In a clean container, mix together 1 cup whole wheat flour and 1 cup water until no dry bits remain.

Stir the mixture thoroughly, then cover the container loosely with a clean towel or coffee filter secured with a rubber band or string to allow airflow.

Place the container in a warm spot (70°F to 75°F) and let it sit undisturbed for 24 hours at room temperature.

After 24 hours, discard half of the starter and add 1 cup all-purpose flour and 1 cup water, stirring until combined.

Repeat the feeding process every 24 hours by discarding half of the starter and adding 1 cup all-purpose flour and 1 cup water each time, for 5 to 7 days.

After about one week, check for activity; the starter should be bubbly and double in size within a few hours of feeding.

Test if the starter is ready for baking by dropping a spoonful into a glass of water; if it floats, it is ready.

Store unused starter in the refrigerator and feed it once a week to maintain its activity.