Hi Larry, very good question. Wine making yeast is one of the only micro organisms that can survive the sulfites used to stabilize a wine.

This is why you’ll often see fruit wine recipes that call for sulfites be added to the fruit juice 24 hours before you add the yeast. The sulfites kill off the wild yeast and spoilage micro organisms and allow the wine yeast to come in and dominate the fermentation.

Was the sulfites supposed to go in after fermentation per your kit instructions? -Matt

In general the best way to stop a fermentation is to use a sterile filtration system. Filters with a mesh of 0.45 microns or finer will actually remove single celled organisms from your wine, yeast or spoilage organisms.

I hope this helps Daniel! -Matt

Hi Mark, great question! The potassium metabisulfite is used to stabilize the must is to know out any stray micro-organisms to compete with. Wine yeast just happens to be strong enough to deal with reasonable levels of sulfites so there’s a chance that the yeast you’ve previously added.

I would recommend giving the must a little time to see if the first dose of yeast can power through the sulfite dosage. The good news is that your wine will be protected from everything else too so you aren’t at a great risk of spoilage or other micro-organisms.

You can pick up yeast flavors in a finished wine if you add too much yeast to the must. Giving the must 24-36 hours or so to see if fermentation begins shouldn’t hurt anything and may help you avoid yeast flavors in the finished wine.

Please let me know how it goes for you and what you decide to do. Cheers! -Matt

Gary, thanks for sharing your experience! Avoiding sorbate is a good idea when you can. I was really surprised when I found out what it can do to the flavor and aroma profiles long term. I truly believe that the more we know about the wine making process and the additives that go into it the better our wines will be. I hope this is your experience as well.

Thanks Matt. I will heed your advice and leave that batch alone. More importantly, I will know for my next batch to use potassium metabisulphite.

Hi Mike, that’s a really good question. I do not recommend adding at the potassium metabisulfite at this point.

The most important part of either additive is the sulfites. Potassium and sodium are used to bind SO2 gas and keep it in a solid form. Once it hits your wine and dissolves the SO2 gas is released and we no longer have any use for the potassium or sodium.

If you were to add potassium metabisulfite on top of sodium metabisulfite I would worry that your sulfite levels would be too high. You would then need to test your wine to determine if the sulfite levels are safe for you to consume the wine.

Sodium metabisulfite can impart a salty taste over time but likely this won’t happen with just one dosage. If you plan on doing subsequent sulfite additions I would then recommend switching to potassium metabisulfite but if that was the last dose then don’t worry about it.

I hope this helps Mike!

Matt