Take a lick of vanilla ice cream: sweet and cool, as expected, but with little fragrance. Surprising, since vanilla normally has such a distinctive scent. But wait a beat; then suddenly there’s the familiar aroma, the one that, if you go back long enough, schoolgirls once used as perfume.
That wait was just long enough to allow all hell to break loose inside your mouth. The ice cream is now literally exploding. Air bubbles are bursting from the heat of your tongue. A volatile compound, in this case vanillin, is boiling. Sweet scents are wafting their way up your nasal cavities, where olfactory cells send your brain the belated good news.
Take another lick, and touch off another explosion.
Ice cream is virtually the only food we eat frozen, which means that its flavor, which we define as a composite of taste and smell, is only fully released upon melting, explains Arun Kilara, a 43-year-old professor of food science at Penn State and one of the world’s acknowledged authorities on ice cream. Kilara is the leader and principal lecturer of an annual two-week industry seminar on ice cream run by Penn State’s Department of Food Science. The seminar was started a century ago as a winter course on milk processing for local dairy farmers. Today it is widely regarded as the foremost forum on the science of ice cream, and it has been presented to thousands of dairy professionals on four continents and to tens of thousands more in the form of a correspondence course. Perhaps its proudest graduates are a pair of ice cream devotees named Ben and Jerry, who founded their eponymous business after taking the correspondence course. Years later they shut down their Springfield, Vermont, plant for two days, so that all 100 employees, from floor cleaners on up, could attend a special version of the course, taught right on the premises.
