Notes on coarse-ground brown rice and buckwheat. 
Coarse grinding produces a flour with rich grain flavor and the ability to create enhanced dough bubbles. Using long-grain brown rice - NOT par boiled - measure about 1 cup into a spice or coffee grinder. Run the grinder for 20 seconds, then shake vigorously, then whir and shake again 3 more times. Check to be certain there are no unbroken grains. You may need to work in two batches if your grinder is small. Store flour in a zip lock bag, measuring out the amount needed for starter-awakening, pre-dough creation, and the tangzhong as you perform each step. For the buckwheat, use 1/2 cup buckwheat groats but whir and shake just half as often. Buckwheat is a much softer grain.

Procedure:

Day One:  Awaken starter. Place sleeping starter, 1/8 cup of the coarse brown rice flour, and 20 Ml of the water into a small plastic snap-lid container or a glass jar. Stir well and loosely fasten cap. Set in a 75 - 80 F place and allow to rest for 4 hours, then add the remainder of the coarse brown rice flour and the water and return to resting 6 more hours. Cover tightly and remove to refrigerator. (See photo 1)

Day Two: Make pre-dough. Place the coarse brown rice flour, the oat flour, the steel-cut oats, the buckwheat flour, 15 grams of the previous day's awakened starter, and the water into a small snap-top plastic container. Stir until thoroughly blended. Cover and set in a 75 - 80 F place and allow to rest 7 hours, then cover tightly and remove to refrigerator. (see photo 2) Reserve the remainder of the awakened starter in the refrigerator.

Day Three: Make and bake dough.

1) Make a tangzhong by mixing coarse brown rice flour, milk and water in a small sauce pan. Stir lightly over medium heat until mixture thickens to the consistency of custard. Remove to a small bowl to cool, and clean saucepan immediately to prevent sticking.

2) As tangzhong cools, prepare the loaf pan by greasing with butter or a vegan margarine and dusting with fine flour, such as oat.

3) Place all the dry loaf ingredients in the bowl of a stand mixer and run the mixer on low speed until the ingredients are well-blended, about 2 minutes. Add the pre-dough, the tangzhong, and the water and mix on medium speed until dough is thoroughly wetted. Let dough rest for 5 minutes, then beat on high medium, until dough just begins to loosen and liquify. Reserve unused pre-dough and tangzhong to the refrigerator. 

4) Using bowl scraper or spatula, scrape down along the edge of the bowl, loosening the dough and turning it in towards the center. When all dough is scraped into the center of the bowl bottom, turn dough out in a single unit into the prepared bread pan. Use a wet spatula to press dough down and work into corners, (see photo 3) taking care to not press out any captured air. Smooth the top of the dough, cover loosely with a towel, and set in a dark warm place (75 - 80 F) for 9 hours. Dough will rise but not quite double in size. (see photo 4).

5) Heat oven to 425 F. DO NOT use "fan" or "convection" setting. Lightly spritz the top of the loaf. Make a double-layered covering out of parchment  - one long narrow strip and one shorter, wide strip - and lay both loosely across the dough, one atop the other. (see photo 5) Place "tented" pan into oven on a middle rack and bake 90 minutes. Loaf will vigorously "spring". (see photo 6). Remove to a cooling rack and allow to cool at least 2 hours, or preferable overnight. Cut and enjoy! (see photo 7).

To store: Place loaf cut-side-down on a clean surface. Do not cover. Do not refrigerate. Loaf may be wrapped and frozen.