The night before you're going to bake, make the levain: Weigh the spelt flour, or measure it by gently spooning it into a measuring cup and sweeping off the excess. Mix the spelt flour, water, and starter together, cover, and set aside at room temperature for 12 hours, or overnight. At this time the levain should be expanded and very bubbly, but not yet starting to fall., The next day, weigh the flours, or measure them by gently spooning them into a measuring cup and sweeping off the excess. Combine the flours with all the levain, and the remaining dough ingredients., Mix and knead everything together — by hand, mixer, or bread machine set on the dough cycle — until you have a soft, smooth, elastic dough, incorporating only as much of the remaining 1/2 cup of all-purpose flour as you need to keep the dough from sticking; it will quickly become smooth and elastic., Let the dough rise, covered, for about 1 hour. It won't double in that time, but it will start to get puffy., Meanwhile, grease a covered bread loaf baker., After an hour, remove the dough from the bowl and form it into a 9" log. Place the loaf in the baker, cover it with the baker's lid, and let it rise for 1 to 1 1/2 hours., About 30 minutes before you're ready to bake, preheat your oven to 425°F., Remove the lid of the baker, and slash the loaf lengthwise down the center; dusting the loaf lightly with flour will help you make a neater slash and gives the finished loaf a nice artisan look. Place the cover back on the baker., Bake the bread for 10 minutes, then reduce the oven temperature to 400°F and bake for 25 to 30 minutes longer. Remove the lid, and bake for another 5 minutes or so, until the loaf is nicely golden; a digital thermometer inserted into the center of the loaf should read 190°F., Remove the bread from the oven, turn it out of the baker immediately, and cool it thoroughly before slicing., Store bread at room temperature, well wrapped, for several days. Freeze for longer storage.