Baker Filippo Caiole’s doses are for every 10 kilograms (22 lbs.) of flour use 3 kilograms (6.6 lbs.) of starter and 5-6 liters (1.3 - 1.5 gallons) of water.
Making a Starter
Dissolve the yeast in the warm water, mix in the flour and stir well and at length, encouraging the gluten strands to develop, until the mixture is tacky and elastic. Cover with plastic wrap (I like to leave an air hole in case some natural yeasts from the environment care to participate) and let it stand overnight. (As a disclaimer and for purity’s sake, I admit to not having tried this in the United States with U.S. ingredients.)
Making the Bread
Mix 300 grams (10.5 oz.) of starter, 500 ml (2 cups) of water, and a few cups of flour, adding flour as you go along. Start with 1 kg of flour (2.2 lbs) and keep adding flour until it looks right, not necessarily using all of the flour. (Most bakers do it like this, most cookbooks tell you to add a little bit more yeast to the starter and water, which makes me wonder why you bother with the starter at all…)
Make a smooth mixture and then knead it for about 10 minutes, adding some flour along the way but not too much as the dough is meant to be very light and sort of sticky.
When the dough feels right (is elastic, smooth and pretty, makes a nice ball, bounces back when I poke at it), I put it into an overly large oiled bowl. I use my hands to spread a thin layer of olive oil all over the inside of the bowl, turn the dough over once so there’s an oily side up, cover it with a kitchen towel and place it in a warm spot until it doubles in size (I check it after an hour).
By now the dough is very light, fluffy and sticky enough that you may think you’ve erred. Bear with it though, flour your hands and all surfaces of contact, and gently divide it into 2 parts, shaping them as you like. Round is an option, oblong would be the most Tuscan. Either shape them on the baking pan on which they will be cooked or if you’re using a baking stone shape them on floured, overturned baking pans that you can use as a peel in order to slide them off onto the hot stone.
Let the forms rest a second time, covered with a cloth, until they double in size (checking them after 45 minutes).
Slide the loaves onto the stone floor of a hot oven (in a regular kitchen oven, use a stone if you have one and preheat well ahead of time to 450 F) and bake them for 35 – 45 minutes. I test them for doneness by tapping on them, they sound hollow when they’re baked through. I tap on the top, I use a kitchen towel to turn the loaves over and I tap on the bottom. They should sound relatively hollow, they should have picked up some nice color, and they should not be stuck to the cooking surface. When they’re cooked to satisfaction, take them from the oven and let them cool on a rack.
My mother would cut a slice while it’s still warm and slather it with butter. A Tuscan would wait, rigorously, until it’s cooled, and drench it in olive oil. I’d slice it, toast it over some coals and then dress it with interesting salt, dried oregano and a spicy green olive oil.