Too Much SO2 In My Wine

Smelling Too Much SO2 In The Wine.I’m new and I think I just ruined my first 3 gallons of peach wine. I had everything ready to go to bottle and I went back to the internet to check the amount of potassium metabisulfite to add. I was sure I read 1 teaspoon per gallon prior to bottling, but noticed a really strong SO2 odor when I dumped the small amount of wine left in the 3 gallon carboy while cleaning up. I went back to check the amount again and found anywhere from 1/16th to 1/4 of a teaspoon is what I should have used. I had already corked the bottles at this point and now I don’t know if it can be salvaged. Will it break down if I leave it to age longer?
Name: Chris
State: IL
Hello Chris,
Having too much SO2 in a wine can be a problem. It will not break down in the bottle or anything like that, but what it will do is dissipate into the air and go away. It is just a matter of giving it the SO2 an opportunity to do so.
Depending on the acidity of your wine, about half of the SO2 you added will permanently bond to the wine. This bound sulfite will do nothing to protect the wine. It is just there, and will remain there.
As doses of potassium metabisulfite or Campden tablets are added throughout the wine making process, the amount of bound sulfite builds up. If it builds up too much you can actually taste it in the wine. Fortunately, it takes quite a bit of over-dosing to get to that point. Because the perceptible taste of SO2 can be different from one wine to the next, I do not know for sure if you will be able to test the bound SO2 in your wine or not at the dose of 1 teaspoon of potassium metabisulfite per gallon.
The other half of the SO2 that doesn’t bond to the wine is know as free SO2. This is the half that actually does the protecting of the wine. It slows any oxidative processes that may be wanting to occur. It also stymies any bacteria or mold that may be wanting to grow in the wine.
This is also the half that will give the wine a strong sulfur odor upon decanting when you have too much SO2 in the wine. Since the free SO2 is volatile, it wants to leave as a gas. It just needs the opportunity to do so. This is why doses of potassium metabisulfite are added throughout the wine making process, to replenish the free SO2 that has dissipated as a gas. Here’s more information on this.
With that being said, it should start to become clear to you that you can very easily remedy the problem of having too much SO2 in the wine, but it will requires you to:

  1. Decant the wine back into a bucket fermenter;
  2. Allow the sulfite gases to dissipate;
  3. Re-bottle the wine.

The fermenter needs to sit open to the air for the SO2 gases to escape. You can cover it with a very thin cloth towel to keep stuff from getting into the wine, but nothing more than that. You should let the wine sit like this for a couple of days.
Alternately, you can get a degassing mixer like The Whip to speed up the process. Using an item like this will allow you to degas any wine with too much SO2 in minutes.
This will allow you to rid the wine of the excessive free SO2 — the half you can smell — but it will not do anything to rid the wine of the bound sulfite — the half you won’t be able to taste anyway.
Ironically, it is very possible that all of the free SO2 will be removed with these steps, leaving the wine susceptible to oxidation and contamination. For this reason, I would strongly urge you to test the wine for SO2 before bottling again. This can be done with Titret Test Vials and a Titrettor Hand Tool.
There is one other option for someone that has too much SO2 in their wine. It is much easier to accomplish, but may not be satisfactory to you, especially if you would like to hand these bottles of wine out as gifts. That is to simply pour the wine into a carafe and let it sit for a few hours. You could also invest in an wine aerator. There are many different types on the market that can purchase at a commercial wine store. A good aerator would allow the excess SO2 to dissipate in minutes.
I hope this helps you out Chris. Having too much SO2 in your wine can be a big bummer. Just realize that there are solutions.
Best Wishes,
Ed Kraus
Ed Kraus is a 3rd generation home brewer/winemaker and has been an owner of E. C. Kraus since 1999. He has been helping individuals make better wine and beer for over 25 years.

9 thoughts on “Too Much SO2 In My Wine

  1. Don, the higher the acid level (lower pH) the more free sulfite there will be in relation to the bound. With any wine you will be around 45% too 55%, so it doesn’t vary all that much. At of pH of 3.8 the bound vs. free is about 50%-50%, but realize that other factors can play into this as well, such as the wine’s sweetness and body.

  2. Frustrated…… I have yet to have my question answered…..How much is to much SO2????
    I have 60.8ppm of free SO2. Trying to figure out if this is the reason why my must is not fermenting……. Help me Oby One Canoby, your my only help…..

  3. Ok, thanks so much! I will check both of them out. I forgot to say that I’m only working about 1.7 gallons of must. I was also wondering if you know how I can find out what kind of red grape that I have. I’m not to sure. Its a vine that has been in my moms yard for about 40 or so years that my grandpa planted, who made wine. the vines been getting watered by an underground natural spring. I tried to identify the grape leaf on line and figure its a Zin or a cab, but not sure. Is there some kind of DNA test that I can send for to find out exactly?
    Many Thanks

  4. Very useful information. If I will distillate the wine to alcohol/ethanol will it still has SO2 smell?

  5. Hello, Sir,

    This is Hallo. I would like to ask about one thing, and I’ll be so much thankful if you will be able to help me. Recently, I have added too much SO2 into my wines which are at the stage of aging, and I smell the sulfate in my wine. Based on your suggestion, I had racked my wines into a big bucket, and I little a bit degassed the wines by drill, but until now, I still smell so2.

    After this week, my barrels will arrive, so should I wait to get my barrels and rack them to the barrels? or I should rack them back to the bucket and let them sit until the smell will disappear. I planned to bottle them after 6 or more months later.

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