With my daughter that's gluten sensitive back from college, I decided to see if I could come up with a sourdough GF loaf.
I started by creating a brown rice starter. I cheated though and used scrapings from my AP/WW starter. My first mix was the scrapings left over from a refresh of the AP/WW. Best guess is there was less than 1 gram left in the jar. To that, I added 25g of brown rice flour and 25g of water. After 24 hours, it was quite bubbly and showing at least 50% expansion. So far for me, the rice starter doesn't go much beyond that for expansion no matter how long I leave it. Subsequent feedings were 1:5 (water:flour) at 90% hydration. After the 4th feeding, the wheat flour in the starter was below the limit for a 1kg loaf to be determined GF. On all subsequent refreshes, the mature starter has a wonderful aroma that's somewhere between fruity and buttery. It is a sweet smell that doesn't remind me of sour at all.
This recipe uses two GF flour blends. Why... I had both brands in the pantry and wanted to use up one before opening the other the first time I tried it. Had reasonable success and didn't want to mess with it. :-) The hardest part is getting the consistency right. My guess is this will work just fine with other GF flour blend brands. You'll just have to play with the hydration until you get that heavy cake/brownie batter consistency.
I'm not sure how long you can safely ferment a dough with egg whites in it, so I've been adding a bit of ADY to the final mix to make sure the final proof moves along. I't been getting done in 2-3 hours. Need to do some digging to see if the ADY can be dropped further and extend ferment/proofing out to 3-4 hours.
142.5g Domata 1-for-1 GF flour blend
20g brown rice flour starter culture
Ferment 12-16 hours at 70-72 deg F
285g KAF GF flour blend
47.5g Bob's Red Mill GF Oat Flour
9.5g Pink Himalayan Salt
26.1g Salted Butter (room temp)
60-65g Egg Whites (2 large eggs) (room temp)
1.2g Active Dry Yeast
Combine final fours and salt then mix with a whisk
Rub room temperature butter into the fours using a fork until butter is evenly distributed. (Flour will get something like a coarse sand look to it.)
Combine final water and honey. Warm to 80-85 deg F and then activate the ADY in that mixture. Set aside for 5-10 minutes to let ADY wake up.
Whip room temp egg whites slightly until they get a little aerated and bubbly on top. I haven't been going all the way to fully whipped.
Create a well in the center of the flour/butter blend.
Add activated ADY/water/honey mixture to the levain and mix thoroughly. Pour mixture into well and add whipped egg whites. Slowly stir mixture with a spoon and gradually incorporate flour to it. Thoroughly mix and make sure any lumps are broken and batter is smooth It should have the consistency of a very heavy cake or brownie batter.
Spoon batter into a buttered/GF floured loaf pan and smooth top with a wetted spatula.
Put loaf pan in a sealed bag (I use a large clear plastic bread bag I got from Amazon) and put in final proof at 81 deg F. Let rise until center of the loaf is approximately 1" above the pan rim.
Approximately 30 mins prior to final proof finishing, pre-heat oven to 350 deg.
When dough has finished rising, GENTLY spread melted butter on top of loaf. (I use a silicone bristle BBQ brush)
Oven set-up: Cookie sheet on very top rack shielding upper element. Cookie sheet on very bottom rack shielding bottom element. Pizza stone on rack one slot above bottom rack.
Bake for 30 minutes at 350 deg F with steam (I put in GW roaster pan) and then 30 minutes without steam. After the 60 minutes, I remove the loaf from the pan and place it directly on the baking stone for another 15 minutes. Final internal temp is usually about 210 deg F.
Turn off oven and leave loaf in the oven with the door cracked for another 10 minutes. Let loaf fully cool on a wire rack at room temp before putting in a bag.
Levain/Water/Honey/ADY/Egg Whites combined in flour well before mixing
After removing lid. Good oven spring!