When boiling potatoes, I like to use the leftover water for soups, sauces, etc. Does anyone else use potato water, and if so, how long can it be stored in the refrigerator? I am wondering if it has a "shelf life" similar to homemade stock.
Yes, shelf life would be similar to homemade stock. It has the same potential for cross-contamination, and natural contamination (with a slightly reduced chance for contaminates from ingredients, as there is no meat).
Be sure to cool and refrigerate quickly (cool pot in a sink of ice + cold water). If left to sit out, warm + starchy water is a great breeding ground for un-fun microbial life.
My Mother-in-law uses it frequently. She uses it for soups, etc... She also uses it when making it bread. She tells me it's cause it gives the dough a nicer texture.
She'll stores it for a couple weeks sealed properly (in canning jars) I think.
Although as I'm thinking now, I don't see why you couldn't freeze it...