Too Much Sulfite

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mainshipfred

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I have a few wines that I must have double or somehow over sulfited. The worst is a 3 gallon carboy of a 2018 Merlot at 90 ppm and a 25 liter barrel of Cab Sauv at 81 ppm. I'm not overly worried about the Cab since it's a 2019 spring batch in a barrel but any ideas on lowering the level level of the Merlot? I splash racked it from the carboy and back twice and the level didn't change. The reason I want to lower it is because I think the sulfite levels are affecting the taste and I want to blend with it and all of the wines I want to blend with are in the 40-50 ppm range. Plus I need the carboy.
 

Johnd

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I have a few wines that I must have double or somehow over sulfited. The worst is a 3 gallon carboy of a 2018 Merlot at 90 ppm and a 25 liter barrel of Cab Sauv at 81 ppm. I'm not overly worried about the Cab since it's a 2019 spring batch in a barrel but any ideas on lowering the level level of the Merlot? I splash racked it from the carboy and back twice and the level didn't change. The reason I want to lower it is because I think the sulfite levels are affecting the taste and I want to blend with it and all of the wines I want to blend with are in the 40-50 ppm range. Plus I need the carboy.
Hydrogen peroxide will strip it out pronto. Don’t know the dosage requirements, but I’d try a 1 L sample with a few drops, test it, and go from there.
 

mainshipfred

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Hydrogen peroxide will strip it out pronto. Don’t know the dosage requirements, but I’d try a 1 L sample with a few drops, test it, and go from there.
Thanks, didn't know that. Just researched it and it appears .38 mg will reduce the 3 gallons 25 ppm. I may start with that and step it down slowly.
 

stickman

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.38 sounds low, remember that the typical drug store hydrogen peroxide is only a 3% solution.
 

stickman

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I calculate you need 6ml of the 3% solution to drop the so2 by 30ppm for a 3gal carboy.
 

stickman

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Hydrogen peroxide comes in various concentrations, for example 35%, but due to its hazardous nature it is typically only available industrially or through chemical supply distributors. I was just pointing out that calculations might be theoretical and based on 100% hydrogen peroxide, and that a correction would be needed for use of a solution concentration less than that.
 

mainshipfred

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Below is the article I found online. Looks like I didn't look at it carefully enough. They are referring to a 35% solution. When I came up with my .38 ml for my 3 gallons I just interpolated the 58 ml per 1700 liters. So I'm assuming I'll need closer to 4 ml (or 6 as you indicated) of 3% solution if I'm understanding correctly.

TN06—Removal from and addition of sulfur dioxide to must, juice and wine Scope A means of calculating the appropriate addition of hydrogen peroxide required to reduce the concentration of sulfur dioxide (SO2) by a desired amount is described. Brief notes on techniques for the addition of SO2 to musts and wine are also given. 1. Removal of SO2 from wine A. Hydrogen peroxide The removal of sulfur dioxide from wine using hydrogen peroxide (H2O2) is an effective, and if performed carefully, safe procedure. The H2O2 reacts with the free SO2 in the wine, oxidising it to sulfate. After such removal, further free SO2 may be generated from the remaining bound fraction. The H2O2 should be added in a dilute form (recommend less than 1% w/v), slowly, with adequate mixing (e.g. tank recirculation) to avoid localised oxidation. The wine should then be allowed to equilibrate for at least several hours before confirmatory analysis of the concentration of remaining free and bound sulfur dioxide in the wine is done to confirm the success of the addition. The Australian Food Standards Code part P4 lists H2O2 amongst several legal additives. A copy of this document is available from the Institute on request. It sets a maximum concentration of H2O2 permitted in wine of 1 mg/L, and a maximum concentration of soluble sulfates at 20ºC of 2 g/L. The maximum concentration of total sulfur dioxide is, at the time of preparation of this document, 300 mg/L (“for wines containing greater than 35 g/L of sugars”; the limit is 250 mg/L for wines with less than this concentration of sugars); this is, along with all aspects of the Standard, subject to review from time to time. The legality of H2O2 use varies from country to country; and at the time of preparation of this document, it is not a permitted additive in the European Union, for example. The following guidelines detail how to calculate the quantity of H2O2 to add in order to remove a given concentration of SO2. The Institute is happy to give further specific advice regarding the practical aspects of the operation if required. Winemakers should be aware of the potential risks of a loss of wine quality associated with hydrogen peroxide additions if care is not exercised. H2O2 is a strong, non-specific oxidising agent, and under the conditions of use in wine it may have a limited effect on various other wine components. 1. Estimate concentration of free SO2 to be removed. Allow a 10% safety margin. For example, if a wine has a free SO2 of 50 mg/L and it is desired to reduce this to 25 mg/L, then 25 mg/L must be removed. However, it is wise to allow a 10% safety margin, so calculate H2O2 addition on the basis of removing 22 mg/L. 2. Calculate corresponding amount of SO2 Multiply concentration of free SO2 to be removed by the volume of wine (L) in question. It is advisable at this stage to divide the result by 1000 to express the answer in terms of grams (rather than milligrams). 3. Calculate corresponding amount of H2O2 Molecular weight of SO2 = 64 Molecular weight of H2O2 = 34 Therefore, corresponding amount of H2O2 = 34/64 4. Express amount of H2O2 calculated as a measurable volume The amount of H2O2 calculated above must be expressed in terms of volume, according to the strength of the solution used. Commercial H2O2 is typically 30–35% w/v. Technical Services Group Technical Note Date of Issue: 27 March, 2007 dioxide to must, juice and wine Authorised by: Wine Research Page 2 of 2 in Technical Note TN06—Removal from and addition of sulfur 2 5. Caution  Never decrease the calculated free SO2 to less than 5 mg/L.  Always allow for a margin of safety.  SO2 will re-equilibrate in solution after a fairly short time. It is quite common to have to add H2O2 in several stages in order to achieve the final SO2 concentration desired. 6. Numerical example:Removal of 25 mg/L SO2 from 1700 L wine. Calculate the amount of SO2 to be removed: 25 mg x 90% x 1700 L = 38250 mg (= 38.3 g) Calculate corresponding amount of H2O2: 38.3 g x 34/64 = 20.32 g Express amount of H2O2 as a volume: Assume 35% w/v (i.e. 35 g/100 mL) H2O2 used = 20.32 g x 100 mL/35 g = 58 mL
 

