Purple Sweet Potato Sourdough

I get on weird kicks every now and then and currently it’s trying to make purple bread. If you asked me why, I honestly have no answer for you. Before I started baking my own bread, I’d often find myself buying potato bread due to its soft texture. This bread has that same pillowy and moist feeling but some added sweetness from the sweet potato. Oh yeah, and it’s purple!

Purple sweet potato sourdough

Schedule: I based this loaf off of my hybrid schedule.

Since this uses a big portion of natural yeast to ferment, I created a levain with my sourdough starter that was last fed 12 hours prior. This levain provides enough for this bread, plus extra to keep your starter going. The small amount of bakers yeast helps give a little boost to the rising of the bread.

Due to the moistness of the sweet potato mash, I didn’t add nearly as much water as I normally would. After a few failed experiments I realized that the dough was extremely wet and wasn’t holding its structure at all.

30 minutes before mixing the bakers yeast and salt into the dough, I performed an autolyse by mixing the potato mash, water, levain and flour together.



Started at 7:30am with the following ingredients. Mix everything together and loosely cover and let it ferment for about 8 hours.

  • 28g unfed sourdough starter (last feeding was 12 hours prior)
  • 138g filtered water @ 85-90’F
  • 110g bread flour
  • 28g King Arthur whole wheat flour


  • 490g bread flour
  • 30g dark rye flour
  • 308g filtered water @ 90-95’F
  • 180g levain
  • 12g sea salt
  • 1/4 tsp yeast
  • 150g purple sweet potato mash (see below)
Purple sweet potato


The first thing you’ll need to do is prep your sweet potato mash. I did this by poking some holes in the potato with a fork and baking at 350’F for about an hour and a half, or until the potato was a little mushy when I poked it. You can microwave it, but the long low-and-slow baking really helps convert those starches into sugars and really boosts the complexity of the flavors.

After the potato cools slightly, peel the skin off and mash the potato with a fork. Measure out 150g for the bread and then you can use the rest to make purple mashed sweet potatoes (note, it looks just like purple playdough, but whatever, it still tastes great with a little butter and salt).

Cooked purple sweet potato

Allow the potato mash to cool to room temperature before using it in your bread. I added the mash, flour, water and levain to a stand mixer and mixed / kneaded it for about 5 minutes with the dough hook attachment and then gave it a 30 minute autolyse before adding my salt and yeast.

After mixing in the salt and yeast, I performed 4 stretch and folds within the first 2 hours. The dough bulk fermented at room temperature for about 5 hours.

I proofed the dough overnight in the refrigerator in a banneton which was wrapped in a plastic bag.

The next morning I woke up, preheated the oven and then I baked the loaf in a preheated dutch oven at 450’F for 38 minutes covered, then removed the lid of the dutch oven and baked for an additional 14 minutes.

Getting ready to mix the potato and flour
The mixed purple sweet potato dough


The dough proofed extremely well in the refrigerator overnight. This equated to a really nice oven spring and natural venting in the crust of the bread. I didn’t quite center it in my dutch oven so the loaf itself is a little oblong.

The color of the crust is mostly brown with some hints of purple coming through the parts of the crust that broke open during baking. The crumb is rather compact (not surprising since you’re basically adding mashed potatoes to the bread) and ended up with a color somewhere between pink and purple.

When eating it, the sweetness of the potato comes through well. It has the typical qualities of a potato bread that I look for: moistness, fluffy / soft texture and smooth mouthfeel.

Purple sweet potato sourdough
Blisters formed from the long overnight proofing
Natural venting with some purple color visible

Thoughts for next time:

The first time I baked bread with walnuts, I immediately thought the walnuts contributed a little bit of purple coloration. In an effort to make this bread as purple as possible I’ll try adding 80-100g of roughly chopped walnuts to the loaf.

I was considering adding more purple sweet potato mash but I think 150g is pushing the limits for a loaf of this size. When I was mixing the dough I already had to add more flour (which I accounted for in the ingredients above). Before an additional 80g of bread flour, this dough was extremely wet and unworkable.

Another option to boost the color would be to use some blue cornmeal. I’m hesitant to do this, however, since the rough texture of the cornmeal goes against the light and fluffy texture i’m looking for by adding the potato.

My Baking Notes

  • Ambient temperature: 70’F
  • Started autolyse @ 3:00pm
  • Water temp: 92’F
  • Dough was 86’F at autolyse
  • Mixed @ 3:35pm
  • Dough was 80’F after mixing
  • 4 stretch and folds in first 2 hours
  • Started proof @ 8:15pm
  • Preheated oven @ 6:00am the next morning
  • Into oven @ 6:50am
Purple sweet potato sourdough top view

3 Comments Add yours

  1. IngioMontoya420 says:

    This is amazing! Are you on YouTube? Hi from Reddit


    1. alegrebread says:

      Hey! Not yet but it’s something I plan on doing eventually šŸ™‚


Leave a Reply

Fill in your details below or click an icon to log in:

WordPress.com Logo

You are commenting using your WordPress.com account. Log Out /  Change )

Twitter picture

You are commenting using your Twitter account. Log Out /  Change )

Facebook photo

You are commenting using your Facebook account. Log Out /  Change )

Connecting to %s