Water activity (aw) refers to the amount of free water that is available in food for microbial growth and useful in predicting the growth of bacteria, yeasts and molds. By measuring the water activity of food stuffs it is possible to determine which micro organisms will be able to develop.

Water activity also affects the textural properties of foods ,foods with normally low aw have texture attributes describes as crisp and crunchy, where as high levels may change the texture to soggy.

A variety of microorganisms can grow in food products, and each microorganism can survive in different water activity ranges. Water activity is often used as a way to preserve foods and gain a longer shelf-life.

Most food falls within a water activity range of 0.2 to 0.99 the lower the aw value, the more “dry” a food item is considered. Water activity can be controlled by using various additives (humectants) by using packaging materials and storage conditions. Water activity influence microbiological,chemical and enzymatic stability of perishable products such as foods,grains,seeds etc.


Benchtop Model:

  • 4-channel benchtop display unit for measurement of water activity, relative humidity and temperature
  • AW Quick function for fast measurement results (typically 4-5 minutes)
  • Updates with functional enhancements
  • 4 USB ports (e.g. for mouse and keyboard)
  • Automatically generated measurement report after every measurement
  • Remote access by a normal browser with the PC or Tablet
  • Sharing protocols via E-Mail or downloading it with the PC

Portable Model:

  • Handheld instrument for measurement of relative humidity and temperature and calculation of water activity
  • AW Quick function for fast measurement results (typically 4-5 minutes)
  • Audible alarm to indicate end of measurement
  • Saves up to 10’000 data records with %rh, °C, date and time
  • Battery charging function


In many situations it can be very useful to measure water activity in production or storage rooms, e.g. inspection of bulk materials to ensure they meet specifications.

Water activity measurements in production processes: random checks of cheese, meat, tobacco, building materials, animal feeds, bakery products, paper, medicines, horticulture, agriculture, etc.


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