I have prepared my starter from Chad Robertson's Tartine Book three times. Twice it grew mold. Once it never grew anything for almost a week. I am using the exact recipe and clean utensils. What am I doing wrong?
Update/Comment on Oct 1: I used brand new bread flour and wheat flour 100 grams. I live in Tennessee so it is humid. I used tap water. Should I use bottled? Had a cloth lid.