Although wort is a good growth medium for yeast, additional Wyeast Nutrient will reduce lag time, improve yeast viability and provide consistent attenuation rates. Low assimilable nitrogen concentrations (FAN) of grape must or wort have long been known as a cause of sluggish or stuck fermentations. Wyeast yeast nutrient, a blend of vitamin B's, minerals, inorganic nitrogen (DAP), organic nitrogen (amino acids), zinc, phosphates and other trace elements will benefit yeast growth and carbohydrate uptake for a more rapid, complete fermentation. Use 1/4 tsp per pint for beer propagation, 1 tsp per 5 gallons for wine or beer fermentation or 1.5 oz per 10 barrels for beer fermentation.