Ask Wine Wizard

Over-Sulfited Wine


Jared Hermany — Allentown, Pennsylvania asks,

I screwed up my wine pretty badly by adding 3 tsp of potassium metabisulfite to 3 gallons (11 L) of Concord and the same to my Niagara. I had my wine tested by a local lab and they alerted me to the fact that my free SO2 was excessively high — 15 and 18 times what it should be. Do you have any recommendations as to how I can fix this? It has been suggested that I agitate it to mix air into the wine. Is the wine salvageable? In the unrealistic event I would be able to get these sulfites down to acceptable levels, do you think that this type of constant agitation would alter the flavor of the wine?


Oh boy, oh boy, oh boy. Sounds like you have a lot of sulfur dioxide in that wine! Assuming standard FSO2 for bottled wine being around 25 ppm, am I correct in interpreting 15-18 times higher “than what it should be” to be around 375 ppm FSO2? If that’s the case, I think you are way too high to “wait it out” or to try to agitate the wine in hopes of oxidizing it. I really think your only hope, and it’s a slim one since the remedy might be worse than the disease, is to use hydrogen peroxide to try to remove it.

Hydrogen peroxide (yes, the 3% stuff you can buy at the pharmacy) is a very strong oxidizer. In fact, at high concentrations (not available at the pharmacy) it’s such an “instant” oxidizer that it is used as a propellant in rocketry! Even if you’re using the “diluted stuff” it’s still important to treat it with respect and to mix it carefully into wine. Because sulfur dioxide is so easily-oxidizable, hydrogen peroxide naturally “finds” the easily-oxidized SO2 and the two hopefully cancel each other out. You have to measure your volumes extremely carefully, however, because if there’s any un-oxidized hydrogen peroxide, it will go for all the other goodies in your wine, probably darkening the color and perhaps permanently changing flavors. I offer the following procedure as a last-ditch effort to save this batch of wine.

Before you start, it’s critical you know what your beginning SO2 concentration is. You do not want to add more hydrogen peroxide than you absolutely have to. If you’re at all doubtful about your own lab skills or worry about your reagents being a little out of date, it’s best to send a sample to a professional wine lab. After you get your result in ppm FSO2, calculate how much hydrogen peroxide you will need. To remove 10 ppm SO2 in 1 gallon (3.8 L) of wine, you will need to add 3.5 mL hydrogen peroxide. Use a brand new bottle, making sure to check the expiration date. Measure very carefully using a finely-graduated pipette (10 mL or 5 mL) to be sure you’re not adding too much. Stir gently into your wine. The reaction should take place relatively quickly but it’s best to wait 24 hours before sampling your wine again to re-check the new level of sulfur dioxide.

For more on this topic check out “Wine Kit First Aid” by Tim Vander-grift in the December 2002-January 2003 issue of WineMaker. In the future, I’d also advise that you take advantage of the sulfite calculator on WineMaker ’s website at www.winemakermag.com/sulfitecalculator.

Response by Alison Crowe.