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.
Accuracy ±0,005 aw (10...30 °C)
±0,1 °C (±0,18 °F)
Chamber-temperature gradient <0,1 °C (<0,18 °F)
Operating range 1...40 °C (34...107 °F)
Sample container dimensions AwT-PS14: Ø46 x 14 mm
AwT-PS40: Ø46 x 40 mm
Sample sizes Variable (14 mm / 40 mm)
Device type Temperature-stabilized water-activity measurement
Measuring range 0.005...1.000 aw
Temperature-control range 0...60 °C (32...140 °F)
Temperature stability ±0,01 °C/min (±0,018 °F/min)
Power consumption 110...230 V / 50...60 Hz
≤2 A
Long-term stability <0.01 aw/year
Humidity sensor Hygromer IN-1
Temperature sensor PT100 1/3 DIN Class B
Calibration / adjustment Aw & Temperature:
HG2-S (probe removed with AwT-CAL)
ROTRONIC humidity standards (via HW4)
Display type 8-line LCD with touch operation
HW4 compatible Yes (v 3.6.0 and higher)
Trend indicator Yes
Aw-quick mode Yes
Software Update Via USB port
Communication interfaces Micro USB
Housing PC / ABS
IP protection rating IP21
Standards ISO 21807
CE / EMC conform EMC 2004/108/EC
IEC EN 61010-1:2010
Maintenance Annual calibration (recommended)
Dimensions 400 x 180 x 180 mm
Weight 4200 g

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

+41 44 838 11 11

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