Always Zero Ovenspring, pls help :)

Hi Charlie, 

the whys and hows of oven spring are the following

1) in unleavened dough, oven spring is due to gluten development, the dough is kneaded and then stretched and folded a lot, so that the layers are very thin and when baked they are translucent. This achieves phenomenal oven spring, for example, in puff pastry, that has no yeast, no sourdough, no soda, nothing, just water vapor that makes it spring so tall.

But its oven spring is legendary. It increases in volume in the oven about 10-12fold. Just because its gluten is so well developed, rolled out and folded, and the steam during baking lifts it up. 

2) in leavened dough, oven spring is due to gasses from leaveners and thanks to the extensible or soft consistency of the dough, such as in soda breads, cookies with baking powder, yeasted breads and sourdough yeast. It is stretchy enough to rise at least 4x during proof and then to double in the oven, to spring up under the gas pressure from those leaveners. 

 Image source.

In your case, both things haven't been working well enough.

Your leaven is not mature enough (doesn't have enough yeast in it, it is too young when you use it) and your bread dough is not kneaded enough nor stretched and folded, nor let rise sufficiently when fermenting (which stretched the gluten as well).

So you can see that there are very few pores in your bread slice with very thick walls, and your leaven never rose to the max and started falling, nor your bread dough rose tall, so in the end the tight mass was too stiff to stretch and rise and there was not enough gas produced by sourdough yeast because there were few yeast cells to begin with. 

My advice would be

1) Stir your leaven well when you mix it, really well, 300 turns minimum, then let your leaven/levain rise to the max volume (3x to 4x increase in volume), wait for its top to flatten out and start sagging a bit, then stir it and watch it rise again. If your mature leaven doubles under one hour after that, it is strong, with good gassing power, it will work very well in your dough. If not, let it rise to the max again and test its gassing power again: stir it and let it double, see how long it will take. 

2) do knead Your bread dough at least to the initial stage of gluten development and then do stretches and folds with wet hands on wet or slightly, only very slightly, greased table surface, to create good layers.

3) let your bread dough rise as it bulk ferments, just to make sure that it CAN rise big and voluminous. Normally, bread volume is 4-8 times bigger than initial dough volume. You can measure your dough rise in a measuring cup, to see how big it is able to rise. 

The rest of your recipe/process is ok, it should give you a good loaf of bread. 

• Knead more during mixing until you have more dough strength, then fold as you are doing during bulk fermentation
• You might try a lamination fold for one of the early folds and a coil fold for one of the later ones
• 60% volume increase for 90% bread flour might be a little low.  Look for some other signs of completed fermentation like jiggly dough, airy feel, bubbles on top, etc. 
• Make sure to build some more dough strength during shaping.  I find boules with tension pulls are easier than batards.  For batards, try to stretch the dough a little bit with every one of the folds and the rolling-up.  Do zipper type folds on the bottom before or after you put it into the banneton
• Proof in a bowl or banneton if you are not already
• Proof at room temp for an hour or so before you put it in the fridge; it should almost pass the poke test but not quite
• A closed dutch oven for the first 15-20 minutes of baking seems to provide better steam than any method with a pan under a baking stone.  

Good luck

Looks overproofed. 

Reduce hydration.  Reduce proofing time.  Reduce dough temperature.  Desired dough temperature is 23C-25C, my opinion is the lower range (23C) is better.  

I had similar trouble (still have if) when ramping the hydration past 65%.

Proofing can be as low as ⅓ before retarding and still the oven spring is ok. This is not a case of your starter being young or weak, it is you where the fault lies.

Play with the hydration first, then the proofing.

Amazing improvement. How many hours did it bulk ferment at room temperature? 

That’s interesting, thank you. My kitchen room temperature during th e day is about 21C. For BF I put the dough in the oven which I turn on briefly to get to 24-26C.  I go to 100% rise in about 8 hours .  My rise isn’t as good as yours though. I might try an overnight BF at room temperature and see how it goes .  

Everything about my baking improved when I started using the hint in the Tartine recipe for country bread.  The hint is:  wait until a bit of your starter floats before mixing the dough.  Since I started using that hint, my loafs are not gummy and they rise well.