Maize [N=33963]

Water activity (aw)

Water activity (aw) is the measurement of how tightly water is bound, structurally or chemically, in a product. It is defined as the ratio of the water vapor pressure over a sample (P) to that over pure water (P0) : aw = P/P0 Cf. http://www.decagon.com/aqualab/questions.html