The Olfactory Factor


How can a cheese that yields such a strong malodor taste so good?

Take Limburger, for example. The bacterium used to ripen the cheese (Brevibacterium linens) produces such a striking sulfuric smell that it’s a wonder that someone ever decided to eat it. In fact, to this day I hear many people refuse a taste based on its notorious scent. But this is an olfactory prejudice. For when you put a slice of Limburger in your mouth, the odor actually dissipates completely, and the flavor is quite mild.

How can this be? This is because our perception of a smell changes as we eat. [1]

When you inhale before eating, scents directly travel to receptors in the nasal passageway, which send signals (i.e., “Stinky!”) to various parts of the brain.

But inhaling while chewing produces different results. Chewing releases scents that also travel to receptors in the nasal passageway, but via the throat (called retronasal inhalation). Again, signals are sent to various parts of the brain. But as you chew, taste receptors are simultaneously transmitting signals to other parts of the brain. But in one part of the brain, called the anterior insula, signals of scent and taste co-occur. Here scent and taste cannot be perceived distinctly. Instead, the two perceptions integrate. No other senses overlap like this. This is flavor country.

A foul odor and a sour taste, for example, may yield a mild and tangy flavor. Just because a cheese smells bad, doesn’t mean it stinks.

[1] Bakalar, N. Sensory science: Partners in flavour Nature 486, S4–S5 (21 June 2012)