After roasting, the decisive phase begins for coffee roasters: the residual moisture in the bean determines whether the aroma, taste and shelf life can develop optimally. It also influences the filling weight, flow behaviour and storability of the coffee – the key quality characteristics in further processing and packaging.
Why residual moisture is so crucial
While green coffee beans still have a moisture content of between 10% and 13%, this is deliberately reduced during roasting. The heat of around 200–230 °C causes water to evaporate, cell structures to change and the typical roasted aroma to develop.
However, if the bean is too moist, it can ferment further, lose aroma and become unstable. If it is too dry, the coffee tastes flat and loses intensity.
This is why precise control of the residual moisture immediately after the roasting process plays a key role – both for consistent taste and for economic process reliability in production.
Inline moisture measurement with capacitive technology
With moisture measurement systems from ACO Automation Components, residual moisture can be measured directly in the product stream – in real time and without sample loss.
The system is based on the capacitive measurement method: changes in water content affect the dielectric properties of the material. These are detected by the sensors and converted into exact moisture values.
This provides roasters with reproducible measurements that can be used immediately for process control – without interrupting the production flow.
Advantages of inline measurement in the coffee industry
- Consistent product quality: Consistent moisture ensures stable taste and aroma.
- Less waste: Fluctuations are detected and corrected at an early stage.
- More efficient further processing: Optimally conditioned beans improve flow behaviour and filling processes.
- Real-time monitoring: Quality and production managers have the moisture content in view at all times.
Conclusion
Coffee is a natural product – but consistent quality can only be achieved through control. With ACO’s capacitive inline moisture measurement, roasters can keep track of this crucial parameter at all times and lay the foundation for a product that impresses customers every day.
Because in the end, it’s not luck in the roasting drum that counts –
it’s the control afterwards.
