Fermenting a great mead is a little like parenting a sugar-crazed toddler. Sure, honey and water are the base, but without the right support and structure, your yeast can throw a tantrum mid-ferment and leave you with a stuck, sluggish, or downright funky brew. That’s where TOSNA comes in.
TOSNA (Tailored Organic Staggered Nutrient Addition) is a mead maker’s best friend when it comes to ensuring healthy, happy fermentation. This guide breaks down the how, what, and why behind TOSNA—and gives you tools to actually use it. Whether you're a new fermenter or a seasoned homebrewer ready to step up your mead game, let's demystify TOSNA together.
What Is TOSNA?
TOSNA stands for Tailored Organic Staggered Nutrient Addition. It’s a yeast-feeding protocol developed by Scott Labs and championed by modern mead makers to improve fermentation consistency, avoid off-flavors, and create a clean, refined end product. In short, to give us what we want.
Unlike traditional staggered nutrient addition (SNA), which often uses DAP (diammonium phosphate) and Fermaid K, TOSNA 2.0 is organic only, using Fermaid O for nutrients and GoFerm for yeast hydration. Why organic? Because Fermaid O is derived from inactivated yeast cells and provides a full range of amino acids, vitamins, and growth factors—everything your yeast needs to stay happy, healthy, productive, and sugar-crazed.
Why Yeast Needs More Than Just Sugar
Yeast is a living organism, and while it loves sugar, it requires a complete nutrient profile. Sugar fuels the fermentation process, but nutrients support everything else: reproduction, alcohol tolerance, stress resistance, and flavor stability.
Without sufficient nitrogen and micronutrients, yeast can:
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Slow down midway through fermentation or completely stall
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Produce harsh, solvent-like fusel alcohols. Bad for flavor and bad for headaches
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Develop sulfur or rotten-egg off-flavors (Hydrogen Sulfide)
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Fail to fully attenuate (leaving behind residual sweetness or haze)
Think of it like this: sugar is gas, but nutrients are the engine oil. Both are essential for a smooth ride.
How TOSNA 2.0 Works
TOSNA 2.0 provides nutrients in four equal doses using Fermaid O:
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At yeast pitch (Day 0)
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~24 hours later (or at 1/3 sugar depletion)
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~48 hours later (or at 1/2 sugar depletion)
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~72 hours later (or before gravity falls below 1.020)
Each addition gives the yeast a little more fuel without overwhelming it all at once. This prevents sugar stress, minimizes heat spikes, and reduces the risk of sluggish or stuck fermentation.
TOSNA also includes yeast hydration using GoFerm prior to pitching. This helps rehydrate dry yeast in a nutrient-rich environment, increasing cell viability and reducing lag time.
Let's Break It Down with an Example
Let’s say you’re making a 5-gallon traditional mead using 12 lbs of honey. You don’t know your original gravity, but that’s okay—our TOSNA 2.0 Mead Nutrient Calculator handles that for you.
Plug in your:
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Batch size
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Honey weight
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Yeast selection
And the calculator will tell you:
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Estimated OG & Brix
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How much Fermaid O to use (in grams and teaspoons)
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How much GoFerm to use at rehydration
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Volume of rehydration water in oz/mL
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When and how to add each dose of Fermaid O
Bonus: The calculator even shows you the rehydration steps clearly, so there’s no guesswork.
[Launch the TOSNA 2.0 Calculator]
Common Mistakes to Avoid
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Using DAP with high-alcohol meads: Can lead to hot, solvent-like flavors.
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Forgetting a dose or skipping steps: Yeast needs the full schedule.
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Adding nutrients after 1.020: Can cause off-flavors or stress.
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Not rehydrating dry yeast: Leads to lower cell counts and slower ferments.
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Trying to eyeball gram measurements: Use our calculator for teaspoon equivalents!
FAQ
Q: Do I have to use GoFerm?
A: No, but it greatly improves yeast health during rehydration. For higher ABV meads, it’s highly recommended.
Q: What if I don’t know my Original Gravity?
A: Our calculator will estimate it based on honey weight and volume.
Q: Can I use this for melomels or fruit meads?
A: Yes! Just enter the honey weight. If using a large amount of fruit, consider a small nutrient boost beyond Fermaid O.
Q: Is TOSNA only for high ABV meads?
A: No. It benefits any mead that uses a decent quantity of honey and has a potential ABV above ~8%.
Helpful Tools & Resources
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[Liquid Volume Converter]
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[Yeast Hydration Calculator] (Coming soon)
A Final Word (and a Nerdy Acronym)
We at boomchugalug want to thank the mead-making community and Scott Labs for developing the TOSNA protocol. We also want to thank them for choosing an acronym that’s pronounceable and not totally ridiculous.
Unlike our own suggestions:
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NERDS: Nutrient Elevation & Rational Dose Scheduling
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SNARF: Staggered Nutrient Additions for Robust Fermentation
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BOOM: Balanced Organic Optimized Mead-making
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ZAP: Zymurgy-Applied Protocol
No matter what you call it, TOSNA 2.0 is the real deal.
Now go forth, feed those sugar-crazed yeasties, and make some magic in the fermenter!