Formula Foods

Results Fast

Get water activity (a_w) results fast, from New Zealand's premier water activity testing lab, using the world's leading water activity instruments. Testing is performed in accordance with the relevant AOAC method and results are generally available within 4 hours of samples being received.

All water activity analysis is performed on the Decagon AquaLab, the world's fastest and most accurate water activity instrument.

How do I Relate Moisture Content to Water Activity?

The relationship between moisture content and a_w for a product is called a 'moisture sorption isotherm'. You can determine your product's moisture sorption isotherm with our 'Moisture Sorption Isotherm' generation service.

What is Water Activity?

Water Activity (a_w) is the critical factor that measures the shelf life of food products. While temperature, pH and several other factors can influence microbiological activity, water activity is probably the most important factor.

Water activity is a measure of the ‘free’ water in a food sample, as opposed to the ‘ bound’ water. Most bacteria for example, do not grow at water activities below 0.91 and most moulds cease to grow at water activities below 0.80. By measuring a_w it is possible to predict which microorganisms will and will not be potential sources of spoilages.

Learn more about water activity.

Download our handy wallchart showing the critical a_w limits for different micro-organisms.

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