Step 1

For best results, weigh your flours; this recipe was developed by metric weight. However, if you prefer to work with volume measurements, please be sure to measure your flour the King Arthur way : gently spoon the flour(s) into a cup, then sweep off any excess.

Step 2

, In a large bowl, stir together the flours and salt.

Step 3

, Add the starter to the flours. A level muffin scoop (about 1/4 cup) is just the right amount.

Step 4

, Add the lukewarm water; warmer water will shorten the rise a bit while cooler water will lengthen the rise time. Use a spatula, sturdy spoon, or dough whisk to mix everything together.

Step 5

, Once the sticky dough comes together and no floury spots remain, switch to a bowl scraper and give the dough a few more brisk turns, mixing until everything is totally combined. If you want to use a stand mixer, mix with the flat beater on medium-low speed for 45 to 60 seconds.

Step 6

, Cover the bowl and let the dough rest until it puffs noticeably and nearly doubles in size; overnight is your best bet.

Step 7

, Lightly grease a 9” x 4” x 4” loaf pan. If desired, coat the inside with sesame seeds for extra flavor and crunch.

Step 8

, Using a bowl scraper, move the dough to the center of the bowl, gently deflating it in the process. Continue to scrape the dough into the center of the bowl for an additional 20 seconds or so, until it comes together in a jiggly, semi-elastic mass, something you can easily scrape over the edge of the bowl into the prepared pan.

Step 9

, Scrape the sticky dough into the prepared pan and smooth the top with wet fingers. Tent the pan with your favorite reusable cover and let the loaf rise until it’s within about 1" of the rim of the pan. This will take about 3 to 5 hours, depending on your room temperature.

Step 10

, About a half hour before the dough is ready to bake, preheat the oven to 425°F with a rack in the center.

Step 11

, Uncover the risen loaf and place the pan in the oven. Bake the bread for 45 to 55 minutes; it should have a pale brown, crisp top, and should pull away from the edges of the pan when done. Its internal temperature will read about 204°F when measured with a digital thermometer.

Step 12

, Remove the loaf from the oven and turn it out of the pan onto a rack to cool completely before slicing.

Step 13

, Store the bread, well wrapped, at room temperature for 4 to 5 days; freeze for longer storage.