It's a bread with medium hydration, 73% and 25% wholemeal flour. A strong flour (high protein content) will help. If you don't have strong flour you can lower the hydration.
It perfectly combines the special taste of long leavening at room temperature, the crust specific to low-hydration loaves and the lacy crumb texture of the high-hydration breads.
80g whole wheat
245g white bread flour
65g sourdoug starter (100% hydration)
19:00 mix flours & water then rest (autolyse)
20:00 knead with starter for 4-6 mins. then rest
20:30 knead with salt for 4-6 mins. then rest
21:00 strong fold on table then rest
21:30 coil fold then rest
22:30 coil fold then rest on room temperature ~ 22 degrees Celsius
7:00 AM moved into the fridge to cool down
7:30 AM shape like ciabatta then rest
9:30 AM bake 10 mins. at 250 degrees Celsius on baking steel with steam and 25 mins. at 220 degrees Celsius without steam