If you have frozen fruit (like I do) for months do you need to use Sodium Metabisulfite when you start the wine brewing process or does the freezing kill all the bad stuff.
Unfortunately, freezing does not destroy mold, bacteria or other “bad stuff”. It simply puts its growth into suspension, or hibernation if you like. Freezing will damage some of the cells with freezer-burn, but not nearly enough to save your fruit from needing a sulfite treatment of some kind. You will still need to add sodium metabisulfite before using it to make wine.
Even though freezing does not eliminate potential spoilage, it does temporally stop the spoilage process. This is great for someone trying to save up enough grapes to make some homemade grape wine.
Often in a small backyard vineyard, the grapes will not ripen evenly throughout the rows. In this situation you can freeze what ripens early until you have enough saved to make a batch of wine. Just realize that you will still need to add sodium metabisulfite to the batch before fermentation and again, before bottling, regardless if the grapes have been frozen or not.
I hope this answers your question. Nothing wrong with freezing fruit. It just doesn’t eliminate the need for sulfites.
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.