Climate precision humidity analyser with data logger 

for laboratory, climate and environmental applications as well as aw-value measurements

Required accessories: aw-value measuring chamber set art. no. 13700 or aw-value 

measuring cell set art. no. 14500

Analyzer for determining water activity (aw value)

• Aw value measuring range from 0,03 to 0,99 aw
• Resolution 0,001 aw
• Calibration 0,10 to 0,80 +/- 0,01 aw
• Long-term stable sensor technologyfor determination of moisture content in food
• Measuring chamber or measuring cell (depending on product volume)
• Lifetime Support

Applications

Portable laboratory instrument for determination of water activity (aw value) of 

food with datalog function. Suitable for measuring materials like butter, fruit mix, 

spices, granulate, mushrooms, xylit, flour, biscuits or sausage as well as all other 

food types requiring a check of the water activity value.

Description

Water activity indicates the amount of unbound water (free water) in a material. It is an important factor in food preservation and quality control - for example for the shelf life of meat or other foods. This quality factor, also known as the aw value, depends on the water vapor pressure in the material, the current temperature and the water vapor pressure in the environment.

The humimeter RH2 food moisture content meter allows quick and easy measurement of water activity. We offer two different sensors:

With the Aw value measuring chamber set 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.

Aw value measuring chamber set:

The Aw vallue measuring 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.

Aw value measuring cell set:

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, that humimeter RH2 In any case, the aw value measuring device 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.

More information on Schaller Messtechnik website:

What is the water activity?

Benefits

• Aw value, relative humidity, absolute humidity, dew point, equilibrium moisture content
• Fast adjustment behavivior
  
• 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 the Video (link below) you can see how the aw value measuring chamber itself is calibrated and adjusted. For this you need the appropriate calibration solution (certified calibration ampoules).

Video Youtube

https://youtu.be/7BDGCT8Rht0

Scope of Delivery

Humimeter RH2 with rubber protection and batteries

Required Accessories 

• AW-value measurement chamber set art. No. 13700
• AW-value measurement cell set art. No. 14500