We offer two different sensors:

• The measuring chamber Due to the large sample volume, larger quantities can be measured within a short time. This enables a higher number of random samples to be drawn.
• The cell again is used for very small sample amounts. In addition, the sensor can be replaced here.
• Many products can be measured, such as butter, fruit mixtures, spices, granules, PVC, mushrooms, xylitol or seasoning.

With our aw value measuring instruments for food, the shelf life and quality can be secured and controlled.

The measuring device is a laboratory device and enables measurements in accordance with EN ISO 21807.

In the download area you will find the instructions for calibration and adjusting the water activity meter humimeter RH2.

FAQ:
What is the water activity?
Water activity is a measure of the free water available in a substance or product and its ability to support the growth of microorganisms such as bacteria, yeast and mold. It is defined as the ratio between the vapor pressure of water in a substance and the vapor pressure of pure water at the same temperature and is expressed as a dimensionless value between 0 and 1.

Why is the aw value measuring device important for food?
Water activity is an important factor in food preservation and quality control. Foods with high water activity, such as Fresh fruits and vegetables, for example, are more susceptible to spoilage and deterioration because the water in the food provides an ideal environment for microorganisms to grow. In contrast, foods with low water activity, such as B. Dried fruit, can be kept much longer, since the low water activity makes it difficult for microorganisms to grow.

Can the aw value measuring device also be used for meat?
Yes, the huimeter RH2 the water activity meter for food is used for meat. Fresh meat has the highest water activity. The preservation reduces the availability of moisture for the microorganisms.

What is Equilibrium Moisture?
Equilibrium moisture content is the moisture content that a material or substance will absorb and retain at a given temperature and relative humidity when in a steady state. As relative humidity increases, the material absorbs moisture until it reaches equilibrium. As the relative humidity falls, the material sheds moisture until it regains equilibrium.

What is the optimal aw value?
The optimal value depends on the product. Each food has its own limits that determine when mold growth is possible.

Benefits

• Aw value, relative humidity, absolute humidity, dew point, equilibrium moisture content
• Fast adjustment behavior
• Long-term stable humidity and temperature sensors
• Easy data storage on the portable moisture meter
• Optimal documentation of your quality
• portable handset
• High measuring accuracy

Handling and measurement process

The simple handling guarantees a cost-saving and error-free measurement of the activity of the water value of food. Simply fill the material into the aw value chamber and close it.

After an appropriate conditioning time (time period until a constant climate in the chamber is reached = moisture equilibrium) the water activity can directly be read off the display of  the humimeter RH2 water activity meter.

The time it takes to reach moisture equilibrium depends heavily on the material to be measured and the temperature. Hygroscopic materials such as cornflakes assimilate in a much shorter time than whole corn kernels. In this context, it is important that the samples have the same temperature as the measuring device or the measuring chamber - high temperature differences lead to a longer conditioning time. This material-dependent conditioning time is a physical phenomenon and cannot be shortened artificially. Generally, the conditioning time is from 5 minutes to about an hour.

The moisture equilibrium is achieved when the displayed measuring value is no longer changing for a period of several minutes (e.g. 10 minutes, changes less than 0,002 aw).

In this Video we explain how the aw value measuring chamber itself is calibrated and adjusted. For this you need the appropriate calibration solution (certified calibration ampoules).

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