But smell, like other human capabilities, is variable, subjective and exhaustible. Even the most highly trained noses become fatigued with exposure to a variety of aromas. Like hearing and eyesight, olfactory acuity varies from one individual to the next and even varies from day to day depending on health, weather and other factors affecting humans. While ability to smell may be hard to gauge from one individual to the next, the capacity for an odor to emanate in a given environment is a concrete and measurable phenomenon. While it may seem mysterious, smell does not just happen.
Volatile components release odor molecules into the air.
Mammals inhale these elements and, if they register with our receptors, detect the odor. If we are familiar with the odor, we recognize and respond to it. The average wine drinker's ability to recognize off odors is as hard to predict as the quality of next year's harvest, but there is no getting around the fact that it matters. In recent years, the wine industry, seeking to increase consistency and consumer loyalty, has upped its investment in quality-control programs. The success of these programs has been difficult to gauge so far, but in the face of an expanding wine market, increased competition worldwide and a future likely to bear more grapes than ever before, there is no turning back.