My 6th bread baking lesson - multigrain sandwich bread

The potato rosemary bread has been a real great success for the whole week. Now we are moving on to more grains! This time the experiment is a multigrain sandwich bread, with a mix of unbleached flour and whole wheat flour.

Recipe: Multigrain sandwich bread (adapted from Peter Reinhart's whole grains recipe, make 1 large loaf)

Ingredients:
soaker
- 7 tablespoons (TB) whole wheat flour
- 1+1/3 cup combination of cooked wheat berries, wild rice, steel cut hot cereal grains (oat/barley/wheat)
- 1/2 TB oat bran
- 3.5 TB buttermilk powder
- 5/12 cup water
biga
- 1+3/4 cups unbleached grocery store brand all purpose flour
- 3/8 teaspoon (tp) active dry yeast
- 1/2 cup + 2 TB tap water
final dough
- all the soaker
- all the biga
- 8 TB whole wheat flour
- 5/8 tp salt
- 3 tp active dry yeast
- 2+1/4 TB honey
- 1 TB olive oil

Procedure:
Day 1

1. Mix all of the biga ingredients together in a bowl to form a dough. Use a spoon to stir and knead for 5-10 minutes. Wrap bowl tightly with plastic wrap, and refrigerate for at least 8 hours.
2. To prepare the cooked grains, boil the wheat berries and wild rice separately in water until they open up. Remove the grains from the liquid. The water can be reused to cook the cereal grains, which takes much shorter time to cook. Mix the grains together with oat bran to form a thick porridge. Allow to cool to room temperature.
3. Mix the powder ingredients of the soaker (whole wheat flour, salt, buttermilk powder) in a bowl. Add in the cooked grains and mix. Add about 5/12 cup of water to allow the powder to dissolve into the porridge-like mix. (If necessary, add up to 3/4 cup + 2 TB water.) Cover loosely with plastic wrap and allow to rest on the counter at room temperature (about 70-72F) for 12-24 hours.

Day 2

1. Mix all the dry ingredients of the final dough (flour, salt, yeast) in a large bowl. Stir in the biga and the soaker in small batches. Then add the oil and the honey. Stir until the ingredients are fully incorporated. Continue to stir for 5-10 minutes to allow the dough to develop some strength.
2. Pour into a greased bowl and allow to rise until it is 1.5 times its original volume.
3. Pour into a greased 4"x8" loaf pan. Sprinkle oat bran as toppings. Allow the dough to rest. It's volume will increase again by 1.5 times. 
4. Preheat oven to 450F. Sprinkle water on top of the loaf (if necessary). Then place loaf pan in oven. Bake for 20 minutes at 300F. Then rotate the loaf by 180 degrees and bake for another 20-30 minutes.
5. Cool on a rake for at least 1 hour before serving.

Results:

Day 1
10:07pm, biga mixed with just 1/2 cup and 1 TB water

10:13pm, biga mixed with one additional 1 TB of water

10:21pm, soaker grains being cooked

10:39pm, soaker and biga prepared

10:39pm, biga texture before putting into the fridge:

10:39pm, soaker texture before setting on the counter overnight:

Day 2
8:30am, look of the biga and the soaker after one night:

3:39pm, look of the biga (after warming up to room temperature for 2 hours) and the soaker:

4:06pm, texture of the soaker:

4:07pm, texture of the biga:

4:23pm, the final dough when it's initially mixed is very watery. Additional flour is needed to increase the cohesiveness of the dough. (Peter Reinhart's original recipe only called for 3.5 TB, I used 8 TB.)

4:39pm, after using 8 TB of flour in the final dough, the dough remains watery. So no further addition is made. Dough is set to rise in a greased bowl in an oven preheated to 150F.

5:02pm, dough rises rapidly after being in oven of 150F for 20 minutes:

5:04pm, dough punched down:

5:11pm, dough set in loaf pan to rest in oven at 150F:

5:11pm, dough's initial height when set in loaf pan:

5:19pm, dough after resting for 8 minutes in oven at 150F:

5:20pm, dough risen so much that it's punched down by a fork again:

5:22pm, oat bran added:

5:36pm, dough rising again after the 2nd resting of 14 minutes in oven at 150F:

5:43pm, dough scored:

5:43pm, height of dough just before baking (there is already a mild shrinkage of the dough after coming out of the 150F oven to room temperature counter):

5:43pm, dough placed in oven preheated to 450F (oven set to 350F once baking starts)

6:08pm, loaf after 20 minutes of baking:

6:27pm, loaf freshly out of oven after 50 minutes of baking (last 10 minutes is baked with foil to cover the top to prevent further browning):

6:38pm, side of the freshly baked loaf:

6:39pm, bottom of the freshly baked loaf:

7:30pm, top of the loaf after 50 minutes of cooling:

7:32pm, this loaf is so moist that it sticks to the knife:

7:40pm, 18 slices yielded:

7:40pm, look of a center-of-loaf slice (observe that there is an indentation underneath the scored top:

7:40pm, loof of an end-of-loaf slice:

Observations:

1. This time, I've noticed that my biga is a bit more watery than before, even though I followed Peter Reinhart's recipe. I should have used 1 TB water less.
2. The soaker is overly watery, because of the amount of water contained in the cooked grains. 
3. The over-hydration of this dough causes it not to be able to develop enough gluten. So the loaf is not able to sustain its risen height during baking. As a result, the top of the loaf is totally flat when it's baked.
4. There are still sufficient amount of holes of comfortable sizes in the crumbs. In fact, some of the holes are rather large too.
5. Even though it's been baked for 50 minutes (10 extra minutes compared to previous experiments), the loaf is still a little too moist. It is sticky to the knife. 
6. This loaf has a mildly sweet taste. The grains are soft but noticeable. I prefer the salty, nutty and herb taste of the potato rosemary wild rice bread in the previous experiment. But this loaf makes a good sandwich bread.

Conclusion:
This loaf is satisfactory. In my next experiment, I'll try some drier versions of the breads.