Question:
Anybody ever brewed with one of these? I am out of carboys and the LHBS is closed on Sunday, and I am itching to brew. The plus side is that I get 5 gal of fresh spring water with a known mineral content. Plus, its got a handle on the side of it which is sweet as far as I am concerned. What are some bad sides that I don't know about? Is that plastic nonreactive/reactive? Anything else I should know about it? I see that the LHBS is now carrying PET carboys? or something to that effect with a spigot near the bottom. Anybody using those? Comments welcome.

Answer: The water cooler plastic carboys work alright for primary fermentation, but I would not want to do a long secondary in them. The main issue with them is that oxygen will diffuse through the plastic and into your beer over time.

The "better bottle" PET carboys are way overpriced and do not offer any real advantages over traditional glass carboys or plastic buckets. IMO, don't waste your money on them.

None of the plastic containers are impervious to O2 but they have very slow permeation rates. None of that matters during primary fermentation because any O2 that gets through is either consumed by the yeast or expelled through the airlock by the CO2 generated.

Water bottles are typically polycarbonate and offer just slightly less protection than PET (the Better Bottle is PET). PET is good for CO2 as I suspect polycarbonate is but still has issues with O2 permeation. Permeation is not why they chose to use PET over PC. Toughness is the real reason.