Originally Posted by Honda88
Lately I have been adding pottasium metabisulphite to my musts prior to fermentation but I was wondering is this really neccesary when using frozen concentrates? I dont think yeast or bacteria could tolerate my deep freezer. What I was going to do was just let the must get down to a pitchable temp and pitch the starter? Anything wrong with this?
No, it's generally not necessary although wild yeast could probably survive in your freezer. Often frozen concentrates have sulfites added as a preservative anyway.
Sometimes, though, just while the juice thaws and before the yeast starts fermentation the must may be susceptible to contamination. It won't hurt to use k-meta as a safeguard, but you may be perfectly fine without it as well.