Why Coffee Doesn't Taste as Good as It Smells

Scientists Discover Coffee Is Smelled Two Different Ways

The reason coffee doesn't taste as good as it smells is because saliva ruins many of the molecules that contribute to the aroma.
The reason coffee doesn't taste as good as it smells is because saliva ruins many of the molecules that contribute to the aroma. Glow Images, Inc, Getty Images

Who doesn't love the smell of freshly brewed coffee? Even if you can't stand the flavor, the aroma is tantalizing. Why doesn't coffee taste as good as it smells? Chemistry has the answer.

Saliva Destroys Coffee Flavor Molecules

Part of the reason coffee flavor doesn't live up to the olfactory hype is because saliva destroys nearly half of the molecules responsible for the aroma. Scientists have found 300 of the 631 chemicals involved in forming the complex coffee scent are changed or digested by saliva, which contains the enzyme amylase.

Bitterness Plays a Role

Bitterness is a flavor the brain associates with potentially poisonous compounds. It's a sort of biochemical warning flag that discourages indulgence, at least the first time you try a new food. Most people initially dislike coffee, dark chocolate, red wine, and tea because they contain potentially toxic alcohol and alkaloids. However, these foods also contain many healthy flavonoids and other antioxidants, so palates learn to enjoy them. Many people who dislike "black" coffee enjoy it when it's mixed with sugar or cream or made with a tiny amount of salt, which removes the bitterness.

Two Senses of Smell

Professor Barry Smith of the Centre for the Study of the Senses at the University of London explains the primary reason coffee doesn't taste like it smells is because the brain interprets the aroma differently, depending on whether the sense is registered as coming from the mouth or from the nose.

When you inhale a scent, it goes through the nose and across a sheet of chemoreceptor cells, which signal the odor to the brain. When you eat or drink food, the aroma of the food travels up the throat and across the nasoreceptor cells, but in the other direction. Scientists have learned the brain interprets the scent sensory information differently, depending on the orientation of the interaction.

In other words, nose scent and mouth scent are not the same. Since flavor is largely associated with scent, coffee is bound to disappoint. You can blame your brain.

Chocolate Beats Coffee

While that first sip of coffee may be a bit of a letdown, there are two aromas that are interpreted the same way, whether you smell them or taste them. The first is lavender, which retains its floral scent in the mouth, yet also has a mildly soapy flavor. The other is chocolate, which tastes as good as it smells.