Can I Add Sodium Metabisulfite To My Wine Now?

Here’s a question from a customer who has essentially aged his wine in bulk for a few months. He wants to know if he should be adding sodium metabisulfite at this time.
Sodium Metabisulfite———-
Fellow Winemakers,
Can I add sodium metabisulfite to my wine now?
I have 25 gallon of grape wine in 5 gallon glass jugs that I made in September of 2009 filled to the top no air space to stop bacterial infection can I add sodium metabisulfite before I rack the wine? and how long  should I wait before I rack the wine? I want to thank you for taking the time for all the information.
Thank again,
Richard R.

Yes, you should put in the sodium metabisulfite, but add it after you rack the wine, not before. If you add it before the racking, much of the sulfites will dissipate into the air. You should use a full-dose (1/16 teaspoon per each gallon) unless you have already added it before since the fermentation has ceased. In this case, I would suggest adding a half-dose instead.
In general, you should rack the wine after 5-7 days of fermentation, then again once the fermentation is complete. Then a final racking is done after the wine has clear. This can take anywhere from 2 to 6 weeks. You can bottle the wine at this time, or you can elect to leave it in bulk for a while to age.
Best Wishes,
Customer Service at Adventures in Homebrewing
Ed Kraus is a 3rd generation home brewer/winemaker and has been an owner of E. C. Kraus since 1999. He has been helping individuals make better wine and beer for over 25 years.