how much sulfite during fermentation

Unless you want a slightly sweet/medium wine my advice would be to allow your wines to completely finish fermentation, then rack and add one campden tablet to each gallon - store, then bottle.

If you rack while fermentation is still going and add the tablet now you'll kill the yeast and end up with a sweet/medium (and possibly low alcohol) wine - is this what you're aiming for?

Many people add 50 ppm at the start of fermentation to inhibit wild yeast. After fermentation you should consider adding it to protect from oxidation. But there is no reason to add it during fermentation. Wait until you rack it after all fermentation is ended.

Ray

I'm looking to give the must/wine some initial oxidation protection. Wine yeasts are somewhat sulfite tolerant as opposed to wild yeasts and I'm looking for how much to add to allow fermentation to continue. I seem to remember some recipes that had you add 1 campden prior to adding the yeast.

Don

Don, In general, sulfur dioxide should not be added to an active fermentation. lum

Thanks Ray and Lum, My concern here is that my mango has about 2" or 3" of gunk at the bottom of the gallon jug I was going to rack it off that but it's still very slightly fermenting. I was going to let it sit under an airlock for another month or two and wanted to give a very slight protection from oxidation in the racking and until the CO2 builds up in the headspace again.

I may just shake the jug abit after racking to release some CO2.

Don

fermentation.

Don, Fermentation is a multi-step process. Acetaldehyde is produced in the next to last fermentation step, just before alcohol. Sulfur dioxide reacts strongly with Acetaldehyde. When SO2 is added to active fermentations, the SO2 reacts with the Acetaldehyde. Excessive amounts of Acetaldehyde is left in the wine, and little or no free SO2 remains in the wine when fermentation is finished. This is why adding SO2 to active fermentations is usually not a good idea. Regards, Lum Del Mar, California, USA

I'd recommend that you get the wine off of that thick layer of lees and then lrt it finish its fermentation. You may dodge an H2S bullet that way. If you insist, save the gunk, let it ferment out and settle and then taste and smell it to see if you want to add back the clear part to the rest of the batch.

Tom S

If you rack off of a slightly fermenting must, leaving the sediment, you run the serious risk of sticking the ferment. Most of the yeast is down in that sediment. If you want you could stir the sediment. This cuts down on the SO2 that might develop from it. But I would recommend against racking off the leas. But if it is really worrying you, it is yours so do what you want. We can only make recommendations based out our experience and many of us have opposing experience.

Let us know what you decide and how it comes out.

Ray

fermentation.

Thanks for all of the replies, I racked it off the gunk into a new gallon jug without adding sulfite. It was a bit of a fiasco as it clogged cheese cloth, fine mesh kitchen strainer and just about everything else. Got it done though and now there's about

1/2" of gunk again. Oh well I'll let it sit for a month or so, check the SG and sulfite it if it's done.

FYI on straining when you have this much gunk, don't try to get it all removed in the first rack, use a coarse strainer and plan on successively finer ones in two or more racks. When you only have a gallon there's not much that you want to throw away.

Don

Don, I would not add SO2 to an active fermentation either, but if you want it off those lees, why not rack to a smaller container and let it go from there? I'm not sure what I would do either.

I would probably just taste and smell it, measure the SG and if I had no off odors or odd taste shake it up to stir the lees and let it finish on it's own. Regards, Joe