Laboratory Analyzer for water activity measurement

AwTherm - Water Activity Meter

Stable temperature yields precise measurements.

Temperature-stabilized measurement
With AwTherm, ROTRONIC offers a professional, high-end laboratory unit for temperature-stabilized measurement of water activity in the foodstuffs, cosmetics, or pharmaceutical industries.
The wide control range permits measurements to be integrated directly in the tempered manufacturing or storage process. Water-activity measurement reacts very sensitively to variances in temperature. Stabilizing the temperature prevents imprecise results due to external temperature influences.

Exchangeable measuring head
A further advantage of AwTherm is that the measuring head is removable, which means that the probe can be temperature-calibrated or adjusted to give high precision.

The AwTherm shows its paces in island-operation mode, with its simple handling and clarity. No laboratory should be without the device in conjunction with the ROTRONIC HW4 software

Why measure water activity?
The free water in a product influences its microbiological, chemical and enzymatic stability. If there is too much free water present, the products spoil; too little water can be detrimental to the product characteristics.

Water activity Contaminants
aw = 0.91..0.95 Many bacteria
aw = 0.88 Many yeasts
aw = 0.80 Many mildews
aw = 0.75 Halophile bacteria
aw = 0.70 Osmiophile yeasts
aw = 0.65 Xerophile mildew

Measuring water activity provides useful information about characteristics such as cohesion, storage lifetime, clotting or pourability of powders, tablets, etc., or the adhesive properties of coatings.


  • Highest precision through exact stabilization of temperature
  • Wide temperature-control range
  • Excellent reproducibility
  • Excellent long-term stability
  • Variable size of sample container
  • Reference probe exchangeable for calibration or cleaning
  • Quickest measurements with the AwQuick function
  • Simple operation via Touch Interface
  • Conforms to ISO 21807 / EMC 2008/108/EC / IEC EN 61010-1:2010

ROTRONIC provides a high-end laboratory device, the HygroLab C1, for water activity measurements from as many as four separate probes. Use multiple stationary probes and insertion probes for measuring water activity in cheese, meat, tobacco, building materials, animal feed, pharmaceuticals products and much more.
More Information
Humidity sensor Hygromer IN-1
Temperature sensor PT100 1/3 DIN Class B
Long-term stability <0.01 aw/year
Measuring range 0.005...1.000 aw
Calibration / adjustment Aw & Temperature:
HG2-S (probe removed with AwT-CAL)
ROTRONIC humidity standards (via HW4)
Power consumption 110...230 V / 50...60 Hz
≤2 A
Dimensions 400 x 180 x 180 mm
Operating range 1...40 °C (34...107 °F)
Display type 8-line LCD with touch operation
Trend indicator Yes
Software Update Via USB port
IP protection rating IP21
AwQuick Mode Yes
Communication interfaces Micro USB
Weight 4200 g
Housing PC / ABS
HW4 compatible Yes (v 3.6.0 and higher)
CE / EMC conform EMC 2004/108/EC
IEC EN 61010-1:2010
Standards ISO 21807
Maintenance Annual calibration (recommended)
Device type Temperature-stabilized water-activity measurement
Accuracy ±0,005 aw (10...30 °C)
±0,1 °C (±0,18 °F)
Sample sizes Variable (14 mm / 40 mm)
Sample container dimensions AwT-PS14: Ø46 x 14 mm
AwT-PS40: Ø46 x 40 mm
Temperature-control range 0...60 °C (32...140 °F)
Temperature stability ±0,01 °C/min (±0,018 °F/min)
Chamber-temperature gradient <0,1 °C (<0,18 °F)

Want to learn more about our products?
We will be pleased to personally advise you.

+44 1293 571000


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