What is retronasal olfaction?

Retronasal olfaction is the process by which odorants (smelly molecules) enter our smell receptors from our mouth rather than our nose. This typically happens during eating or drinking, where smells travel backward through the mouth and up through the throat to the olfactory receptors at the back of our nose. This process is crucial for experiencing flavors and is a significant contributor to our sense of taste. In contrast, orthonasal olfaction occurs when we inhale and smell something directly through our nose 1.