Built on ASIC-based sensor technology, the GBX eFWM water activity meter measures true thermodynamic equilibrium. Unlike competing instruments that estimate results in 5 minutes, our approach guarantees absolute accuracy every time.
Sauce or powder splashed inside? No problem. The measurement chamber is easily accessible for cleaning in 30 seconds.
No filters to replace, no hidden operating costs. A sustainable long-term investment.
Record autonomy. Just a simple battery replacement every two years. No cables, no charger, no expensive filters.
From Field Use to Laboratory Station
Connect the eFWM-Solo sensor to our 7″ or 8″ touchscreen to create a full eFWM laboratory station.
Our magnetic sample cup holder ensures perfect, repeatable sealing. No more fragile mechanical systems.
Standard, easy-to-replace cable and built-in self-diagnostics.
Full traceability. Compliant with ISO 18787:2017 and USP . Optional 21 CFR Part 11 support for FDA and EFSA audits (audit trail & electronic signatures).
Very high accuracy and excellent reproducibility, with two precision levels depending on
selected electronics configuration.
ICH Q6B and USP compliance, 21 CFR Part 11 readiness, FDA/EFSA guideline alignment, and precision measurement for pharmaceutical quality control.
Industrial water activity meters and moisture content analyzers for HACCP compliance, shelf-life prediction, and food safety.
In summary, water activity and moisture content are fundamentally different parameters:
Water activity (aw) and moisture content are different parameters used in quality control and stability analysis.
| Parameter | Water Activity (aw) | Moisture Content |
|---|---|---|
| Nature | Thermodynamic (energy state) | Gravimetric (mass fraction) |
| Unit | Dimensionless (0–1) | % or g/kg |
| Meaning | Water availability | Total water present |
| Predictive power | Microbial growth, stability | Limited predictive value |
| Dependence | Structure, binding, composition | Only quantity of water |
Two materials can have identical moisture content but very different water activities, depending on how water is bound (e.g., crystalline vs amorphous systems).
As a critical thermodynamic parameter, water activity (aw) directly controls microbial growth and product stability in food and pharmaceutical systems.
Water activity is the primary controlling factor for microbial proliferation.
Each class of microorganism has a minimum aw threshold:
| Microorganism | Minimum aw |
|---|---|
| Most bacteria | ~0.90 |
| Yeasts | ~0.85 |
| Molds | ~0.70 |
| Xerophilic molds | down to ~0.60 |
Below aw ≈ 0.60, microbial growth is effectively inhibited.
In essence, a sorption isotherm describes the equilibrium relationship between water activity (aw) and moisture content. When plotted at constant temperature, it reveals three key regions of water binding.
Typical shape: sigmoidal (Type II) for most food and pharmaceutical solids.
Water activity plays a critical role in drug product stability:
Regulatory guidance such as ICH emphasizes environmental control where aw is a key parameter.
In fact, aw is often more relevant than moisture content for predicting real stability behavior.
In food systems, water activity is the single most important parameter for shelf-life determination:
Examples:
In conclusion, water activity (aw) is a core thermodynamic parameter that governs:
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