So, when I first started brewing I never had this slight flavor in my beer and then all of a sudden it appeared and I could never figure out why...until possibly last night. When I first started brewing I always used air locks. Then, one day for no real reason I decided to switch to aluminum foil over my carboys. I never connected the the possibility of this being the cause, until last night as I lay in bed and was thinking about cold crashing (I do it for three days on my beers) and all of a sudden I thought, "oh my god, that off flavor tastes a little like my chest freezer smells!" Since using the aluminum foil isn't air tight...is there a chance my beer could pickup the smell from my chest freezer and infuse it into my beer in a three day time period?