Hello everyone, I have a Coleman Xtreme 70-Quart cooler, http://www.walmart.com/ip/Coleman-70...Cooler/4807332
, that I converted into a mash tun. I've done several all grain batches from it but had a time in which it got away from me and spent grain sat in there longer than it should have post completion. After cleaning it all up and getting it sanitized I notice a bit of the plastic now is an off yellow/brown color. I've brewed a few batches since this and notice just a subtle off flavor in each beer. Is this possible that I've allowed the plastic walls in the cooler to absorb something from that old spent grain that now I've ruined the mash tun? My stainless steel braided cable does have a few rust spots on it and I utilize brass fittings/ball valve at the other end. I've considered getting a new mash tun and learning from this mistake but I want to make sure that this is an actual possibility before I chuck it. Thanks everyone!