Er, it's just standard water for me and my homebrewed beer. There are a million and one things you can do here to obtain a water with the best chemical composition for homebrewing but myself, I'm being very lazy. It's commonly held that the best water in the world for brewing comes from Burton-on-Trent due to its mineral content, and for many years, a great number of breweries based themselves there.

These days you can add the powdered equivalent if your local water supply doesn't have much in the way of dissolved minerals. At the moment, as I'm keeping things simple, I'm just brewing with what comes out of the tap.