"Is it really though? I've lived three places in London and made sourdoughs with tap water in all with no trouble." That's interesting. I haven't made real sou

"Is it really though? I've lived three places in London and made sourdoughs with tap water in all with no trouble." That's interesting. I haven't made real sourdough for a long time, but I do bake bagels, bread, and pizza dough pretty regularly. While London tap water does work, I've noticed on many occasions that the dough rises a lot faster and requires much less yeast when using filtered or bottled water (I usually use the cheap Tesco Ashbeck water that you buy in big 5L bottles) compared to using straight tap water. But whether this is due to chlorination or other factors (London water is notoriously "hard", too) I'm not sure.