Water activity (aw) is a measure of the availability of water in a substance for microbial growth and chemical reactions. It is a crucial factor in food science, pharmaceuticals, and various industrial applications, as it directly influences the stability, safety, and quality of products. Unlike moisture content, which measures the total amount of water in a product, water activity measures the proportion of free water that can participate in biological and chemical processes. A higher water activity value typically indicates a greater potential for microbial growth, leading to spoilage and reduced shelf life. Therefore, controlling water activity is essential for preserving product integrity and ensuring safety.