I've never baked this much bread before, so I worked out a timeline—and good thing too, since I needed to begin Friday to have the breads ready on Sunday. I started by feeding 50 grams (about a quarter-cup) of sourdough starter Friday morning, building it to 150 grams. On Friday night, I fed it again to take it up to 450 grams. Saturday morning, I refreshed it a third time. By Saturday evening, when I needed the ripe starter to make my doughs, I had over 1500 grams (3.3 pounds) of the stuff. With that steady feeding every eight to 12 hours, the starter was bubbling, itching to impregnate the dough. It's pictured at left, and below, in the big bin on the right.

Photo by Samuel Fromartz
I measured out the flours and began mixing the dough. I don't really knead or use a mixer. Rather, I combine the ingredients by hand until they come together. I let the shaggy mass rest so the flour slowly soaks up the water, then fold it over every hour or so to develop the gluten. By the end of the process, the dough glistens with moisture. If you pull away a small piece and stretch it, you should be almost able to see through it—the so-called windowpane test that shows when a dough is done. This folding technique is a cousin to the no-knead method, since you just fold over the dough and let time do its work. It works beautifully, especially since my home mixer couldn't handle the volume of dough I made.
Now the magic began—the first rise, the source of all flavor—and luckily it was a chilly night. Why was that important? Because I let my sourdoughs rise in an unheated basement storage room that is about 55 F. That's the perfect temperature for a languid fermentation, when the sugars in the bread develop. Bakers buy proofing cabinets that cost thousands of dollars to get this temperature with refrigeration. My solution was less precise, but it worked fine. The Genzano and baguette doughs rose in the refrigerator, since they contained instant yeast as well as sourdough and I wanted a slower fermentation.
At seven the next morning, I took the pain au levain dough out and let it warm up for about an hour. I then shaped three boules, letting them rise for two and a half hours. In the meantime, I heated up the baking stones in my double oven. Then I repeated this with the Genzano loaf, about an hour later, and then the baguette.
The rise went well, full of oven spring. I attribute that to the levain, which you'll recall had built over a 52-hour period with successive refreshments, including the last one in the dough.
I finished baking at about 2 p.m. and let the breads cool, then delivered the loaves for the dinner. Jean-Pierre Moullé, the chef at Chez Panisse, was there to greet me. We talked briefly about the breads and I mentioned I was a home baker, not a professional.
"I know, but you did not bake these at home," he said.