During alcoholic fermentation, nitrogen is one of the essential nutrients for yeast, as it plays a key role in the transport of sugars and the biosynthesis of wine aroma compounds (thiols, esters, higher alcohols).

The main problem of a lack of easily assimilable nitrogen (AFN) in winemaking is sluggish fermentations or stuck fermentations that favor the growth of contaminating microorganisms and cause economic losses. However, correcting this nitrogen deficiency is not always sufficient to restore proper fermentation development. This suggests the existence of other nutritional deficiencies.

The objective of this work was to study the impact of the timing and nature of nutrient addition (mineral nitrogen, 100% yeast-derived, or a mixture of mineral and yeast-derived nitrogen) on alcoholic fermentation.

First, 16 commercial strains were inoculated in Sauvignon white grape must deficient in NFA (110 mgN/L) and with a sugar concentration of 240 g/L (expected alcoholic strength of 14.3 %vol.). Subsequently, the fermentation kinetics of each strain was classified into 3 groups: arrested, slow, or complete alcoholic fermentations. New trials were performed on the same grape must with additions of NFA in the form of ammonium (mineral) or yeast-derived products (100% organic or mixed) to obtain 200 mgN/L. Nutrient additions were made at the beginning of alcoholic fermentation (single addition) or in two stages (50% at the beginning + 50% in the middle of alcoholic fermentation). Our results show that the addition of mixed nutrients provides more benefits to fermentation than the use of mineral nitrogen alone. Fractional addition also appears to have a better impact than single addition. This study evidences the need to approach yeast nutrition from a holistic perspective (nitrogen and lipid addition, timing of addition).