Along the same lines, I made some chocolate milk this evening with Nestle powder. While mixing I was reading up on the contest on the back of the container. Entries must be submitted by 08/10/99. It took me a full minute or so to realize it meant 1999 and wasn't a typo.
My husband also doesn't think it expires since it ferments for like 20 years before the sell it. Our bottle has definitely turned more brown. It's disgusting.