Agree too! Some matter collecting is inevitable ... it's the grain proteins precipitating out ("break"). I wipe it off with one of those soft microfibre clothes. This if the inside of my Grainfather after numerous brews:
Given the amount of burning on
@Buffers brewery's earlier pic, I think you can safely say that older boiler was getting way too hot, or ... the water treatment then was ineffective!
Yeah, I know, so I have a "hard water" prejudice! And "chalk" precipitating out and sticking to the hot element surface will roughen up the surface, cause the break to stick to it, where it will burn. But there's a problem with that: We treat the water so we are
all using near enough the same water for a particular beer. The "hardness" of the original water has nowt to do with it. UNLESS, you weren't treating your sparge water, at least by acidifing it (considered by some to be unnecessary, but here we have an example where it
would be necessary!), or whatever the previous water treatment, it wasn't having the desired effect (still loads of "chalk" in the water to precipitate out on boiling).