Source: wikibot/water-activity
= Water activity
{wiki=Water_activity}
Water activity (aw) is a measure of the availability of water in a substance for microbial growth, chemical reactions, and biochemical processes. It is defined as the ratio of the partial vapor pressure of water in a material to the partial vapor pressure of pure water at the same temperature. Water activity values range from 0 to 1, with pure water having an aw of 1.0.