Here's a thread on the kinds of plastics to avoid for fermenters:
i know this topic has been exhausted throughout the brewing forums, but I haven't hear much advice/talk about #7 plastic. My wife bought some cheap three gallon water bottles from target for four bucks a bottle. The bottom says for water use only. My thought is....although most people say to...
Crazy enough the often bluish tinted water bottles typically used in water dispensers appear to be made of #7 plastic.
It may be OK for plain water use, but definitely NOT
when the beverage contains alcohol
#1 (PET) and #2 (HDPE) plastics are commonly accepted to be safe when used as fermenters.
Most clear, highly transparent, plastic fermenters
, such as "plastic" carboys (Better Bottle
, Big Mouth Bubbler
, etc. are #1 PET.
Most opaque white containers such as 3.5 or 6.5 gallon Brew Buckets
, 3-4 gallon buckets your local bakery gets their icing in, etc. are stamped #2, being HDPE, and safe to use as fermenters.
Avoid such vessels with color (such as orange Homer buckets). Colored #2 lids
are probably fine, as they're not touching the alcohol containing beverages such as beer, cider, wine, etc.
If you don't have a well fitting (rubber) bung, use a piece of sanitized plastic or small-bubble wrap, wrapped several times around the airlock stem to make a "plug" for the opening. Then, for good measure, wrap a piece of sanitized plastic wrap around the neck and "bubble wrap plug" to "seal it off," to keep nasties out.
Once you know you're serious about homebrewing, get a copy of John Palmer's How to Brew
, 4th Edition.
And read/search HomebrewTalk
and ask questions to get the nitty gritty, and different opinions.