French rustical sourdogh bread

It is not the first sourdough loaf that I made but it's the first that I'm really proud of. Recipe is taken from polish bread site ("Chleb-moja domowa piekarnia" - "Bread-my home bakery"). I finally realized time is the most important ingredient... It'll be my first attempt to post recipe to Yeastspotting.

Ingredients:

Levain - 270 g

• 30 g rye surdough starter -  starter should be rather mature
• 140 g wheat flour (850 type)
• 10 g rye wheat (720 type)
• 90 g water

Dough - ca. 1,6 kg

• 270 g levain as above
• 800 g wheat flour (850 type)
• 50 g rye flour (720 type)
• 450 g wody
• 18 g salt

Yield:

One, quite big loaf about 1,4 kg

Method:

1. First prepare the levain - mix all the ingredients, you'll have thick dough, leave covered in room temperature for about 12 - 14 h
2. Next day mix flours and water only to combine ingredients, leave covered for 1h
3. Add salt and levain and mix about 20 minutes, dough should be medium compact
4. Transfer dough to lightly oiled container, cover and leave for first fermentation for 2,5 h
5. Fold it after 50 minute and 100 minute of first fermentation to reach smooth surface
6. Form one big or to smaller loafs and transfer to banneton for second fermentation - in room temerature it'll be about 2-3 hours, at 10 C about 8 hours, at 6 C about 18 hours.
7. Preheat oven to 240 C, cut the loaf, and place in the oven
8. First 6 minutes bake with steam
9. Total baking time is about 35-45 minutes
10. Cool on wire rack, and wait until it is not to hot...