Diammonium Phosphate - Most amateur musts are lacking in the nitrogen necessary for yeast growth. If no other source is available amino-acids from dead yeast will be de-aminated with the result that fusel oils will be produced as a by-product. The phosphate radical is also of great importance for a healthy vigorous fermentation as it is required in some of the reactions as an energy transferer. About 5 grams per gallon are required, together with other additives.