Yeast assimilable nitrogen and gluconic acid determination: a valuable tool to improve the winemaking process in extreme weather conditions

The increase of the temperatures, in the recent years, has changed much the meteorological parameters influencing deeply the agricultural activities. This phenomena called “climate change” leads vintages characterized by water scarcity high temperatures as well as vintages characterized by low temperatures and high levels of rainfall jeopardising the correct evolution of the winemaking process and particularly the alcoholic fermentation and how to avoid the stuck fermentation.

Management of alcoholic fermentation in vintages with high temperatures and water scarcity

Grape juices produced from grapes under these conditions will suffer YAN deficiency leading to fermentative difficulties, which can inevitably deteriorate the organoleptic characteristics of the “finished wine”.

YAN analysis has a meaning for the winemaker, only, if he has an in-house method to determine it. This analysis also enables to plan an appropriate nutrition for the yeasts, avoiding dangerous stuck fermentations.

Management of alcoholic fermentation in vintages with low temperatures and high levels of rainfall

In fresh and rainy years, the appearance of Botrytis Cynerea can bring serious problems of mold, which represents one of the main problems of the winegrower. This problem obviously has serious repercussions from an oenological perspective.

Grapes affected by mold, in fact, present high concentrations of gluconic acid derived from the oxidation of glucose by the Botrytis fungi.

This situation leads several problems to the grape juices. Among these, the most dangerous one for the winemaking will be the risk of stuck fermentation due to the depletion of nutrients. Furthermore, the increasing of gluconic acid will make serious difficulty in the grape juice protection through sulphites because the rising of gluconic acid is accompanied by other compounds that bond SO2.

YAN and Gluconic Acid determination to better manage alcoholic fermentation

In the end, besides the usual analyses of sugars, total acidity, pH and acetic acid, yeast assimilable nitrogen (YAN) and gluconic acid are fundamental parameters available for the winemaker to achieve a better management of the alcoholic fermentation.

With CDR WineLab®, in addition to all the other important analyses for the winemaking, the oenologist has the possibility to carry out these two analyses just in a few minutes having, in this way, the possibility to plan the correct nutrition for the yeast and to set up the appropriate protection for the grape juice.

How can yeast assimilable nitrogen and gluconic acid determination affect alcoholic fermentation in the entire winemaking process?

Read "Winemaking in the era of climate change" on Wines&Vines websites

For information in-depth on this important theme click and read:

WINEMAKING IN THE ERA OF CLIMATE CHANGE, the article of Simone Bellassai CDR WineLab® specialist published on Wines&Vines.

Wines&Vines: Winemaking in the Era of Climate Change  Read more at: Copyright © Wines & Vines - Dr. Simone Bellassai