# Removing Potassium Metabisulphite from must



## KennethaBarnhart (Aug 27, 2013)

I mistakenly added 2.5 tsp of Potassium Metabisulphite to 6-gallons of blackberry must. I thought that I was Adding yeast nutrient (diamonium phosphate). By my calculations I added around 500 ppm which is way too high. I have racked it several times, splashing as much asI could. I imagine racking violently could reduce the concentration by half, but I would still have such a high concentration that yeast won't live in the solution. Nor do I know what level of sulphite it is safe to consume. I normally try to keep my wines to around 30ppm. Does anyone know how to measure the amount of SO2 in a must? I am thing I have two choices. 1. Mix the must with about 25- gallons of juice to dilute the concentration to a level that is reasonable 50ppm. 2. Dump it and be more careful net time. Thoughts? I wonder if boiling the must would cause the SO2 to vaporize? I read somewhere that peroxide would remove the SO2 but wonder if this would be a good idea...chemical soup comes to mind.


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## vernsgal (Aug 27, 2013)

Hi ,I'm kinda new at all this myself but i frequently check this site mostly and sometimes the net for info. I found this link, not sure how accurate it is, but maybe...
http://vinoenology.com/calculators/SO2-addition/

If anyone here has better knowledge on this I'd like to know as well ( I'm battling a problem of maybe too much SO2 as well)


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## gordini (Aug 27, 2013)

Yes, 500 ppm is a tad overdone. I go for 70 normally. 
Here is an excerpt from http://www.brsquared.org/wine/Articles/SO2/SO2.htm


Free SO2 can be removed by adding hydrogen peroxide (H2O2) to wine. The use of H2O2 is considered too severe by many. Nevertheless, it remains one of the only real options for removing excessively high levels of SO2 from wine for the non-commercial winemaker.


Solutions of H2O2 commonly come as 3% solutions. If they are mass/mass solutions (this appears to be the typical case) they should contain about 30.3 mg/ml H2O2. If they are volume/volume solutions they should contain about 42.3 mg/ml H2O2. (See "Information on H2O2 content" below for more details.)

So... in the following 1 mg/l is the equivalent of 1 ppm.

15 litres of wine has a free SO2 level of 70 mg/l. It is desired to reduce this to 40 mg/l. The reduction of 30 mg/l (70-40) requires an H2O2 addition of 16 mg/l (0.5304*30). Thus, the 15 litres requires an addition of 240 mg (15*16) of H2O2. Using a 3% mass/mass solution of H2O2, 7.9 ml (240/30.3) of the solution needs to be added to the 15 litres for the drop to 40 mg/l.

Make up your solution and add it very slowly while stirring, even wait a few hours in between additions because more SO2 comes out of solution at each treatment,until an equilibrium is reached.


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## RhynoMakingWineO (Aug 27, 2013)

Following along,....pretty interesting.....


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## Gwand (Aug 27, 2013)

Hi Gordini. Where does the .5304 and 30.3 come from? Thanks.


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## vacuumpumpman (Aug 27, 2013)

Whatever you do don't throw it out !
I am no expert on this - but I know that sulfite will displace in the presence of air, or in other cases of doing transfers back and forth using vacuum. 

I hope someone with more knowledge in this area will step in and give you even more advice


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## salcoco (Aug 27, 2013)

your numerous racks have most likely removed the SO2 from the must, To make sure make a yeast starter. Hydrate the yeast with sugar and water about a cup of water and two teaspoons of sugar,let it ferment a few hours, add must to double original volume , let ferment four hours, add must again to double the volume let ferment four hours add yeast starter to bulk must. adding the must to yeast starter acclimates the yeast to the must environment and also establishes a yeast population sufficient to overcome whatever so2 remains. Double check my instructions on yeast starter at Jack Keller's web site, his is proven.


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## salcoco (Aug 27, 2013)

http://winemaking.jackkeller.net/yeast.asp here is the page on yeast starter, scroll down to the proper paragraph. also once fermentation has started add nutrient Fermaid-K and stir must at least twice a day.


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## robie (Aug 27, 2013)

I agree with Sal. The idea is to add your must slowly to the starter so the yeast will have opportunity to get acclimated to the high SO2 environment.

After that, go ahead with he fermentation as usual, doing a splash racking when you rack. 

When sulfites are added to a wine, until a very large amount eventually has been added, much of what you add is almost immediately bound and no longer free. (I looked for the article that gives the amount but could not find it.) With each successive dose, less becomes immediately bound. So, if you added 500 PPM, right now an accurate free SO2 test would not reflect this amount. 

By the time you bottle, the level will have dropped significantly.