stickman

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I have only done this on a small scale, I was testing the concept before potentially treating a larger quantity, in the end, I decided to blend the high so2 batch with some wine I had that just finished ML. One of the critical issues is that the peroxide has to be added drop wise, slowly, with constant mixing, otherwise localized high concentrations of peroxide will remove all so2 (from the local area) and oxidize the wine.
 

cmason1957

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I have only done this on a small scale, I was testing the concept before potentially treating a larger quantity, in the end, I decided to blend the high so2 batch with some wine I had that just finished ML. One of the critical issues is that the peroxide has to be added drop wise, slowly, with constant mixing, otherwise localized high concentrations of peroxide will remove all so2 (from the local area) and oxidize the wine.

I wondered if blending with something else that was almost none wasn't going to be the best way to go. As it so often is, if you have the thing to blend into.
 

mainshipfred

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I am going to take it insteps since I'm not sure about the bound issue but the article, as well as another I read said it could release some of the bound SO2 through the process. I just added 6 ml of the 3% solution and will take a reading in the morning. The actual original ppm was 94.

@cmason1957 all my remaining 18s are around 50ppm and the 19s were just sulfited to 50-60 ppm.
 

NorCal

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I'd leave it alone, it will drop on it's own over time. I regularly hit my high pH with that much SO2 up-front.

Oops, too late, hopefully it turns out well, with no side effects.
 

Johnd

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As with anything you try to adjust, just go slow. Start with way less than you think you need, then measure, and repeat until you get to your target. You don’t want to completely strip it down.
 

mainshipfred

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I'd leave it alone, it will drop on it's own over time. I regularly hit my high pH with that much SO2 up-front.

Oops, too late, hopefully it turns out well, with no side effects.
I don't normally go that high but I do initially sulfite higher then the recommended amounts.
 

mainshipfred

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How sure are you that the sulfite was affecting the taste? Because 90ppm really shouldn’t be noticeable Did you think the sulfite was affecting the taste before you realized the ppm level was higher than expected?
@Boatboy24 and I did a tasting of my final four 2018s that I was trying to bottle. The only one that had an indescribable taste was the Merlot.
 

mainshipfred

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I took the readings this morning and after sitting over night after adding the 6 ml it was at 78 ppm, a drop of 16 ppm. I added another 6 ml, stirred and waited about 30 minutes and it dropped to 50 ppm or a drop of 28 ppm. The whole thing about the potential of releasing some of the bound SO2 perhaps may be a longer time frame. I'm going to wait until this afternoon and test it again. Real curious what the reading will be and if it does release some of the bound.
 

stickman

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Be careful, don't get carried away with the additions, note that in your article above they recommend using 1% hydrogen peroxide solution with good mixing. "The H2O2 should be added in a dilute form (recommend less than 1% w/v), slowly, with adequate mixing (e.g. tank recirculation) to avoid localised oxidation." The idea here is to selectively oxidize the free so2 and not the wine.

Also remember that any dissolved oxygen introduced from your previous splash racking is still active, and it may take a month or two for this to react with the wine, which will result in further free so2 drop. The theoretical drop of free so2 due to dissolved oxygen is 4 to 1, though in practice it can be anywhere from 2 : 1 to 4 : 1, for example if you dissolved 5ppm oxygen during the splash racking, you should expect to lose 10 to 20 ppm free so2 during the next couple of months.
 
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