Purple Sweet Potato Soft Sourdough Bread

by - August 06, 2019

Whenever my step-daughter is back for her summer holidays, she will ask for the purple sweet potato bread.  I used to bake this for her using commercial yeast but this time I modified the recipe using sourdough starter.

Characteristic of this bread:  The texture is especially soft, fluffy and moist on the first day and it lasts very well for 2 - 3 days.  The crumb is slightly bigger probably because of the sweet potato. I couldn't taste any sourness of the sourdough.

If you have any questions regarding this recipe or any other post, please leave me a comment in the “LEAVE A COMMENT” link and I will reply you as soon as possible.

Purple Sweet Potato Soft Sourdough Bread Recipe

Yields:  1 loaf


Levain - 165g total (ratio 1:3:3):
24g sourdough starter (100% Hydration)
72 bread flour
72g water

Main Dough:
400g bread flour (I used high gluten Japanese Bread Flour)
250g mashed purple sweet potato (about 300g purple sweet potato - peeled, cut, steamed and mashed)
35g brown sugar (I used organic brown sugar)
1 1/4 tsp salt
50g butter
80g - 100g full cream milk (Add 80g first then add 1 tbsp at a time if too dry)

Egg Wash:
1 egg, whisked + 1 tbsp water 

600g loaf pan (12" X 3.5" X 4"  or  31cm X 9cm X 10cm)


  1. One night before baking, mix all ingredients in a jar and cover.
  2. Let it ferment at room temperature (approximately 27-28C) overnight until tripled.  It took about 12 hours. The total weight should be around 165g.
Note:  If you like to prepare the levain on the same baking day, please use the ratio 1:1:1.  Let it ferment at room temperature (approximately 30C) until tripled.  It took about 3-5 hours depend how strong is your starter.

Main Dough:
  1. Put all ingredients, including the 165g sourdough starter (levain) into the bowl of stand mixer. Using the dough hook, knead for 10 - 15 minutes (Chef Kenwood mixer, speed 2.5) until the dough comes together and window pane stage.
  2. Let the dough rise in a warm place for 60 minutes in a large greased bowl, covered with cling film or kitchen towel.  It is fine if the dough doesn't rise until double the size after 1 hour.
To shape:
  1. Punch down the dough to release the air. Transfer the dough to a clean floured surface then divide into 3 equal portions. 
  2. Form each portion to a ball.  Flatten with rolling pin into a dish.  
  3. Fold right to centre and fold left overlap it.  Roll out with rolling pin into long rectangle shape. Roll up the dough like Swiss Roll until a small log is formed. 
  4. Place all dough in the prepared loaf pan.  Let it proof at warm and dark place until the dough is double in size (This one took approximately 4 hours). 
Note: To speed up the rising process, place the dough in the oven and a bowl of hot water next to it and close the oven door.

To bake:
  1. Fifteen minutes before baking, preheat the oven to 180C.
  2. Brush with egg wash.
  3. Bake at preheated oven for 30 minutes, or until golden brown.
  4. Remove bread from oven and let it cool on rack completely before slicing.

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  1. Hi, tried this purple potatoes recipe, outcome was great, thanks for sharing the recipe. One question is, should this bread still taste a little sour, it.is because use of levain I suppose?

    1. Hi, sorry for late response. Thank you for trying this recipe and feedback. Yes, the sourness is from the levain (sourdough starter). Mine was very mild and couldn't really taste it.

      Cheers :)

  2. hello, your recipe looks so good and i would really like to try it! if i use a 1:1:1 ratio for the levain, does that mean i can use 60g of each to make a total of 180g of levain, then use only 165g for the actual dough? also, is it possible to bake this as a whole loaf (like a normal sourdough shaped in a banneton)? thank you!

    1. Hi there,

      Thank you for asking. Yes, you are right use 60g each to yield 180g of levain and use only 165g. I never tried to shape soft bread dough in a banneton. You can try. I am curious too :)

      Cheers :)

  3. Your recipes looks beautiful. Do you have any sourdough doughnut recipe to try? Thank in advance :)

    1. Hi there,

      Sorry for late response. I have not tried sourdough doughnut yet. I will try and share the recipe if successful.

      Thank you for your comment and compliment.

      Cheers :)