Water Activity
Water activity (aW) measures the amount of “free water” in green coffee – the portion of water that can evaporate or participate in chemical reactions. Rather than simply measuring water content by weight, aW reflects how “active” the water is, influencing the beans ability to maintain quality and remain stable over time.
Measured on a scale from 0 to 1, higher aW increases the risk of mold growth and oxidation that can compromise flavor. To extend freshness and keep coffee in the safest possible condition, aW should ideally be controlled between 0.55 – 0.60.
In Specialty Coffee, controlling aW helps stabilize bean structure and preserve the full range of characteristic flavor notes. Close monitoring of this indicator is a key step in ensuring that green coffee consistently meets the highest quality standards.