Sourdough pizza

Before you start

You'll need

• Kitchen scale
• Large bowl
• Clear straight-sided container, about 3 liters, with a lid
• Instant-read probe thermometer
• Bowl scraper and bench scraper
• Four lidded containers, or a covered tray, for the dough balls
• Pizza stone or steel, or an upside-down baking sheet
• Pizza peel, or a flat board
• Parchment paper

Step by step

1. 1

   The night before, make the levain

   In the evening, mix 10 g of your active starter with 100 g of bread flour and 100 g of water in a jar. Cover it loosely and leave it at room temperature. With that much flour and water it takes longer to rise, so it peaks in the morning: it will have doubled or tripled. You'll use 100 g for this recipe; the rest can go back into your starter jar.

   Tip: If you'd rather start in the morning, feed 60 g of starter with 60 g of flour and 60 g of water, and use it at its peak: when it has doubled, 4 to 6 hours later, before it falls.

2. 2

   Mix the flour, water and levain, then the salt

   In the bowl, mix 500 g of bread flour with 350 g of water, not hot, and 100 g of levain at its peak until no dry flour is left. Cover and let it rest for 30 to 40 minutes: this is the fermentolyse Illinois suggests for this dough. Add 10 g of non-iodized salt and pinch it into the dough with a wet hand until it's worked in.

   Tip: Bread flour is the white flour for bread, with plenty of protein: 11% to 13%. Besides flavor, salt helps build the gluten.

3. 3

   Do three or four sets of stretch and folds

   Wet your fingers so the dough doesn't stick. Take one side of the dough, stretch it up and fold it over onto itself; give the bowl a quarter turn and repeat until you've done four folds. Cover and let it rest for 20 to 30 minutes. Repeat the set 2 or 3 more times, with the same rest: the dough will get stronger each time.

4. 4

   Let it rise in bulk, watching the dough, not the clock

   Move the dough to the clear container and mark its level with a rubber band or a marker. Take the dough's temperature at the start and several times during the rise, and average it. Depending on that temperature, stop when it has risen:

   • at 80 °F, 30%;
   • at 75 °F, 50%;
   • at 70 °F, 75%;
   • at 65 °F, until doubled.

   It's done when the surface is slightly domed and pulling away from the edges, and sponge-like bubbles show on the sides. With the dough at 72–80 °F it usually takes 3 to 6 hours, but that's our house guide: the temperature and the rise are what count.

5. 5

   Divide the dough into four balls

   Turn the dough out onto a clean counter and cut it with the scraper into four pieces of about 240 g. For each one, fold one side into the center, then the opposite side, then the top and finally the bottom. Flip it over and, with the scraper underneath, turn it in circles to tighten it into a ball. Put each ball in a container greased with a few drops of oil, so it comes out easily later, and cover them.

6. 6

   Give them a night in the fridge

   Put the covered balls in the fridge for 8 to 16 hours, or a little longer. The longer they stay, the more sour the dough tastes, but don't go past three days. On baking day, take them out 1 to 2 hours before stretching so they warm up.

7. 7

   Stretch each ball by hand

   An hour before baking, turn the oven as high as it goes, at least 475 °F, with the stone or the upside-down sheet inside (our house rule).

   Flour the counter and turn out one ball without squashing it. Press with your fingertips from the center outward, leaving a ½- to ¾-inch rim untouched, and stretch it by hand to about 11 to 12 inches (our house rule). If it springs back, let it rest about 15 minutes and carry on. Move it onto the peel lined with a sheet of parchment paper.

   Tip: If you prefer, roll it out with a rolling pin, as the University of Alaska does. Flour is a powder and spreads easily: keep it away from food that's eaten uncooked, such as the basil.

8. 8

   Top it and bake it in the hottest oven

   Spread about 60 g of tomato on each pizza, leaving the rim bare, then about 60 g of mozzarella and a drizzle of oil. Slide the pizza on its paper onto the hot stone and bake it for 8 to 12 minutes (our house rule), until the rim is puffed and browned, the base is firm and charred underneath and the cheese bubbles. Add the basil when it comes out.

   Tip: The University of Alaska bakes its sourdough pizza at 425 °F on the bottom rack for 20 to 25 minutes. If your oven doesn't go higher, bake it that way: it will take longer than in a hotter oven.

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