You may end up having to age this wine a little longer but my guess is it will be OK. Maybe open a bottle every few months and taste test. (Good reason to bottle a portion of the batch in 375 ml bottles.)


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## KennethaBarnhart (Aug 29, 2013)

KennethaBarnhart said:


> I mistakenly added 2.5 tsp of Potassium Metabisulphite to 6-gallons of blackberry must. I thought that I was Adding yeast nutrient (diamonium phosphate). By my calculations I added around 500 ppm which is way too high. I have racked it several times, splashing as much asI could. I imagine racking violently could reduce the concentration by half, but I would still have such a high concentration that yeast won't live in the solution. Nor do I know what level of sulphite it is safe to consume. I normally try to keep my wines to around 30ppm. Does anyone know how to measure the amount of SO2 in a must? I am thing I have two choices. 1. Mix the must with about 25- gallons of juice to dilute the concentration to a level that is reasonable 50ppm. 2. Dump it and be more careful net time. Thoughts? I wonder if boiling the must would cause the SO2 to vaporize? I read somewhere that peroxide would remove the SO2 but wonder if this would be a good idea...chemical soup comes to mind.



I want to thank you all for your ideas and encouragement. I decided to give the hydrogen peroxide a shot. I decided that my multiple racking probably reduced the sulphite level from 500ppm to around 300ppm. There is no science here just a guesstimate. I did the math on how much H2O2 3% solution was needed to remove 300ppm of Potassium Metabisulphite from my must. Based on the information provided in your input calculated that I needed to add 100 ml of 3% H2O2 solution to my 19 liters of must. I added 100ml, waited 3 hours, added another 100ml, waited about 4 hours, and then added 400 ml. I stirred the must each time I added H2O2. I then waited a day. I took a package of Cote de Blanc yeast into a glass bowl. I added 1 cup of water and one tsp of sugar and stirred the mixture until the yeast and sugar was dissolved in the water. I placed the glass starter bowl in a larger bowl of warm water, covered the bowls with a cloth. After and hour or so I could see that the yeast was working so I added a cup of the H2O2 treated must. After an hour or so I checked the starter. It was still working (bubbles) so I added more must ( about 2cups) to the starter. I also added a pinch of yeast nutrient. After another couple hours it was clear the yeast had been able to handle the sulfite in the treated must. I then added the starter to the 19 liters of treated must. I put an electric heater near the must ( in my garage) to keep the must and yeast warm. I checked the must in the morning and the yeast had survived and was working on the must sugar quite well. I added a teaspoon of yeast nutrient and left the heater on to be sure feeding conditions for the yeast were optimal (75-degrees).

I feel good about how this all worked out. Hope others gain from my adventure as much as I did. Thanks again!


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## vacuumpumpman (Aug 29, 2013)

I am glad that everything worked out for you !!


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## KennethaBarnhart (Aug 29, 2013)

KennethaBarnhart said:


> I want to thank you all for your ideas and encouragement. I decided to give the hydrogen peroxide a shot. I decided that my multiple racking probably reduced the sulphite level from 500ppm to around 300ppm. There is no science here just a guesstimate. I did the math on how much H2O2 3% solution was needed to remove 300ppm of Potassium Metabisulphite from my must. Based on the information provided in your input calculated that I needed to add 100 ml of 3% H2O2 solution to my 19 liters of must. I added 100ml, waited 3 hours, added another 100ml, waited about 4 hours, and then added 400 ml. I stirred the must each time I added H2O2. I then waited a day. I took a package of Cote de Blanc yeast into a glass bowl. I added 1 cup of water and one tsp of sugar and stirred the mixture until the yeast and sugar was dissolved in the water. I placed the glass starter bowl in a larger bowl of warm water, covered the bowls with a cloth. After and hour or so I could see that the yeast was working so I added a cup of the H2O2 treated must. After an hour or so I checked the starter. It was still working (bubbles) so I added more must ( about 2cups) to the starter. I also added a pinch of yeast nutrient. After another couple hours it was clear the yeast had been able to handle the sulfite in the treated must. I then added the starter to the 19 liters of treated must. I put an electric heater near the must ( in my garage) to keep the must and yeast warm. I checked the must in the morning and the yeast had survived and was working on the must sugar quite well. I added a teaspoon of yeast nutrient and left the heater on to be sure feeding conditions for the yeast were optimal (75-degrees).
> 
> I feel good about how this all worked out. Hope others gain from my adventure as much as I did. Thanks again!



I just read my post. I need to say that I added 30ml, then another 30ml and the 40ml of H2O2 to my must not 100ml, 100 ml, and 400ml as I stated above. My 65-year old brain sometimes isn't very trustworthy, sorry for any confusion.


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