A wine’s distinguishing features arise from the must it is made from. The latter’s analytical monitoring during the pre-fermentation phase is an essential requisite to obtain a high quality wine. Total acidity, pH, sugar content, volatile acidity are just some of the tests that allow an accurate analytical monitoring of wine must, both before and during the alcoholic fermentation phase. These analyses might not be sufficient to achieve a quality wine if the grapes have been harvested in specific weather conditions, namely hot and dry, or cool and rainy. In such years it is of paramount importance to quickly and easily assay further parameters such as gluconic acid, yeast assimilable nitrogen and malic acid. Let us see when.