Nutrient salts. A healthy source of nitrogen & phosphate to promote yeast growth and vigorous fermentation. Used as a Yeast Nutrient in Brewing, Cider, Mead, Winemaking and Hard Seltzer. Wort is generally rich in nitrogen, but a little supplementation can help high-gravity beers complete fermentation. Use 5 grams per 20 litres of must or wort