On water...

One thing I did not talk about in my overly long discourse on espresso (was there anything I did not ramble on about? Believe it or not, yes. Lots. Coffee is a very complicated matter, but well worth it) was water. In Oakland we have soft water. In Sacramento it is hard water. I use water right out of the tap and have never had any problems with it. I also drink water right out of the tap, seeing the filtering movement as nothing more than secular neo-Puritanism. Flouride is good. Trace amounts of chlorine that kill nasty microorganisms are good.

I have found that when someone is going on a little too long about water purity and they are talking about the modern Western world, not some place where the municipal water authorities have not yet figured out that the cloaca and the drinking water tube should be distinct from one another, the chances are great that they are trying to sell you something. I don't stick to pure grain alcohol and rainwater, and I seem to be doing OK.

But back to water for espresso brewing:

The only concern with hard water is that minerals can build up in your machine. This problem is solved by, once every few years, running white vinegar through the works, immediately followed by several runs with distilled water, until no more vinegar can be smelled or tasted. If a little, teeny hint of vinegar is there, it will go away after the first couple of real shots brewed.

So my basic rule is this: if the water is good enough to drink, it is good enough to make espresso with. Sort of like mixing concrete. Just don't drink the concrete.