Cool tips, thanks folks. I may try the fridge thing.. I've been using the same bladder off and on for at least 10 years, and this summer the water tasted a little more funky than I remember. I wouldn't normally care except the kids like to drink from them now too, so which has raised the issue.
82 fj40, 99 uzj100, 06 gx470
97 DR650, 05 525EXC, 01 XT225, 89 TW200, 09 TTR125, 07 TTR90, 07 CRF50