EFFECTIVENESS OF COMBINED AMMONIACAL NITROGEN AND OXYGEN ADDITIONS FOR COMPLETION OF SLUGGISH AND STUCK WINE FERMENTATIONS

The timing of combined additions of oxygen and assimilable nitrogen wa s optimized. Five mg/l oxygen and 300 mg/l (NH4)(2)HPO4 were added (i) before inoculation, (ii) at the end of the cell growth phase or (iii) at the halfway point of fermentation. There were marked differences b etween the nine combinations. In all cases, adding oxygen at the end o f cell growth and nitrogen at the halfway point of fermentation appear ed to be the most effective combination for completion of the fermenta tion whereas initial additions always had little favorable effect on t his completion. The poor effect of initial oxygenation was partially e xplained by the large fraction of antimycin-sensitive oxygen consumpti on at the beginning of fermentation. The technological usefulness of o ptimized combined additions was shown by testing them during 10 differ ent sluggish fermentations: the mean duration was almost 50% of the me an duration for control fermentations.