RH2-AW Aw value/activity of water measuring chamber

The Aw value or water activity value is an indicator for unbound water content in products such as food products in particular.

For the measurement of humidity in food not only the absolute humidity is important, but also the proportion of unbound water. In fact, the proportion of unbound water affects the growth of microorganisms and bacteria and can has thus have an effect on the shelf life as well as the overall quality of the product.

The formula for calculating the Aw value is as follows: relative humidity/100%.

The AW value measurement chamber quickly and accurately determines the AW value of salt, spices, granules, dried fruits, flours and many other foods. In addition to foods, plastic granules and similar materials can also be measured.

A big advantage of the Aw value determination is that no calibration has to be performed for each individual test material. This saves costs and allows quick testing of different kinds of samples without having to change settings.

The AW value will be shown on the RH2 display as soon as a moisture balance in the measuring chamber has been established. The equilibrium settles faster when the temperature differences between the sample, the measuring camera and the environment are lower. Generally the adjustment may take 5 to 60 minutes, depending also on the type of material to be measured.

The AW value sensor shown on this page can only be used in conjunction with an RH2 moisture meter.

N.B.: The AW chamber must not be used for juices, acid and alcohol-containing products!