Calculate the yeast nutrient (YAN) your ferment needs based on its gravity and base ingredient — critical for country and fruit wine, where most fruit and flower musts are very low in natural nitrogen. Outputs a TOSNA 2.0 staggered Fermaid-O schedule, or a single Fermaid-K / DAP addition.
Calculate yeast nutrient additions to meet YAN (Yeast Assimilable Nitrogen) requirements. Essential for country and fruit wine — most fruit and flower musts are very low in natural YAN.
Natural YAN from your fruit source
Target YAN
250 ppm
Natural YAN from fruit
18 ppm
YAN deficit
232 ppm
TOSNA 2.0 — Fermaid-O only schedule
A fixed dose for the batch size (1.2 g/L) — not derived from the YAN deficit above, because honey carries almost no nitrogen.
Track this in your batch log
MakeWine is a free winemaking app — log additions, lab readings and fermentations, and get a deterministic assistant. No card required.
Most fruit and flower musts provide far less than the 250–350 ppm YAN a healthy ferment needs (honey, for example, has only ~18 ppm). Enter your OG and volume and the calculator outputs the deficit plus a TOSNA staggered schedule.
TOSNA (Tailored Organic Staggered Nutrient Additions) splits organic Fermaid-O into equal doses at pitch and 24/48/72 hours, which is gentler and cleaner than a single inorganic addition. The calculator divides the total into four doses for you.
Calculations are estimates based on standard winemaking formulas (Henderson–Hasselbalch for SO₂, Duncan & Acton for wine ABV, standard addition rates). Always verify critical additions with a reference or lab analysis. The decision and responsibility for any addition rest with you.