Why food grade plastic?

[oldbloke]

Stainless steel's great. Everything else, not so much. Especially at any stage where your liquid is acidic. Aluminium, just say No.

 

[Loetz]

One of the fittings I have for my BK is made of Rotguss AKA Gunmetal AKA Bronze.

Do I need to throw this out and find a new one?

 

[Loetz]

And what about rubber?

I have some black rubber seals that I plan to use to hold my ball valve for my HLT in place. Do I have to worry about those things touching the hot water?