ICH Q6B · ISO 21807 · HACCP Compliant
Forget fragile sensors and costly maintenance. The GBX eFWM is designed for real laboratory conditions.
ASIC-based sensor technology. Unlike instruments that estimate results in 5 minutes, we measure the true equilibrium. Absolute accuracy guaranteed.
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. Optional 21 CFR Part 11 support for FDA audits (audit trail & electronic signatures).
Very high accuracy and excellent reproducibility, with two precision levels depending on
selected electronics configuration.
ICH Q6B compliance, 21 CFR Part 11 readiness, and precision measurement for pharmaceutical quality control.
Industrial water activity sensors for HACCP compliance, shelf-life prediction, and food safety.
Water activity (aw) is a dimensionless thermodynamic parameter defined as the ratio of the partial vapor pressure of water in a sample to the saturation vapor pressure of pure water at the same temperature:
It reflects the chemical potential of water in a system and therefore quantifies the availability of water for physicochemical and biological processes, rather than the total water content.
From a thermodynamic perspective, water activity is directly linked to Gibbs free energy and governs equilibrium conditions between phases (solid–liquid–vapor).
In practical terms: aw describes how “free” or “mobile” water is in a material.
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).
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.
Regulatory frameworks in food and pharma rely on aw to define safe storage conditions.
A sorption isotherm describes the relationship between water activity (aw) and equilibrium moisture content at a constant temperature.
Typical shape: sigmoidal (Type II) for most food and pharmaceutical solids.
Water activity plays a critical role in drug product stability:
Regulatory guidance (e.g., ICH) emphasizes environmental control where aw is a key parameter.
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:
Shelf life is fundamentally governed by water mobility, not total water content.
Water activity (aw) is a core thermodynamic parameter that governs:
It provides predictive insight that moisture content alone cannot deliver, making it essential for modern quality control and product development in both pharmaceutical and food industries.
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