma reaching the nose. They also asked the tasters how strong the mint flavor felt.

The results were not what most people would expect. The mint aroma kept coming out slowly for a long time, but the sugar disappeared much faster. And the tasters' sense of mint faded together with the sugar. So the brain seems to judge flavor by combining taste and smell.

Most people assume that chewing gum goes bland because the mint aroma has been used up. In 1999, researchers at the University of Nottingham put that assumption to the test. While trained panelists chewed commercial mint gum, the team tracked three variables at once: the concentration of sucrose in the saliva on the tongue, the amount of menthone, a key mint aroma compound, reaching the nose with each breath, and the panelists' moment-by-moment ratings of mint flavor.

In both gums tested, sucrose was released quickly and soon declined, while menthone kept coming out for much longer. The panelists' sense of mint faded along with the sugar. It did not track the aroma, which was still there. The most likely explanation is that the brain combines taste and smell, having learned through repeated experience that mint and sweetness go together, so when one partner disappears, the other seems weaker.

The tasters were a small panel of trained assessors, and ordinary gum chewers might respond differently. Some people report that adding sugar to tasteless gum brings the mint back, though no one has tested this rigorously. This may also explain why a little sweetness can lift the aromas in a dish.