[httpsterio]

Why I don't necessarily agree about tap water: many countries have excellent tap water and it's perfectly fine to use. If you have an automatic machine you might have to descale it a few times a year but it's perfectly fine for brewing coffee. Bottled water can often have more impurities than Finnish tap water.

Why I don't necessarily agree about temperature: coffee beans are already roasted at temperatures far hotter than 100 celcius. Any oils that would get lost due to temperature, have already evaporated at that point. If the water is too cold (like 90C or less), you risk under extracting the coffee. I think boiling is a perfectly acceptable temperature and don't notice any difference between that and 96C.

[fanf2]

In Britain the quality of tap water varies a lot from place to place. I live in Cambridge where the water comes from a chalk aquifer; it is very hard and has a distinctly unpleasant flavour. We got a water softener installed, including a separate filter for drinking water, and that made it a lot more palatable.

Last weekend we were visiting family in Sheffield, which is on the edge of the Peak District, and their water comes from hard sandstone hills, beautifully soft.