SO2 Wine Calculator

Your details

Sets the recommended molecular SO2 target: 0.8 mg/L for whites, 0.5 mg/L for reds, 1.5 mg/L for dessert wines.
Measure with a calibrated pH meter. pH is the single most important factor determining how much free SO2 you need.
Your measured free SO2 (ppm). Use an Aeration-Oxidation or Ripper titration kit.
mg/L
The active preserving form. Recommended: 0.5 mg/L for reds, 0.8 mg/L for whites, up to 1.5 mg/L for desserts.
mg/L
Volume of wine you are treating. Switch units below.
L
KMS powder gives the most precise additions. Campden tablets are convenient for small batches. A 10% stock solution is easy to measure with a pipette.
Current molecular SO2Protected
0.63mg/L

The active antimicrobial form of SO2 at your current free SO2 and pH

Free SO2 required31.9mg/L
Free SO2 deficit6.9mg/L
KMS addition0.36g
StatusUnder-protected - add SO2 to reach the 0.80 mg/L target
0.63 mg/L
Under-protected<0.3Marginal0.3-0.5Protected0.5-1.5High1.5+

Molecular SO2 is 0.63 mg/L - wine is under-protected.

  • At pH 3.40, you need 31.9 mg/L free SO2 to maintain 0.80 mg/L molecular SO2.
  • Your current level (0.63 mg/L) is below the target. A free SO2 addition of 6.9 mg/L is needed.
  • Recheck free SO2 every 4-8 weeks, and always re-test after racking, filtering, or blending.

Next stepDissolve the calculated KMS or Campden addition in a small amount of wine before stirring it gently through the whole batch.

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