In this study two aspects of the influence of water on flavour retention were evaluated. The first part of the study was focused on the influence of dehydration and subsequent reconstitution of mandarin juices, which was examined by headspace Proton Transfer Reaction Mass Spectrometry. The different treatments were discriminated by their mass spectra with help of Principal Component Analysis. The second part of the study concerned intranasal volatile flavour retention during food consumption. Volatile flavour concentrations were measured at four intranasal locations in nine subjects during consumption of custard desserts. Differences between the locations indicated various degrees of retention of volatile flavour compounds by the watery mucous in the nasal tract.