I've been wanting to make a purple sweet potato loaf for a while now because purple sweet potato is my favorite kind of potato. In this bread, I used a TON of potato puree and a lot of cornmeal, and it gave me a really beautiful loaf. The oven spring on this loaf was amazing, but the crumb is dense and cake-like. The purple sweet potato gives off a really nice floral taste and the texture of the crumb is almost creamy. Tastes even nicer the next day.
I cut into while it was still a little hot, which disturbed the crumb pattern in this picture, but look at this color!
400g bread flour
150g blue cornmeal
50g wholewheat flour
350g mashed purple sweet potato*
120g starter (I used 100% rye at 80% hydration)
*the texture of purple sweet potatoes really varies from potato to potato. Some are starchy and crumbly/dry on the inside where they're cooked, and some are soft and a bit more moist. The large sweet potato I used happened to be very dry, so when I mashed it had the texture of wet sand almost so in my baker's percentage, I counted it as a dry ingredient, which is why I have so much water listed in the recipe. My original notes called for 420g water but when I made the dough it was SO dry I had to add an extra 160g water.
I put 200g of the sweet potato in the blender with 420g of the water, and added it to the flour during the autolyse stage. Then I added the remaining 150g in after two stretch and folds so that little lumps of potato would be running through the loaf.
This dough was a little difficult to work with and shape because of the relatively low gluten content (lots of potato, lots of cornmeal), but I loved making this loaf because of how beautiful all the colors were.
*Edited: Decided to add some extra steps that I think were important to this bake!
1) Mix together water, flour, half of the cornmeal, and blended potato mixture mentioned above. Set aside for about an hour.
2) Add the starter and do slap and folds for about five minutes. Because of the little amount of gluten, during the mixing stage, the dough became very loose and slimy. Usually if a dough is super wet after slap and fold, it pulls itself back together if I let it sit for a few minutes to reabsorb, but this dough didn't do that as much, however, after a few stretch and folds over the course of four hours, it became firm enough to handle. I don't have a video for this specific dough, but on my channel, there is a video for a Carrot Sourdough which was about as wet as this one (also because of the disrupted gluten formation), and in that video, i demonstrate basically how I dealt with this dough and how I shaped it.
3) Place the dough into a clean bowl and rest for thirty minutes before mixing in the salt and the remaining cornmeal.
4) After 45 minutes, begin with stretch and folds over the coarse of three and a half hours. Before the 2nd stretch and fold, mix in the remaining mashed sweet potato. I did 1 stretch and fold every 45 minutes. By the third fold, the dough had nearly doubled, and it was relatively cold in my kitchen, so like any dough, keep your eye on the dough and not the clock.
5) Pre-round the dough and let sit on the counter uncovered for 20 minutes. Dust with flour (I used coarse rye) and shape tightly. Place in a banneton and let proof. This loaf only needed about an hour and a half before it was ready. Since it was proofed before I was ready, I popped the banneton in the freezer for twenty minutes to give my oven some extra time to heat up.
6) score and bake at 500F covered/steamed for 22 minutes then bring the temperature down to 450F and bake uncovered for 25 minutes. Let cool completely, maybe even wait till the next day before cutting into it.
Good luck and enjoy!