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78 W i n e s & V i n e s D e C e M b e r 2 0 1 4 WineEast hibitors that may have accumulated during the initial stages of primary fermentation. Also, a small amount of DAP is provided in many complex nutrients, which will serve as a final nutrient supply through the end of fermentation (as yeast can no longer take in amino acids, or organic nitrogen sources, by later stages in fermentation due the forma- tion of alcohol). However, suppliers do not often recom- mend DAP additions for high-YAN musts, as this can lead to hydrogen sulfide for- mation. Winemakers should be cautious and avoid making DAP additions when initial YAN measurements are high. This is a good reason why measuring YAN is important. Those winemakers who make routine DAP additions to all fermenta- tions can sometimes do more harm than good, especially in the case of high-YAN fermentations. The table on this page lists several dif- ferent suppliers of nitrogen-based products that contribute nitrogen during primary fermentation, and it is included here to emphasize the variation in nutrient prod- ucts and how supplier recommendations differ. Each of the brands offered by a given supplier represents a line of products to be used for different YAN conditions. Fer- Winemaking Nitrogen Product Lines That Contribute to YAN During Fermentation and Optimal YAN Rates Per Supplier Recommendations COmPANY NiTROGEN PRODuCT LiNES HiGH/mEDium/LOw YAN RATES Beverage Supply Group (BSG)/Lesaffre Startup Startup-Org Superferm Superfood VinfermR Recommended YAN levels to reach by end of fermentation: ≤21° Brix: 200–250 mg N/L 23° Brix: 250–300 mg N/L 25° Brix: 300–350 mg N/L Enartis Vinquiry Nutriferm High: >225 mg N/L Medium: 125–225 mg N/L Low: <125 mg N/L Gusmer Enterprises MicroEssentials Addition rates and timing based on specific fermentation conditions Laffort Bioactiv Dynastart Nutristart Thiazote High: >180 mg N/L Medium: 140–180 mg N/L Low: 40–140 mg N/L Lallemand/Scott Labs Fermaid GoFerm High: >200 mg N/L Medium: 125–200 mg N/L Low: <125 mg N/L This list is an example for winemakers and should not replace product information provided by the supplier. See suppliers' catalogs or websites for complete listings of all products.