A mead nutrient schedule calculator determines how much Fermaid-O to add at each stage of fermentation using the TOSNA protocol. Staggered nutrient additions are critical for preventing H₂S, avoiding stuck fermentation, and producing clean, complex mead.
Mead Batch Details
Traditional mead: 1.080–1.130
Dry mead: ~1.000 | Semi-sweet: 1.010–1.020
How to Use the Mead Nutrient Schedule Calculator
The TOSNA protocol revolutionized modern meadmaking by replacing old nutrient practices with a clean, organic, staggered approach. This mead nutrient schedule calculator generates your complete Fermaid-O addition plan based on your batch parameters.
Step 1: Enter batch details
Input your batch size in gallons and original gravity. For a 1-gallon traditional mead with 2.5 lbs of honey, expect OG around 1.075-1.090. A show mead with 3 lbs/gallon starts around 1.100-1.120.
Step 2: Follow the nutrient schedule
The calculator provides 4 addition timestamps: 24 hours, 48 hours, 72 hours after pitching, and at the 1/3 sugar depletion gravity (track with a hydrometer). Rehydrate Fermaid-O in a small amount of must before adding to avoid foaming over.
Step 3: Degas during active fermentation
Use a whisk, degassing wand, or stir plate to degas your mead 1-2 times daily during active fermentation. CO2 dissolved in the must stresses yeast and can prevent nutrient uptake. Degassing is as important as proper nutrients for a clean, fast mead.
Frequently Asked Questions
Is this mead nutrient calculator free?
Yes, completely free with no account required. All calculations run locally in your browser.
Is my data safe?
Absolutely. No data is sent to any server.
What is the TOSNA protocol?
TOSNA (Tailored Organic Staggered Nutrient Additions) is a mead nutrient protocol developed by Sergio Moutela. It uses only Fermaid-O (organic nitrogen source) in 4 staggered additions: at 24 hours, 48 hours, 72 hours, and at 1/3 sugar depletion (1/3 of the way from OG to FG). This prevents H2S production and supports healthy yeast through the nutrient-poor honey environment.
Why does mead need nutrients?
Honey is notoriously nutrient-poor for yeast — it provides sugar but lacks the nitrogen, vitamins, and minerals yeast needs to thrive. Without added nutrients, mead fermentations often produce hydrogen sulfide (rotten egg smell), stall, and take months to finish. Proper nutrients lead to clean, fast fermentation.
What is Fermaid-O vs Fermaid-K?
Fermaid-O is an organic nitrogen source (yeast hulls) that provides assimilable nitrogen without inorganic ammonium. It's the preferred nutrient for TOSNA because it avoids the off-flavors that can come from Fermaid-K's DAP (diammonium phosphate) at high additions. Fermaid-K can be used in smaller amounts alongside Fermaid-O for very high-gravity meads.
How do I calculate 1/3 sugar depletion?
1/3 sugar depletion is the point where 1/3 of your OG points above 1.000 have been consumed. For example: OG 1.100, FG target 1.000, so total attenuation = 100 points. 1/3 depletion = 33 points consumed, so gravity reading is 1.067. Check your gravity with a hydrometer and add the final nutrient dose when you reach this point.