Utilization of Heads by Addition to Alcoholic Fermentations

¹ University of California, Davis

1. The aldehydes contained in the heads obtained from brandy stills were successfully utilized by the action of yeast during alcoholic fermentation. The disappearance of aldehydes during fermentation under suitable conditions amounted to 75 to 95 per cent of the amount added to fermentations of grape must. A maximum permissible level of aldehyde addition was found to be about 0.1%. Successful utilization resulted from additions to must both before and after fermentation had started. Addition of heads after the fermentation had started avoided the extra lag caused by acetaldehyde if added at the start. Aldehydes are presumably reduced to alcohols by the action of yeast. 2. A considerable reduction in esters was also found, amounting fo 25 to 60 per cent, approximately. Curiously, the reduction of esters was observed even in media which could not be successfully fermented, owing to excessive additions of heads. A maximum permissible level of ethyl acetate was found fo be about 1%. 3. A procedure for handling heads under commercial conditions was suggested which offers advantages over existing methods.