bisulphite in grape wash - help.

Information about fruit/vegetable type washes.

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udiraz
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bisulphite in grape wash - help.

Post by udiraz »

Hi. you can read the first question I had, about fermentation and vinegar here:
http://homedistiller.org/forum/viewtopi ... =3&t=51081

Shortly, I got 200 KG of grapes. juice measured 1.086 SG which I think is nice, the grapes guy put potassium metabisulphite in it, and the morning after I also added some , because I saw that it is fermenting without any yeast I added, and I did not want any contamination there. Now, after what NZChris wrote me, I understand I was mistakenly doing that, and I am likely to have stinky brandy from the metabisulphite.
I guess there is about 10 grams of potassium metabisulphite in 40-50 liters of grapes wash.
My still is alembic copper still (you can see it here http://homedistiller.org/forum/viewtopi ... 6#p7208476)
It is fermenting for only one day, but I want to be ready as much as I can to the distillation with solutions to the possibly stinky distillate.
I read about some solutions, espseciaaly hydrogen peroxide, and some copper sulphide or something like that, but I did not find anything really practical and from someone's experience.

Can you guys try to guide me what to do in case, and what should I get my hands on to be ready for possibly stinky distillate ?

Thanks you all !
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Paulinka
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Re: bisulphite in grape wash - help.

Post by Paulinka »

If it is really oversulphured the best solution is to dilute with unsulphured fruit juice, if you don't have grapes then apples will do it. Good news is that a lot of copper in a pot like yours will catalyze most of the sulphur, so I should not worry about it. If you want to be sure then aeration (maybe bubble-aeration?) can help before cooking, you will not lose much alcohol but some of the sulphur will air out.

There is another technique I just read in a very old vintner's book: after fermentation pour in some (it didn't mention how much) sulfurous acid (H2SO3, not sulfuric acid which is H2SO4) in a barrel, and pour the oversulphured grapewash on top of it, mixing it. It is said that sulfurous acid will bond with the free sulphides, creating sulfuric acid, which is pretty much harmless to distill *- most of us in Hungary use sulfuric acid (battery acid) to level the pH of fruitmashes for pálinka. It is not distilling through and completely safe.
(*over a few decades it will thin out your copper from the inside, but only after huge numbers of cooking)

"it is fermenting without any yeast I added" I would still drop in two packets of Fermivin PDM or other killer-active vintners-yeast for a controlled fermentation, it is not too late.
udiraz
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Re: bisulphite in grape wash - help.

Post by udiraz »

Thanks Paulinka !
These are helpful advices.
I think what I will do is aerate the wash before the distillation - with some aquarium pump and an air stone. For how long you think I should aerate it ? 1 day ? two days ? I don't have a clue... maybe racking it several times will be enough, or is it not enough ?

I don't smell any sulphuric like smell (rotten eggs ?) from the wash, although some of the fermenters (I have total of 5) smell better than others (that means that the others smell less good, but I cannot identify exactly, and it is very very very weak). It also tastes good for a wine that made from eating grapes and did not age even for a second. So maybe I will be ok with aeration and the copper still.

Some guy here (MDH - thank you man !) instructed me about how to treat the low wines with copper in case it smells bad, and since the wash does not smell bad (not to me at least), if something is wrong - I will know after the stripping run.
I also think I will distill the wash from each fermenter separately, so that if one is foul, I will still have the others good.

About the yeast - I added my wine yeast a day or two after the grapes were crushed. it is montrachet yeast from some italian brand.

What do you think ?
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Paulinka
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Re: bisulphite in grape wash - help.

Post by Paulinka »

I think that it will turn out great, no need to worry. A day of aeration will be perfectly enough, and separate distillation in 40L batches is a very good idea, just to be sure. However, that yeast was not an optimal choice though as it is known to produce more hydrogen-sulphide than other strains, especially if there are a bit more sulphur in the mash than usual, but aeration and that much of copper will solve it. I would cook the mash a little slower than usual to give time for the sulphur-fumes to react with the copper, and aerate the low wines too before distilling.
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