Sulfite PPM levels

[WTD]

google tells me alot about sulfites but i want to ask around here. Its hard to tell whos right as they are all different

Is PPM the milligrams per Litre? so if i add one 440mg campden tablet to 5L demi it will be 440ppm divided by 5 which equals 88mg/L, is this 88PPM?

what is a good sulfite level for a red wine to be stored a few years? google says some comercial ones can contain up to 200ppm for dry reds but no more as regulations dont allow it?

Is 88mg/L good enough to store for at least 5 years or should i do 2 campden tablets like the packed says which makes it 176mg/L (176ppm????).

Ive done the 2 like the campden box says in the past but im wondering if this has been over kill and i can get away with using one at first racking after secondary.

Reason i ask is im going to buy alot of shiraz grapes and i dont want to use too much or too less sulfites. looking for a good ball park figure. If it is a tad high can a decanter fix any smells issues?

I dont have a Free SO2 kit.


Thanks

 

[jgmillr1]

1) Yes, ppm (parts per million) is mg/L
2) Potassium metabisulfite contains 57.6% SO2, so a 440mg campden tablet per gallon should yield 67ppm. You don't want to use sodium metabisulfite.
3) A proper sulfite level depends on the pH. A red wine should nominally have 0.5ppm molecular SO2 (whites are 0.8ppm). At higher pH, you need more free SO2 to achieve the same molecular SO2. A table is here. Note that you should KEEP the sulfites at this level, which means periodic additions. When you rack, you will lose a lot of sulfites (say, 20ppm or so). Aging wine will reduce sulfites by 5ppm per month or so. No way of knowing for your set up without measuring them.
4) It is best not to over-sulfite the wine as this can kill the nose on it, even if you are able to decant the wine below a noticeable threshold. Use the sulfite chart in (3) to assist with maintaining a good level.