So2 too high

Rick,

Titrets often read false high. Are you sure you are reading the end point correctly?

Assuming the wine really does have 95 mg/l SO2 in it, you could try splash racking. This is harmful - you would have to do it multiple times to remove that much SO2 and you will almost certainly strip aromatics. There is an alternative: hydrogen peroxide. See

section 15, for more.

HTH, Ben

Actually I'm not sure how it got that high but I'm leaning toward that I may have read it upside down last spring when I racked last late winter which would explain the situation but yes it's at about 95 ppm. I'll check out the hydrogen peroxide solution and correct it this weekend. Also the wine does taste promising but I can pick up the so2 flavor and from what I've noticed in the past from the few I have under my belt is that when wine is bulk aging or bottled so2 drops off at a very slow rate which would take years to hit a point where it's drinkable.

Thanks, Rick

Rick,

I'm aware of two ways to treat over-sulfited wine. One is to rack it and splash it as you've mentioned and the other is to treat it with a small amount of 5% Hydrogen peroxide. At 95 ppm's it is definitely a little higher than you might want but not so high that the wine is spoiled.

From what I've read, 95-100 ppm's is just around the threshold where the taste is detectable however, over time the level with slowly decrease. It it were mine I would only rack/splash it and leave it in a carboy for at least 3-4 months then taste it and check the sulfite level at that time before deciding on next steps.

Glen Duff

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Rick wrote:

Rick,

It's pretty early in the morning here and I was thinking (or not thinking) of the hydrogen sulfide problem when I mentioned hydrogen peroxide (H202) treatment. Hydrogen peroxide does not reduce SO2 levels.

Sorry about that, I'm now wide awake!

Cheers,

Glen Duff

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Rick wrote:

It would. I'd re-test and check and use H2O2 is necessary.

True. If you can really smell the SO2, it is most likely to be high. Ben

What is the reaction? SO2+H2O2=H2SO4???? What??

LOL! Ya had me going for a minute there!

Glen,

Not sure why you're saying this - H2O2 *can* be used to reduce SO2 levels. Why are you saying otherwise?

Ben

That's my understsanding also. I'm not sure I would try for more that

15 PPM reduction, but that is from memeory. (That's why I get the books...)

Joe

Well... It may have been really early... ;-) Hydrogen Peroxide reduces the S02 in your wine by a predictable amount.

For every 10 ppm of free SO2 you want to remove, add 1 ml of 3% (commonly available in the pharmacy) Hydrogen Peroxide. Use only FRESH

3% for this remedy. Be aware that this method works for removal of up to 100 ppm (remember to leave some SO2 in the wine). If you go farther, your wine will oxidize and lose flavor. It also adds a harshness when done in larger amounts that I cannot explain. Maybe we have a chemist that can shed some light?

In experiments I have performed, this works very well, and is predictable. Like others have posted, I would reduce only by the amount you absolutely need. If you taste it, it probably needs to be reduced.

Paul

I'm not a chemist, but sulfite ion and hydrogen peroxide react forming sulfate and water (sulfuric acid). This reaction can be written as: SO3-- + H2O2 ==========> SO4-- + H2O Perhaps the sulfuric acid produces the harshness. Lum Del Mar, California, USA

I was under the impression the sulfites made SO2, so the reaction is SO2

• H2O= H2SO4.

WHOOPS! My mistake! That's what I get for posting sober....

SO2 + H2O= H2SO4.

That equation isn't balanced. Also, it ignores the equilibrium effects. In simplified form it would be: SO2 + H2O H2SO3 (sulfurous acid)

In wine, the active agent is SO2 itself, in molecular form. The equilibrium of the above equation is driven to the left by lowering the pH. That explains why more sulfite is required in high pH wines to achieve the same level of molecular SO2.

The SO2 reacts with oxygen like this:

2SO2 + O2 ==> 2SO3 (sulfur trioxide)

Then the sulfur trioxide reacts with water to form sulfuric acid: SO3 + H2O ==> H2SO4

This is all a bit oversimplified, but that's the general idea.

Tom S

OK. So we can reduce the amount of "free" S02 via a treatment with peroxide, but we end up with sulfuric acid. This must be the harshness I taste. I have a couple of related questions.

1) During the winemaking process, the free S02 is reduced. This is why we add it at first racking. So where does it go? I have heard it becomes "bound" and so is not "free", but does it impart a taste anyway? For example, if I had started with 50ppm of S02 at crush, and didnt add any until bottle time, my measurable S02 would be very low. Does this mean that sulfur is still in the wine, albeit bound and inert? Can I taste that? Does adding sulfer at the first rack make more of this bound S02 that can eventually be tasted? 2) In red wines, do we really need to add much S02? Tannins in the seeds, stems and skin is a natural preservative, is it not? If I have a fairly high acid, tannic wine, can I add less S02 and feel confident things will not spoil? 3) Can I reduce the S02 in my wine by racking and splashing down the side of my containers? How many ppm would I reduce by if I racked this way? Is there a rough guestimate or rule of thumb that someone knows?

Thanks,

Paul