Tuesday, May 20, 2014

Sweet Potato Burger Buns: Sourdough Surprises May

I think this may be the third time that I am using sweet potatoes in a recipe for Sourdough Surprises. I do like sweet potatoes, but even I am surprised at how often I think of it when deciding on a recipe. I think it's the colour that draws me in. But let's not get too caught up on that. Let's talk about these sweet potato buns.

I did some extra research when I was planning these buns. Sure, I scoured the internet as usual. But this time I went to the supermarket and touched all the unbelievably soft hamburger and hot dog buns. Sorry, customers who came after me. I promise that I did not manhandle your buns. (That sounds kinda wrong.) I also read the ingredients. I wanted soft buns! Almost all the buns had vital wheat gluten and vinegar. Vinegar was a strange one. It seems vinegar strengthens gluten but inhibits yeast. Tricky. I added it here but honestly, I don't think it made a difference or was necessary. My buns had a long rise, gluten formation was not an issue. I think I will try vinegar again in something with high hydration. .

Potatoes are supposed to soften the dough. But it occurred to me that I did not know if sweet potatoes acted in the same way as white potatoes. And what proportion of potatoes to flour would be best? This simply means that I have rounds 2 et al. in the works.

Fair warning: This recipe makes a lot of dough - almost three pounds. For my next trial, I will use a stiff starter and less flour. That will give the potatoes a chance to show me just how much they really enhance the dough.

Now, all of this does NOT mean that I was disappointed with my buns. Not in the slightest. They were not grocery store soft but the crumb was still soft and very much delicious. In fact, the firmer crusts here, actually made these buns more sturdy and more perfect for fillings like sloppy joes. You can do an overnight bulk proof for a stronger sourdough flavour or if you simply run out of time to shape and bake your rolls (*ahem*).

Sweet Potato Sourdough Burger Buns


6.25 oz all purpose flour 
9 oz mature sourdough starter 166%
3 oz milk 

Final Dough
8.25 oz mashed sweet potato (~1 cup)
3 oz water
1 oz oil
2 egg yolks
1 tablespoon sugar
13 oz flour
0.6 oz vital wheat gluten (1 1/2 tablespoons)
0.3 oz salt
1 tsp vinegar (optional)
egg whites for brushing dough


Combine the sponge ingredients and leave overnight.

Combine the sponge, mashed potatoes, water, oil, egg yolks and sugar in a mixing bowl until thoroughly combined. And the flour and vital wheat gluten and knead for 3 minutes. Allow to rest for 20 minutes then add salt and vinegar (if using). Knead in a stand mixer for 5 - 7 mins. Leave to rise until doubled (~6 hours). Dough can be refrigerated before moving onto the next step. 

Divide the dough into 16 equal pieces ( ~ 3 oz each) and shape each piece into a tight ball. Allow to rest for an hour then flatten slightly. Let rise until doubled. 

Preheat oven to 425 F. 

Gently brush the tops of each bun with egg whites. Bake for 15 minutes.


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