I bought some Ronnybrook heavy cream a week or so ago, figuring I would use it for whipped cream on Thanksgiving. But of course I had to open it and have some in my coffee immediately. Since it's not ultra-pastuerized, it started smelling funny, and separting a little after a few days: but this morning it's all lumpy. So I almost threw it out, then realized this is probably really good sour cream. I could put it in the mashed potatoes Thursday! Or am I wrong?