Use of an ion-exchange sponge to immobilise yeast in high gravity apple based (cider) alcoholic fermentations

Summary An ion-exchange sponge that can have a tailored surface charge has been used for yeast immobilisation in high original gravity (o.g. 1.106) cider fermentation. Continuous circulation of fermentation medium through columns containing weakly basic sponge encouraged yeast growth, decreased batch fermentation time and increased final ethanol concentration, possibly aided by sponge enhanced CO₂ removal from solution.