can i use a plastic 5 gallon water jug for a carboy when fermenting my beer?

Answer 1

It's not recommended but it will do the job.
You must sanitlize it before you do, and use it only once. Use very hot water, no chemicals to sanitize.
After the fermentation is complete, rack the beer to bottle or keg immediately! Don't let the beer rest there.
After you have used it it will harbor a ton of nasty bacteria that will foul the next batch, so discard it.
The problem with plastic is keeping it clean.

Answer 2

I have a couple of buddies that make their own beer and they both use a combination of those plastic water jugs and glass carboys to make their beer and I can't tell the difference, so I would have to say yes, even though I have always used glass myself

Answer 3

Those water jugs are not food-grade plastic, which means that some chemicals in it can leech into the beer. They are also very air-permeable, which could result in oxidizing the batch. Finally, you can't probably attach a stopper to the opening because of it's jagged edge.

To answer your question in a word, 'no.'

Answer 4

you should make sure to use a foodsafe type of plastic jug..look into it before its too late...they prevent contamination.