Time: 1.5 days
Yield: 1 300g loaf
Bread flour: 240g
Whole wheat flour: 60g
Ripe starter: 60g
Temperature is super important! Check your dough temperature at every stage of bulk fermentation (Autolyse - Rest). I keep my dough temp between 74-76F.
Keep a "sidecar" (a chunk of dough after you add the salt, see picture below). I learned of this technique from @rosehillsourdough. A sidecar will help you keep track of approximately how much the dough has risen during bulk fermentation. You're aiming for 1.6-1.8X in the sidecar, though this is highly dependent on your starter strength, dough, and fermentation temperature. For me, this means bulk fermenting for ~5-6.5 hrs at 75F.
Start with lower hydration (73-75%). If you are a beginner, it's important to master the basic technique before increasing hydration. High hydration dough is very hard to work with and I guarantee it will not lead to a more open crumb (that's nearly all dependent on your starter).
Pop air bubbles during bulk fermentation. These air bubbles are a sign that your starter is working (yeast is active, eating sugars and producing CO2), BUT if you keep them in your dough, you will end up with a funky crumb. Pop 'em until your dough is in the banneton!
@fullproofbaking has an AWESOME tutorial; check it out!
I highly recommend you look at her video! I use her method, which you can see in my schedule at the bottom:
Autolyse flour and water for 1-2 hours at room temperature
When your starter (aka levain) has peaked, add levain to dough. Rest ~40 min.
Add salt. Rest ~35 min.
Stretch and fold, rest ~30 min.
Laminate, rest ~30 min.
Coil fold 4x, ~30-min apart.
Rest for 1-1.5 hours, until sidecar has reached 1.6-1.8X and your dough is noticeably puffy.
Shape, put in banneton, rest for 10 min, transfer to fridge overnight.
Next morning: preheat oven at 490F with double dutch oven for 45 min.
Score, transfer to shallow end of dutch oven, put lid on, transfer to oven.
Bake at 490F for 20 min with lid on, reduce temp to 450F and remove lid, bake for 20 min with lid off. Top with aluminum foil in last 10 min to prevent over-browning.