Humimeter RH2 aw value measuring device 0 °C to +50 °C Food

The freely available water in food is referred to as water activity and is measured as Aw value. This measurand is a quality factor that depends on the vapor pressure of the water in the material, the prevailing temperature and the ambient vapor pressure of the water.

The combination of the Humimeter RH2 and the Aw-value measuring device enables a quick and easy determination of the water activity. The measuring chamber offers a large sample volume so that even larger quantities can be measured quickly.

The mobile laboratory measuring device is suitable for the determination of water activity and output of the Aw value for food with data logger. It is suitable for measuring materials such as butter, fruit mixtures, spices, granulates, mushrooms, xylitol, flour, cookies or even sausage, as well as all other foodstuffs for which a check of the Aw value is required.

The simple operation of the measuring device enables a cost-saving and error-free procedure for determining the Aw value for food. The sample is filled into the measuring chamber and sealed. A sufficiently long adjustment time is necessary so that a constant moisture equilibrium is established in the chamber. The Aw value can be read directly from the Humimeter RH2 Aw value measuring instrument.

The duration for the adjustment of the moisture equilibrium (equilibration time) depends essentially on the sample material and the temperature. Hygroscopic materials such as cornflakes equilibrate faster than whole corn kernels. It should also be noted that large temperature differences between the sample material and the measuring chamber can extend the equilibration time. As a rule, adjustment times between 5 minutes and one hour are realistic.

Humidity equilibrium can be recognized by the fact that the display no longer changes (usually less than 0.002 aw) over a period of a few minutes (e.g. 10 minutes).

What is water activity and why is it important for food?

The water activity (aw) indicates how much free water is available in a product for microbial, chemical or physical processes. It lies between 0 and 1, with pure water having a value of 1.0. Foods with an aw value below 0.6 are virtually resistant to microbial growth.

7 reasons why water activity is crucial:

1️⃣ Inhibit microbial growth - A low aw value prevents the growth of bacteria, yeasts and molds.
2️⃣ Extend shelf life - Food stays fresh longer, especially during long-term storage.
3️⃣ Increase food safety - Protection against salmonella, E. coli and listeria.
4️⃣ Improve preservation - techniques such as drying and salting help to preserve food.
5️⃣ Preserve texture - crispy products remain crunchy, soft foods retain their consistency.
6️⃣ Avoid loss of quality - fewer chemical reactions such as oxidation or browning.
7️⃣ Optimize packaging - protects against moisture and preserves product quality.

Precise measurement with the humimeter RH2

With the humimeter RH2, you can measure water activity quickly and reliably. Two sensors adapt perfectly to the material - for maximum measuring accuracy and maximum product quality.

Link: What is water activity

Food