Purple sweet potato sourdough sandwich loaf

Purple sweet potato sourdough sandwich loaf

I really am in love with Stokes purple sweet potatoes. I’ve used them to make sweet potato latkes. And this week I made mashed purple sweet potatoes and banana. There was one baked sweet potato leftover from that night, so I used it for this purple sweet potato sourdough sandwich loaf.

I’ve previously made another sweet potato sourdough that is a variation of my cheater sourdough (i.e. it uses a bit of commercial yeast). That one has bacon. Yes, bacon. This purple sourdough sandwich loaf is not as decadent, and it’s much prettier.

a cutting board with a cut purple sweet potato, a whole potato, and a knife
three purple sweet potatoes on foil with one sliced open to show the purple flesh

A few notes

– The amount of water or flour you will need will vary based on your levain (I use a 100% starter – equal amounts of water and flour – in a small volume levain), your sweet potato, etc. Please don’t think of my amounts as law. You want to end up with a sticky ball of dough at the end of mixing.
– I bake bread in order to have an easy-to-slice loaf of bread for sandwiches. But you can shape this in any way that makes you happy. I’m jealous of all of those pretty boules out there.

a mixing bowl with the bread mixture which has not yet come together
a mixing bowl with a pinkish purplish ball of bread dough

Frequently asked questions about purple sweet potato sourdough

Why do you use yeast in your sourdough bread?

I make a cheater’s sourdough using 1/4-1/2 tsp of instant yeast so that I can finish the loaf in one day. Feel free to omit the commercial yeast if you are a purist.

Why do you add salt after all the other ingredients?

I have acquired the belief, true or not, that you shouldn’t add salt to bread until well after the process has started for fear of direct salt effect on the yeast and bacteria (that whole osmosis and cell wall thing). This is probably overkill, but it is something I always do (i.e. delay adding salt).

What is that loaf pan you use?

It is the Italian Bread Loaf pan from Emile Henry.

Can I substitute other sweet potatoes for the purple sweet potatoes?

Yes, and please see my note above re: water and flour. Purple sweet potatoes are slightly drier than white- and orange-fleshed sweet potatoes, so you might need to adjust.

Are these purple sweet potatoes the same as yams?

I wrote a few sentences a week or so ago to answer this question about the difference between purple sweet potatoes and purple yams (ube). Spoiler: the only thing they share in common is their color!

Can you freeze this bread?

Yes. If we are not going to eat the loaf within a few days, I slice the bread and put the slices in a freezer bag in the freezer to extend the life of the loaf.

What do you make with your sourdough discard?

The King Arthur website has a great list of sourdough discard recipes. The crackers have been my favorite so far.

a ceramic loaf pan with a pinkish purplish loaf of purple sweet potato sourdough ready to rise

Purple sweet potato sourdough

Author uglyducklingbakery


  • 1 cup mashed purple sweet potato
  • 1 cup (125g) whole wheat flour
  • 3 cup (375g) bread flour plus more as necessary
  • ¼ tsp instant yeast optional
  • 127 g levain (sourdough starter)
  • 1 cup (250g) lukewarm water plus more as necessary
  • 2 tbsp maple syrup
  • 1 tsp salt
  • butter or oil for greasing, if using a loaf pan


  • In a large bowl, mix the sweet potato, flours, yeast (if using), levain/starter, water, and maple syrup, initially with a spoon or spatula and then by hand. The mixture should be somewhat sticky, so add small amounts of flour or water as needed. Cover with plastic wrap and set aside for 20-30 minutes.
  • Add the to the bowl and knead until incorporated. Form into a ball and lightly oil the bowl. Cover with plastic wrap and put in a warm location – the microwave or a 85-90°F oven works well here.
  • Every 20-30 minutes for 2-3 hours, reshape the dough into a ball. Do not stress if it's shorter or longer than 20-30 min intervals. Because of the stickiness, you might need to wet your hands for the first one or two of these. It should double in size and get more pliable.
  • Shape and let rise in a greased bread loaf baker or dutch oven. I really love my bread loaf baker, which gives a great crust and that loaf shape that I need. Let it rise until doubled in size – how long will depend on whether you were using a well-fed or un-fed starter and/or the amount of commercial yeast.
  • Preheat the oven to 450°F at least one hour before baking.
  • Bake at 450°F in the dutch oven/baker for 30 min, then reduce the heat to 350°F, remove the lid and bake about another 15 minutes. When done, the internal temperature of the loaf should be 190-195°F, and it will sound hollow when the bottom of the loaf is thumped.
  • Let cool for at least one hour before cutting.

What’s next?

If you make this purple sweet potato sourdough, please comment and/or share a pic!

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a turkey,cheese, and avocado sandwich on pink bread with 4 strawberries on a plate

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