I was wondering if there is a shelf life for malt extract. I found a beer making kit at a garage sale that had Munton and Fison brand Malt Extract (wheat). The cans seem maybe just slightly swelled at the top and bottom, but I can't tell if that's just the normal shape of the can. Anyone have experience with this product or shelf life in general? I have no idea what conditions these supplies have been kept in. Thanks!