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Home  /  Water Activity  /  AW-therm

Benchtop AW-meter

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.


  • 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


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)
Calibration / adjustment Aw & Temperature: HG2-S (probe removed with AwT-CAL)
Aw: ROTRONIC humidity standards (via HW4)
Dimensions 400 x 180 x 180 mm

Why measure

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