Raspberry wine, white film, too much k-meta

[siletzspey]

After a month of fermenting, and a few more weeks sitting still with "too much head space", my 3 gallon batch of raspberry wine developed a thin waxy patchy white film on top. After removing the film, I figured a dose of k-meta was warranted, but confusing tbls for tsp, I added 3x a normal dose. Assuming normal = 1 campden = 67 ppm, it seems I have ~200ppm in a still raspberry wine :-(

Not surprisingly, this rookie has questions, and I've read many very recent and past threads. Thanks for that! Firing away:

When racking carboy to carboy, does anyone ever add a spoon of sugar or so to compel just enough fermentation and CO2 generation that any oxygen is purged out?

For an infection, what k-meta dose is enough +/- pH adjustments?

Off gassing by stirring is highly recommended, but is this still appropriate and safe for a still wine/cider? Won't stirring risk another infection?

Adding hydrogen peroxide (per http://vinoenology.com/calculators/SO2-addition/ ) is another option, but some posters warn against it. As long as one doesn't add too much hydrogen peroxide, isn't it a safe and effective method? Also, when adding hydrogen peroxide, will out-gassing occur?

Thanks,

--SiletzSpey

 

[gratus fermentatio]

The sulfur dioxide gas generated by the potassium metabisulfate will dissipate over time. Gentle stirring will help to speed things up. Don't slosh or create bubbles, this will reintroduce oxygen to the wine. A gentle stirring for a few minutes once or twice a day for a few days should do plenty to help dissipate the SO2. Keep it under airlock when not stirring. Let it age at least 6 months.

Personally, I've never used hydrogen peroxide in a wine, nor would I. I see no reason to do so, but it's your wine, do as you see fit.
Regards, GF.

 

[siletzspey]

Follow-up -

It's been about 2 weeks since I overdosed to a guessed 200 ppm, and I've stirred once for ~5 minutes. I bought an Accuvin Free SO2 kit (~$34 for 10 tests), and just now measured ~65 ppm, and the pH is ~3.4.

Assuming I actually did have 200 ppm, and the test was accurate, I'd have to conclude it doesn't take much time or stirring to drive the S02 out. Whew!

The Accuvin chart suggests a free S02 goal of 20-32 ppm when at pH 3.4.

Any thoughts on how low the SO2 level has to be for any yeasties to work? Having added some sugars since the overdose, I'd like to see some final bubbles as validation the SO2 overdose is gone.

--SiletzSpey

 

[Yooper]

Follow-up -

It's been about 2 weeks since I overdosed to a guessed 200 ppm, and I've stirred once for ~5 minutes. I bought an Accuvin Free SO2 kit (~$34 for 10 tests), and just now measured ~65 ppm, and the pH is ~3.4.

Assuming I actually did have 200 ppm, and the test was accurate, I'd have to conclude it doesn't take much time or stirring to drive the S02 out. Whew!

The Accuvin chart suggests a free S02 goal of 20-32 ppm when at pH 3.4.

Any thoughts on how low the SO2 level has to be for any yeasties to work? Having added some sugars since the overdose, I'd like to see some final bubbles as validation the SO2 overdose is gone.

--SiletzSpey

The yeast may or may not recover from the overdose of k-meta. I wouldn't add sugar to a wine that was stuck, but if you did and fermentation doesn't restart you may have to make a starter and add some fresh yeast. I try to keep my sulfites around 50 ppm, generally adding k-meta at every other racking.

I definitely don't had more sugar when racking, as the idea of racking is to get the wine finished and clear and not restart fermentation.