i have now had 2 beers get contaminated i dont know what i am doing wrong. I am doing all grain brewing and use star sans on everything post boil for 30 sec to 1 min (checking the pH of it each time). I plan on bleaching everything i have that i cant easily replace. I will buy all new tubing and after bleaching everything i will star sanz everything for atleast an hour. the contamination has come one on bottles and one kegging. Does anyone have any non obvious places for contamination that i might be missing. I am fairly new when it comes to brewing and i have had 3 beers not get contaminated and 2 that did. One thing i can think might have caused it was the rubber bung for the airlock as it is kinda old and i did have the beer get up to the airlock where i then replaced it with a blow off at it already pushed yeast up through the airlock. Any thought would be much appreciated