MATHEMATICS OF A LADY TASTING TEA REVISITED

The British Standards Institution and the International Standards Organization specify that when mixtures of tea and milk are to be evaluated sensorially, the tea should be added to the milk. Four cups of tea prepared by pouring the tea into the cup first (TIF) and four cups prepared by placing the milk in the cup first (MIF) were presented to 155 panelists in the dark. They were instructed to select by taste the four cups containing the MIF tea. The frequency of correct selection was well above the chance level, indicating that the panelists had detected a difference in flavor. The same task was performed by 131 panelists except they evaluated the tea in light. The panelists were not highly trained tea tasters; in fact, most were not regular drinkers of hot tea. Notwithstanding that, their discriminating power was sufficient to resolve the subtle differences which did exist.