A sensor system (100) or a sensing method minimizes the loss of aroma chemicals or other analytes in a sample gas while controlling the temperature and humidity of the sample gas. The system (100) may employ a humidifier (120) that adds water vapor to sample gas to provide a known water content, e.g., a saturated humidity at a known temperature. A sensing unit (130) may accurately measure the composition of the sample gas having a known water content, e.g., at a higher known temperature.