I have a milk jug with potassium metabisulphite in it for sanatizing and for my air lock.. how long with it last in the jug before I need to mix a new batch.. ?
Usually about 3-4 months but watch it as the milk jugs that I used to store it in sprung leaks, I guess the stuff was to potent for the plastic milk jugs I was using.
Yes, plastic milk jugs don't hold up real well to sanitizer strength bisulfite. I use a gallon glass jug and it lasts for about 6 months. If a sniff stings the nose it is still good.