Surface tension is very important.   I should always keep in mind when I shape the bread. I decided to explore this one more time and observe the benefits of creating strong surface tensions in order to improve how the loaf of bread rises during proofing and to improve how the bread opens up while baking. I made a big 3kg loaf of sourdough bread, with homegrown yeast. I chose the simplest shape, the boule, and pay extra attention to create a great surface tension. Great result! The bread was growing a lot during the proofing, rising up in all the directions, on the side but also upward. After proofing, the bread is signed and baked in the oven. The bread took a nice deep inhalation, breathing through its signature.

For the starter (900g):

• 300g barm (50%-50% flour-water)
• 390g of whole-wheat flour
• 210g of water

Notice this starter is made of (2/3 flour, 1/3 water), the same ratio as for many bread recipes

For the bread dough(~3kg):

• 900g starter
• 1200g flour
• 800g water
• 36g of salt

Knead for 5-10 minutes. Let rise until double (may block the dough in the fridge overnight for flavors). Shape with great surface tension. Proof for 1-3 hrs or until it almost doubles. Preheat oven at 500F with baking sheet on the bottom rack for steam. Prepare boiling water on stove. Sign the broad and put in the oven. Throw boiling water on baking sheet, and close oven immediately to keep the steam in the oven. After 10 minutes, rotate bread, let the steam out and cook at lower temperature (420F)  for another 30 to 40minutes, depending on taste and you like the crust.