Roasted Potato & Rosemary Bread

My first attempt at a potato sourdough was using boiled potato with some of its cooking water in the dough to a disastrous effect.  You can see the photos below, destroyed the gluten development and like the post I wrote on over-proving dough, I had a lifeless dough in my hands.  I tried it twice, second time using autolyse but still it didn’t work, I think I was adding too much potato.  I left it for a while and came back when coming across Jeffrey’s Hamelman’s Roasted Potato Bread  recipe at the time I was using his book for my experience in the cafe.  I was attracted by the idea of roasting the potatoes and liked what he wrote in his notes about it.

I’ve change Geoffrey’s yeast recipe to a sourdough, rounded off the measurements to the nearest grams, have added rosemary and as you can see have made this bread a few times now, every time I’ve had good results.  It’s a very popular bread except with Bikerboy who doesn’t like rosemary in bread…so we’ve discovered.

Potato does something quite wonderful to bread, something I’ve already experience with in my regular yeast toast loaf for allergy kid, where I add potato flour.  It softens the crumb and gives you the most wonderful toast.  There’s something about the browning of bread containing potato that’s quite magical, giving you a very crunchy toast.  Someone did say to me there was a maillard reaction going on there.

What I’ve discovered with the levain is potato gives an openness and airiness to the crumb, much more noticeable than without.  It will again give good crunchy toast but then sourdough makes good toast anyway.  The first thought that occurs to me with the effect is maybe the potato is supplying food (sugar) to the levain/enzymes and therefore producing nice big airy gas bubbles.

The potato loaves below were made without the rosemary and I think it was my very first attempt at making the loaf, they were left after shaping proving on a baking sheet on the dinning room table overnight (8hrs) at room temperature of 10C / 50F degrees.  It came to no harm but grew enormously as you can see taking the side shape of the baking tin.

The crumb is so light and airy.

The disastrous looking dough below is my failed attempt at adding boiled potato and its water to the dough, collapsing the gluten strands.

Roasted Potato & Rosemary Sourdough

Makes 2 large loaves


I peel and slice the potatoes into thick wedges, sprinkle little olive oil over them and tiny bit of sea salt and bake until they’re cooked.  I do this hours or the day before baking.  I use red skinned potatoes because they don’t collapse completely when baked which means when folding into the dough not all of it will be mashed, some will remain in pieces.  Geoffrey leaves the skin on in his recipe so feel free to the same.  I don’t remember how much of raw potato I use to get this cooked amount but bear in mind potatoes lose a lot of moisture during baking and you need more than you think.  I would allow for double if you have leftovers snack on it!

Flour & Water – I use 12% protein white flour, if your flour is higher protein and a dryer flour you may want to add a bit more water.   But regardless of that be beware this dough will still feel slightly drier than my usual wet doughs.   This dough works out at 72% hydration.  Hamelman pointed out in his recipe potato will retain moisture and therefore release it later.  If you increase the wholemeal flour again it will drink more water

  • 800g white bread flour
  • 100g wholemeal bread flour
  • 480g water
  • 330g levain (fed equal water/flour 8-12hrs before baking)
  •   10g fine sea salt
  • 225g cooked potato (baked as above)
  •     8g finely chopped fresh rosemary
Add everything except the potato and rosemary.  I leave it to rest for 30mins-1hr then add potato and rosemary on my first fold.  I have also done autolyse  then continued as per normal…didn’t find any difference in finished results.  For my folding method and baking see the Walnut & Raisin post here.