Prepare the Apple Water

• Let 1 quart of tap water sit out overnight to remove any chlorine.

• Cut one apple into 1-inch chunks and place in a container along with the peel of the second apple. Add 1 cup of the prepared water, cover, and reserve the remaining water for later.

• Let the apple and water mixture sit covered at room temperature for 3 days, stirring daily. By the third day, it should be foaming slightly and smell like apple cider.

Build the Sourdough Starter

Day 1. Combine the whole wheat flour and bread flour. Measure out 150g of the apple water through a fine strainer and add it to 150g of the flour mixture. Whip vigorously and scrape down the sides. Cover with a frying pan spatter screen or a piece of cheesecloth. Leave at room temperature, whipping every few hours to incorporate air. Keeping the starter aerated during the first few days is important.

Day 2. Add 75g of the reserved tap water and 75g of flour. Whip and leave at room temperature, covered as before, for another 24 hours, whipping occasionally. Bubbles should begin to form, and the mixture should increase in volume.

Day 3. Transfer the levain to a clean 2-quart container, leaving behind any dried bits from the sides of the old container. Add 75g each of bread flour and reserved tap water. Whip and cover as before. If at any point the levain smells funky, discard half, replenish with flour and water, and whip more frequently. If it is not rising and bubbling, increase the frequency of feedings.

Day 4. Feed once more with the remaining 100g of flour and 100g of water. Let it sit at room temperature for 2 to 3 hours. The levain should be ready to use, though it will continue to develop flavor over the next few weeks. Cover with an airtight lid and store in the refrigerator.

Follow the care and feeding guide below.