Ammonium (NH4)

Ammonium (NH4+) is a naturally occurring source of inorganic nitrogen that is fixed by legumes and can be added as a Diammonium phosphate (DAP) salt to grapevines or must. Ammonium’s utility in grape and wine production continues to be explored as it has various positive and negative impacts. As an essential component of yeast assimilable nitrogen (YAN), ammonium is a versatile tool for supplementing nutrient-deficient soils and avoiding stuck fermentations. Yeasts prefer inorganic ammonium over organic amino acids which can lead to excessively vigorous fermentations, thus making it the “candy” of nutrients (Jiranek et al. 1995). Its overuse also contributes to groundwater contamination, excessive vine vigor, and carcinogen formation (ethyl carbamate). Yeasts prefer While ammonium is an essential additive, our ever-evolving understanding of vine and wine nutrition necessitates a more holistic understanding of YAN, vitamins, minerals, soil organic matter, and oxidation in contribution t