The environment in which the taste panel evaluates foods or beverages is carefully controlled. Panelists are usually seated in cubicles or booths, and the food is presented in a uniform fashion. Food samples must be of the same size (enough for two bites), from the same portion of the food (middle versus outside), equally fresh, at the same temperature, and presented in containers or plates that are of the same size, shape and color. White or clear containers are usually chosen so as not to influence panelists’ perceptions of the food’s color. Care is taken that the lighting in the room is uniform and that the ambient temperature is comfortable and the surroundings quiet and odor-free.
Midmornings or mid-afternoons are considered the best times for sampling, because at these times people are not usually overly hungry or full. Samples are randomly coded and are kept to a reasonable number to avoid “taste fatigue.” Room-temperature water or plain bread is made available for use between samples to prevent carryover tastes, and at least a 30-second rest period is scheduled between samples. Paper towels or napkins are provided, and since swallowing the food or beverage influences the taste of subsequent samples, small containers into which samples may be spit are provided.