First post here

I recently upgraded my Silvia to Linea Mini (and loving it), and in the process of doing so, I've been reading a lot of discussions and informations on water quality, and one idea came to mind -

What if dual boiler machines has two water input?

One for the brew boiler, and we use water that's good for taste. be it the SCAA guideline or whathaveyou.

Another for steaming, and we use much softer water (because what's taste the best for espresso isn't the best to prevent scale build up, but also it should not be too soft so that it eats all the brass of course) for it. Since it's steam coming out, and water there doesn't quite affect the taste of steamed milk. But by doing so you reduce scaling where it most likely to happened - in the steam boiler.

Sounds like a good idea if you can accommodate it technically...I would expect that you need to clean/drain the steam boiler at some point to get rid of build up residue like you would have to anyway but scale should not be an issue.

Synesso has separate steam/brew boiler water line inputs already but for a different intended reason. Namely to minimize/eliminate shot pressure fluctuation should a steam boiler fill trigger during a shot. Steam boiler fills from line pressure before the pump inlet. So you could feed different water to the steam boiler but I don't know anybody who does.