Brita

The upgrade nobody thinks of, because it isn't a coffee product.

Almost everything in your cup is water. If yours is hard, you're tasting the limescale as much as the coffee, and you're quietly furring up whatever machine you spent money on.

One jug here, the starter pack at £31.50 with a filter in it. For the price it will change how your coffee tastes more than a new brewer would. If a machine already needs rescuing rather than protecting, that's the descaling page.