Originally Posted by ultravista
I just don't see how a cover, over a glass carboy, could affect the flavor of the beer inside a sealed container.
if light can pass thru into the beer, it can harm the beer. a white plastic trash bag isn't exactly the best cover. if you put your head in a white plastic trash bag (please don't do this, just imagine it), you can most definitely see light. So if you can see light, so can the beer, which isn't a great thing.
OP, if you want to use trash bags, just stick to the 20 mil contractor yard bags. u could tie the carboy up in that and ferment it outside if you wanted to, no light's gonna get thru that. (don't ferment outside, i was just using it as an example).