The recipe said to add a parmigiano rind to the minestrone soup. I added an old hard piece of it, and the soup tastes great. My question: it's not a rind, it's just an old piece of parmigiano, but it did get soft in the soup, and as it cools it's getting hard again. Can I just keep using this over and over? It was so hard I couldn't grate it at all, I'm glad I saved it for the soup.