Clarifying agents effect on the nitrogen composition in must and wine during fermentation

The effect of static sedimentation with and without clarifying agents (silica sol and gelatine) upon the nitrogenous fraction of musts and wines was studied. Four vinifications were carried out using a Vitis vinifera cv. Cayetana white grape must. Static sedimentation reduced less than other techniques the assimilable nitrogen (FAN), however the employment of fining agents promoted a net decrease. The changes in the amino acids during fermentation were similar in all the experiments carried out. In general, during the first days there was a fast decrease followed by a slight increment and then stabilisation. This decrease fitted, in most of the cases, with first order kinetics. For most of the amino acids, the percent consumption was higher in the must settled with clarifying agents. The clarifying agent’s addition did not have the same effect on the amino acid concentration in the final wines.