I bought a gallon can of mushrooms like you use on pizza. As I started to open them, I thought, can I freeze the rest of these? Can anybody tell me if I can and how?
I freeze mushrooms all of the time. Place any leftovers that you have into individual use bags, or containers. Remember to label your container with contents and the date you freeze.
I also buy mushrooms by the gallon and freeze them, but I had trouble with freezer burn. So I now freeze them in half pint jelly jars. I fill the jars about 3/4 full (leaving room for expansion as they freeze. Pour enough liquid over them to cover. Pop them in the freezer. When I need mushrooms, I thaw them in the jar, either by setting it in hot water, or removing the lid and warming them in the microwave. Just an extra tip....you can buy sliced ripe olives by the gallon. Transfer them to quart jars...including the liquid. You don't have to freeze them. Just store in the fridge, and use as needed. I know they will keep for several months. I have never had any spoil before I could use them up. I use them on Pizzas and in salads.
I have not frozen canned mushrooms, but I have fresh ones all the time. I like to buy the large box of fresh, after I have used what I want, I slice the what is left thin and fry until the liquid is gone, put in a zip lock bag & freeze. When I need some I just measure out the amount and include them in my recipe. Always comes out perfect. I can't see why this wouldn't work with the canned ones.