Over or under proofed?

Your final product looks great.  I am thinking that the hydration is a little high and the loaf is on the verge of being over proofed.

Try the two finger indentation test for proofing.  Lightly push in the dough with two fingers (slightly spread apart).  If the indentation immediately springs back the loaf is under proofed, if it slowly comes back it is ready, it it does not spring back then it is over proofed.

I also suggest adding a little less water to the dough,

Ford

If 70% is your final hydration then your slightly high than my usual hydration of 67%. I agree with Ford on the over proofing. I would cut back 30 min on the final proof and see what that does for you. Also consider if you are putting enough surface tension on the loaf during forming.

I think it looks good, too. 

Two thoughts: I agree that if you're using all white flour (except a little rye in the poolish), 70% percent may be a little high. 

Also, I've become more of a fan of doing a retarded final proof. I used to have trouble with spreading, but chilled doughs don't do that as much. I don't know how that would fit into your production schedule; you'd probably need to adjust a bunch of things to accommodate that change, but it might be a worthwhile experiment. Maybe you could do a small test batch to try out the timing and see if you like the results. 

I wouldn't change the hydration unless you are really set on a round loaf profile (but with a less open crumb).

That crumb certainly doesn't look underproofed to me, so do work on your proof poking.

I'd first try some additional folds, along with a bit less proofing.  The folds with help build a bit more strength, and help even out the distribution of gases (i.e. the BIG bubbles).  That along with a bit less proofing should help with the loaf profile.

Nice work!

at 100% hydration and 70% of the dough at 70% that would give you about 79% hydration overall which is a little high for this kind of white bread. I like to be around 72% to 75% or so.  It looks like the dough is proofed fine with the great spring and crumb that you got.   Another thing you could do is to refrigerate the dough for 30 -45 minutes before you tip it out for scoring .  That might not mess up your schedule too much.  I would add another S & F too and do themon 30 minute intervals so you arenlt adding any time to that process

Happy experimenting

Hi Matt,

I think your fermentation process is too long, hence why you are struggling to manage when you load to the oven.   I am a little confused by your terminology.   A poolish and a sponge generally use bakers' yeast.   True sourdough breads are raised only with natural levain culture; bakers yeast is forbidden.   Can you clarify this please?

If it helps, I use levain @ 60% hydration and 25% pre-fermented flour in the final dough.   My leaven has a minimum of 2 feeds, and is ready to use in just 3 hours after the final feed.   Do you want to make your bread sour?   I seek to make the product only with natural levain, but I don't want a sour taste in the finished bread.

So, you've moved on; hearty congratulations!

Best wishes

Andy