In a wide-mouth 4-cup jar or bowl, combine ¼ cup wheat flour with ¼ cup all-purpose flour. Add the water and stir until you see no dry flour. Cover loosely and leave it in a warm spot for 24 to 48 hours.

On Day 2, check for any signs of activity such as bubbles. Stir the mixture if necessary and let it sit for another 24 hours.

If you notice bubbles on Day 3, discard half of the starter. Add ½ cup all-purpose flour and ¼ cup lukewarm water. Stir to combine, cover loosely, and rest for another 24 hours.

From Days 4 to 7, discard half of the starter each day and feed with ½ cup flour and ¼ cup water daily. By Day 7, your starter should be ready.

To test if your starter is ready, see how long it takes to double in size or perform the float test. If it passes, it's ready to use in baking.