To ‘feed’ the starter, stir 100 g flour and enough tepid water into the starter to make a soft, paste-like dough. Cover the bowl as before and leave for 24 hours. At this point the starter will look very active and bubbly. Stir well, then discard half the starter. Stir another 100 g flour and enough tepid water into the starter to make a soft, paste-like dough. Cover again and leave for 12 hours. If the starter looks very bubbly and lively, it is ready to use. If it seems only slightly bubbly, give it one more feed of 100 g flour and tepid water and wait 6 hours.