Imagine the scent of freshly brewed coffee wafting through the house as they brew. How does this smell get carried to people?

Heat converts many substances into their volatile form. Because only volatile molecules in the form of gas carry odor, it is easier to smell hot foods than cold ones.

Aroma and Taste Perception

Hot coffee is much easier to detect than cold coffee. Relatively large molecules such as proteins, starches, fats, and sugars are too heavy to be airborne, so their odors are not easily noticed.

Lighter molecules capable of becoming volatile are physically detected by the olfactory epithelium by one of two pathways: (1) directly through the nose and/or (2) during eating when they enter the mouth and flow retro-nasally, or toward the back of the throat and up into the nasal cavity.

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