I've got to give you credit for some of the most amazing crumb shots I've seen.
I decided to copy your formula to see if it worked in Tampa. I was told my another forum member (Bob, you know who you are), and my wife (refuses to hang out here) that 70% hydration is crazy - hard to handle, slack dough, just a mess. Still, I was persisted because I've seen your pictures. The result was ... a really great crumb structure, even here in Tampa, even with a pinch of molassas added.
I did have to use more bench flour than usual when balling the dough to keep it from sticking to my hands, and flour again when stretching and placing on the peel.
So it was all good except that I didn't like the white underside of the crust as I pulled it from the oven. Do you have any tricks to minimize that? I use a combination of flour on the skin to minimize stickyness and corn meal sprinkled over the peel. Any suggestions?
Dave thank you so much for the feedback. It pleases me greatly to hear that I was able to help in someway. I'm extremely please that you have been persistant and able to see the benefits of a higher hydration dough on your crumb. I can tell you now that you are very close to achieving a great crust. Hopefully I can help you dial it in further.
First, I want to make a few comments about high hydration doughs. They have only one purpose for me and that is to create a bigger oven spring provided that you are baking with high enough heat. The 2 drawbacks to a higher hydrated dough is that it's tricky (at first) to work with them until you get use to it and that you MUST bake them longer. They don't work with a short bake b/c it leaves too much residual moisture causing the crust to go soft after resting a bit. For my taste (and most members I've talk to) the ideal crust and crumb is slightly crispy on the outside while the crumb is airy, light, and moist. These 2 ideals of crust and crumb are a bit of a contradiction in character if you think about it. Too high a hydration rate relative to the flour used and too short of a bake time and the moisture is not bake off leaving a soft crust and sometimes unbaked crumb that becomes chewier as it sits. So an ideal bake time for a higly hydrated dough should be in the 3-4min realm. Adjust your baking temps to achieve this time. So with some tinkering we can actually find a happy medium or balance to these 2 ideals.
So high hydration doughs definitely has it's limitations. The goal here is NOT to see who can make the highest hydration dough possible. My use of hydration is dependant on 1) my dry and hot climate that I live in and 2) by the strength of flour or blend of flours that I am using that day.
When using Caputo 00 flour I tend to go about 65-66%, AP = ~68%, BF ~69-70%, and HG 70-73%. If I was living in a humid environment such as yourself where my flour isn't as dry as it is now, I would likely decrease each of these by 2%. This is purely a guestimate as I have not made dough in a humid climate.
So for anyone wanting to do what I do, adjust your HR accordingly to your local climate and the type of flour you are using.
The reason I list a range of HRs for a particular type of flour is that there is NO magic # here. It's done by feel. I always try to get the same consistent feel in the dough regardless of the type of flour or blend of flours used. This way I get consistent results each time whether using caputo 00 or HG flour.
Dave, I'm going to answer your question in a minute but thought I would explain in detail so that you can have a better understanding of how and why I do things a certain way.
I usually bulk ferment to double, then divide and ball and proof to almost double again. After the bulk ferment is a really important time for me. When I pull the dough out of the container, this is where I will do several folds depending on how the dough feels. At this point after the bulk rise, the dough should easily windowpane, signifying that it has good strength. If it feels wet and sticky, I'll do more folds (without adding more flour) to build strength into the dough and this makes it less sticky. This is where if I ball up the dough, the dough should have enough strength to hold it's shape. This is where I look for a satiny and smooth finish.
The majority of the gluten should have been already developed during the kneading of the dough. I also add folds after the kneading if the dough needs it. This is usually what is meant when a member says I finish the dough by hand after kneading with a mixer. Basically I am looking for the dough to hold it's shape well. Look in your Tartine book on the bottom of page 59. Something like that. I am NOT looking for the dough to window pane at this point. Even if the dough is a bit rough looking and not smooth like Chads, I'm not worried about that.
Why? B/c I'll build more strength into the dough later AFTER the bulk rise and during balling if it needs it.
After the bulk to double, I do additional folds if the dough needs it, and then it's time to divide and ball. Even during the balling stage, I will add in more folds if the dough needs it. Basically enough so that the dough will hold it's ball shape, have a smooth finish, is tacky BUT NOT too sticky. During this phase, you can add a bit of bench flour to the doughballs but it should take very little and not be sticky. If it's sticky, then continue doing folds to the dough until it is not. If you feel like it, then let the dough rest 5-10m and then repeat with a few folds. You should note an immediate improvement in the strength of the dough and a decrease in the stickiness. But I rarely need to do any additional rest periods at this point b/c I will have already built enough strength into the dough during the kneading, folds after kneading, bulk rise, and folds after dividing and balling.
Sorry if this sounds confusing, but this should help further explain. So really how much folding am I doing anyway? Well enough so that when the balls proof up, they should flatten out a bit but not too much. Look on page 60 at the first picture. That dough has rested about 20 min and flatten out. Well my proof dough will flatten out a little less than that if proofing on a flat surface. I usually proof in bowls or plastic containers so I can't really see them flattening out but I did proof dough on plates and in pyrex dishes for awhile to observe the effect.
This is really important how much they flatten out during proofing. Why you ask? Because this tells me how much strength is in the dough. If a dough doesn't flatten out at all then obviously there is too much gluten built into the dough. If it flattens out too much then there is not enought gluten built into the dough.
The FOCUS is not how high a hydration you are using and how difficult it is to work with. The focus should be how much gluten have you developed into the dough regardless of the hydration. When there is sufficient gluten built into the dough, even highly hydrated doughs aren't real sticky and are not that difficult to work with. If the dough is sticky, then it will also be too slack, and as Bob puts it "crazy -slack dough, hard to handle, and just a mess."
If your dough is such and requires a lot of bench flour during the balling stage, then you haven't built enough strength into the dough. When I work with my dough during the balling stage, I will use a very minimal amount of bench flour and sometimes none at all here. The dough should be tacky but not too sticky. A little sticky is okay. A little bench flour here is okay too.
After they proof up and before I stretch the dough, YES I will use a normal amount of bench flour but no more than anyone else. The amount of bench flour I use here is not really dependant on my hydration ratio whatsoever b/c I have enough gluten built into the dough.
So when the balls proof up they should flatten a bit (if free standing) but not too much. If they flatten out too much and are too slack and too hard to handle, then you need to up your kneading times or add in more folds before the bulk and or after the bulk and or during balling. You typically don't want to reball after a dough has proofed. If you have to then you have to wait 40m or so until the dough has relaxed again and this might put you into overfermentation. It's better to adjust your gluten development on the next batch, so keep good notes.
When I open a dough I usually liberally coat the dough in bench flour and shake off the excess. This is the only bench flour that is require to open up a highly hydrated dough. Nothing more than what is seen in the multitude of youtube videos showing professionals opening up dough. This highly hydrated dough should open easily and have a little retraction on the peel. If the dough retracts too much on the peel, then this is a sign of overgluten developement. If there is NO retraction, then this is either undergluten developement or the dough is overblown (overfermented). I use only a small amount of AP flour to flour my wooden peel. The skin goes on, sauce, cheese, a quick picture and into the oven. I don't have the skin sitting on the peel for a long time. Less than a minute for sure, maybe 30-45s. I don't have any issues with the dough sticking either. Very very rarely.
Okay to finally answer your question.....the white underside is likely due to excess bench flour 2nd to not enough gluten developed into the dough. Keep practicing you are almost there buddy.