Sourdough bread

Brother Green's sourdough starts with starter. But how is the starter started?

The yeast is already on the flour. Starting the starter is the same as feeding the starter, equal amount of water and flour by weight. That's twice as much measured flour as measured water. Say, one cup water, and probably 1 + 1/2 cup flour and just let it sit there unattended for three days. Boom. There's your sourdough starter.

Then it needs to be cultivated. That's fed twice a day at the same time each day. Like a pet. To keep it active. If you stop and put it in the refrigerator then it must be brought back to life again, back to full activity by regular feeding.

You can manipulate this with warmth. The warmth of your personality and an incandescent lamp, but mostly a lamp. 

And you can manipulate this with chill. He ferments in the refrigerator overnight. To slow the activity. The next day it's allowed to warm up. You'll notice a great difference in flavor when you ferment your loaf for three days.

Or ferment the dough chilled for three days and form the loaf before baking. 

Autolyse is the process of enzymes in wheat breaking down wheat molecules once the flour comes in contact with water. The flour has begun destroying itself.