Cheap and easy to make hop back.

[SHIELDS EXILE]

After trying all sorts of biabs homemade and bought, I cut habit of75mm water pipe,PVC, and cut a dozen hacksaw slots halfway through it, and wedged it in my mash run across the bottom inside between the back of the outlet tap and the opposite wall of the vessel,an old 23l fementer'it works better than any biab, and is easy to clean.

[vacant]

Food safe pipe?

[SHIELDS EXILE]

If it is good enough for a drinking water supply it should be good enough for malt at 66 deg.c for 1.5 hr mash, after all most home brew kits are fermented in plastic.

[vacant]

Drinking water suitable sounds good. Some plastics can leach affecting flavours, some plastics are made from recycled material that could have contained anything (toxic metal compounds perhaps). Food safe plastics should be free from either of those problems.

[SHIELDS EXILE]

you could use abit of stainless steel if you like.