Combine 60 g (½ cup) of whole wheat flour + 60 g (¼ cup) of warm water in a large jar. Mix with a fork until smooth; the consistency will be thick and pasty.
Cover with plastic wrap, reusable wax wrap, or a lid and let rest in a warm spot, about 70-75 F for 24 hours.
Remove and discard half (60g) of your sourdough starter from the jar.
To the jar: Add 60 g (½ cup) of all-purpose flour + 60 g (¼ cup) of water. Mix with a fork until smooth. Scrape down the sides with a small rubber spatula.
Cover and let rest in a warm spot, 70-75 F for 24 hours.
Repeat the process of removing half of the starter and adding flour and water for Days 3-7, adjusting the amounts as specified in the recipe.
By Day 8, your starter should have doubled in size and be ready to use.
