85% Hydration No-Water-Added SD Sweet Potato Milk Loaf

I've been developing this formula for weeks, and I was testing the possibility of adding more sweet potatoes into my loaves. I didn't plan to post it, but thanks to our brief discussion with Debra, I decided to post it.

Steamed sweet potatoes were used to make this loaf. They hold water really well (duh, they literally were born with the water), handling 85% hydration dough felt like handling 75% hydration regular tangzhong dough. You may say this is tangzhong on steroid.

For every 570 grams of flour (starter, dry matter of sweet potatoes, and vital wheat gluten are considered as flour), the formula fits two 12x12x12 cm pullman pans. Proof until the top of the dough 2 mm close to the pan's cover, nearly touching it. I lined the four pans (I made four, which means 1140 grams of flour were used) with parchment paper, including the covers (I rubbed the inner part of the covers with oil to make the pieces of paper adhered to the covers)

I put sugar and skim milk powder in the levain to increase osmotic pressure. For maximum fluffiness, a little instant yeast was used for stronger final proof (took 2 hours). Vital wheat gluten was used to make dough equivalent to 12% wheat protein dough, assuming vital wheat gluten is 75% protein.

Vital wheat gluten, sweet potato dry matter, and starter are consider flour, percentages of the rest of ingredients are written in baker's percentage. I assumed sweet potatoes are 79% water.

I cooled the baked loaves down leaning on their sides so they won't lose their height. If you feel like trying, do not use dusting flour during shaping, otherwise you'll have streaky crumb. Use water spray instead.

I gave wiggle room for the amount of sugar, 7-10%, depending on the sweet potatoes. It's important to taste the potatoes before using.

Adjust your upper burner temperature to your usual setup. My oven bakes more evenly when the upper burner is 70 °C hotter then the lower burner.

Summary

pureed steamed sweet potatoes (20% as dry matter), 20% prefermented flour, 10% butter, 10% brown sugar, overnight levain, fine-bran starter (bran:sugar:water 8:1:3, 0.5% baker's percentage), 3.5% vital wheat gluten, 1.5% salt, 8.8% egg, 8.8% skim milk powder, 1/2 tsp instant yeast /570g of flour, cold bulk, 14% protein white flour, sugared autolyse, windowpane, deck oven, spiral mixer, 250 °C upper & 180 °C lower

Taste and Verdict

The bread is slightly sweet, with honey-like flavor from the potatoes. Ohh, and the texture. Sooo fluffy, so cottony. The bread will make good grilled cheese. Since I need to keep on improving the formula, the bread is naturally part of my daily bread rotation.

Next trial, I will bump up the sweet potatoes to 29% dry matter, resulting in 116% dough hydration. I will do three stages levain next time, since I was short in time for these ones.

Jay