calculator
Backsweetening calculator.
Enter the batch volume and both gravities to see how much honey to add.
Why the warning matters
Sweet mead in a sealed bottle restarts fermenting if viable yeast meets fermentable sugar — pressure builds until bottles overcarbonate or burst. Stabilize first: potassium metabisulfite plus potassium sorbate after fermentation is complete and the mead has cleared, or sterile filtration, or pasteurization. Sorbate stops yeast from reproducing but won't halt an active fermentation, so confirm the gravity is stable over 2–3 days before stabilizing, and re-check it for a week after sweetening. Cold storage only postpones the problem. For sweet sparkling mead, keg and force-carbonate instead of bottle conditioning.
The math uses the same honey model as the batch planner (1 kg honey ≈ 0.319 gravity points per litre, and it adds ~0.7 L of volume per kg), so the suggestion accounts for its own dilution. It's an estimate — add in stages and taste.