Day 1: Combine 70 grams filtered water and 70 grams bread flour in a non-reactive bowl. Stir until smooth. Cover loosely, and place in 70° F to 75° F area. (See Notes 4 and 5)
Day 2: Add 70 grams filtered water and 70 grams bread flour to Day 1 mixture. Stir until smooth. Cover loosely, and place in 70° F to 75° F area.
Day 3: Pour 140 grams of starter into a clean bowl, and discard the rest. Feed the 140 grams with 70 grams each of filtered water and bread flour. Cover loosely, and place in 70° F to 75° F area.
Days 4 - 8 or 9: Each day, pour 140 grams of starter in a clean bowl, and discard the rest. Feed the 140 grams with 70 grams each of filtered water and bread flour. Cover loosely, and place in 70° F to 75° F area.
Day 9 or 10: When the starter becomes more active, pour 140 grams in a clean bowl and discard the rest. Feed the 140 grams with 70 grams each of filtered water and bread flour. Cover loosely, and place in 70° F to 75° F area. (See Note 5)
The starter is ready when it is nicely fermented, smells a bit sour, and doubles in volume within 2 to 3 hours of it being fed. (See Note 6)
Refrigerate the starter, loosely covered until needed. Generally, the mature starter should be fed as on Day 3 about once every month.
Two days before making bread using a refrigerated starter, refresh the starter by feeding it at room temperature each of the two days. The refreshed starter can be used make bread on the third day. Before returning the remaining starter to the refrigerator, set aside 140 grams and feed it with 70 grams each of filtered water and bread flour.