Smell, Taste and Flavor

By Stephanie Feuer

Smell and Flavor

Until I lost my sense of smell, I didn’t think much about how integral our sense of smell is to the perception of flavor. Your mom knew this instinctively when she told you to hold your nose to make to easier to swallow icky-flavored medicine. And you’ve probably noticed the muting of flavor when you have a stuffy nose from a cold or other respiratory infection.

Smell is the component in the ability to detect flavor. Researchers say that 75% to 95% of what we think of as the taste of our food actually comes from our sense of smell. A fun way to test this how smell influences flavor is to get a handful of jellybeans. Hold your nose and chew one– you’ll taste the sweetness, but won’t be able to identify the flavor until you free your nose.

What we commonly think of as smell—sniffing an odor through the nose—is called orthonasal olfaction, and is only part of the process of smelling.  

The second way of smelling happens in the mouth, and is responsible for our ability to detect flavor. Called retronasal olfaction, it starts with chewing, which sends odor molecules from the mouth to the nose via the throat. When these odor molecules hit the olfactory receptors, the brain uses that input to create flavor.  

Flavor and Taste are not the same

While we often use the words taste and flavor interchangeably, true taste is what happens on the tongue, while flavor is amalgamated in the brain. The taste receptors on our tongues detect the basics: salt, sweet, bitter, sour, and umami (savory). Some scientists argue for the addition of fat, calcium and metallic.

Flavor is complex

Flavor is what our brains create from taste and smell, as well as a host of other sensory elements. Because our brains use vision to make predictions, appearance matters. Not only is a well-plated dish more appealing, visual information can change our perception of what we are tasting. When researchers added a tasteless odorless red dye to white wine, they fooled a panel of wine experts into thinking they were tasting a red wine.

Temperature, texture, mouthfeel, spiciness, and even sound also all contribute to the experience of flavor. Personal factors come into play as well. Age, smoking history, general health, pregnancy, colds and allergies, genetics and cultural experiences all add to the experience of flavor. It even matters who you are eating with; food seems to taste better when we eat with other people.

So while true taste is limited to the tongue and mouth, flavor is a multisensory experience, with smell a major contributor.