Fermaid O
22.5g
DAP
0g
Additions
4
22.5g
0g
5.6g
0g
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Inputs
Result
TOSNA = 4.5g/gal × 5 gal × 1.0 (traditional) = 22.5g Fermaid O. Split into 4 additions = 22.5 / 4 = 5.6g per addition. No DAP in TOSNA.
Inputs
Result
TBE: FO = 2.5g/gal × 3 gal × 0.8 (melomel) = 6g. DAP = 1.5g/gal × 3 × 0.8 = 3.6g. Per addition: 6/4 = 1.5g FO, 3.6/4 = 0.9g DAP.
Using the TOSNA protocol, you need about 4.5 grams of Fermaid O per gallon of traditional mead, split across 4 staggered additions. For a 5-gallon batch, that is 22.5 grams total or about 5.6 grams per addition. Melomel (fruit mead) uses 20% less because fruit provides some nutrients. Sack meads (high gravity) use 30% more due to extra yeast stress.
| Protocol | Fermaid O / gal | DAP / gal | Best For |
|---|---|---|---|
| TOSNA | 4.5g | 0g | Clean flavor, organic-only |
| TBE | 2.5g | 1.5g | High-gravity meads |
| DAP Only | 0g | 3g | Budget option |
SNA divides the total nutrient dose into 4 equal additions given at yeast pitch, 24 hours, 48 hours, and the 1/3 sugar break (when gravity drops by 1/3). This prevents nutrient overdose early on and provides sustained support as yeast populations grow. Degas the mead before each addition by stirring to release CO2, which helps the yeast metabolize nutrients.
TOSNA (Tailored Organic Staggered Nutrient Addition) uses only Fermaid O, an organic nutrient. It produces the cleanest flavors with no off-aromas. TBE (balanced blend) combines Fermaid O with DAP for high-gravity meads. DAP-only is the cheapest option but can produce fusel alcohols and off-flavors if overused, especially above 9% ABV.
Honey is nutrient-poor compared to grape must or fruit juice. Without added nutrients, yeast becomes stressed and produces fusel alcohols (hot, harsh flavors), hydrogen sulfide (rotten egg smell), and may stall or stop fermenting entirely. Proper SNA prevents these issues and produces clean, smooth mead that needs less aging.
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Last Updated: Mar 19, 2026
This calculator is provided for informational and educational purposes only. Results are estimates and should not be considered professional financial, medical, legal, or other advice. Always consult a qualified professional before making important decisions. UseCalcPro is not responsible for any actions taken based on calculator results.