Put water in bowl and dissolve about 10% of the flour and mix for a minute. Add yeast and mix for another two minutes.
Add half the flour, increase speed gradually. Keep adding the remaining flour, a little bit at a time. Mix for five minutes at high speed.
Put flour on workbench, remove dough from bowl and knead in salt.
Put back into KitchenAid and mix for another five minutes at high speed.
Put flour on workbench.
Transfer into large bowl. Cover bowl with plastic wrap, use rubber band to make it airtight. Let the dough rest for 16-20 hours at room temperature.
Put flour on workbench. Take dough out, knead gently. Cut off 250g pieces and shape into balls. Put into tray and cover with wet cloth or plastic wrap. Let balls rest for another four hours.