I have just started a batch of mulberry wine (23L) and accidentally added
10g of PMS instead of the 5g I needed for doing a cold soak. The must has a definite sulfur smell and even after stirring every morning and night for the last 3 days to agitate the yeast still won't start. I pitched with lalvin D47 first and have pitched another 500mL with RC212 to try and get one going. How can I reduce the SO2 to get the ferments going ?thanks in advance
JH
Wait, if you're still on some skins they will take up the SO2, give it a stir to introduce some O2, this will help to drop the level.
You can also use Hydrogen Peroxide, but on a small batch like this I would be hesitant, you can badly oxidise the juice if you add too much or too quickly
Try aeration, or H2O2 if you require something more drastic. See "Removing Free SO2" at
Ben
You have in excess of 200 ppm free SO2 in that must. I doubt that you'll get it to go without treating it with hydrogen peroxide. (FWIW, I think that even half the amount you added would have been too much by about double.)
If you decide to use peroxide it'd theoretically take 190 ml of 3% solution to react all of the added SO2. I wouldn't go that high though, since it'd be good to leave _some_ in - plus you've reacted some of it away by splashing the must, and the initial potency of your K2S2O5 is an unknown. Start with 100 ml of 3% H2O2 and try pitching the yeast again.
Tom S
That's a lot of SO2. Even your 5 grams/23 liters is about 125 ppm. I think 2 grams for 23 liters would be more appropriate.
Hydrogen Peroxide is probably your best course of action now.
Andy
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