Croissant experimenting

I have always been curious during class as to know how some bake shops like Thomas Haas and the few I visited in Paris are able to create croissants with massive volume and visible flaky layers.

I have been doing a little research and decided to experiment with how many and which turns to give the dough. Also I think the thickness of both the dough and butter as well as the final rolling to make up the product as well as the baking temp will affect the way the product looks.

So in the end I decided on having the dough as thick as 8mm and the butter at 6mm. I enclosed the butter without a single-fold and proceeded with a book-fold and then a single fold.

I shaped two different batches from the same dough but changed a few variables. The second batch was proofed at a cooler temperature for 4 hours instead of a little warmer for 3. I also hit them with a preheated oven of 246C and immediately dropped the heat to 218C. I believe this will give them more height by allowing the moisture in the butter to quickly evaporate.

I also rolled them out a bit thicker than the first by at least a mm or more but I think this created more crunchy rather than crispy layers.

The problem I had with both however was butter leaking during baking. This can be either bad enclosure of butter (not an even layer of fat and dough), weak flour (when oven spring happens, layers tear apart and butter seeps out), low temperature (butter melts before dough can rise), too much butter or under-proofed.
I can say judging from the photo, my layers of butter and dough are pretty nicely made, the temperature I baked both was high enough and my butter to dough ratio was industry standard (25% butter weight to dough).
Where I think the problem might be is I didn't have enough strong flour available(AP, bread) so I mixed what I had with pastry flour, this also affected the proofing because I can physically see the layers being split apart on the surface.

My next attempt will be to use European style butter which is "dryer" than the other stuff, use the right flour and try three single folds.
In the end they still turned out well and the family devoured them.

first batch

layers of dough and butter

cutting

shaping

visible layers during proofing

not the honeycomb center I am looking for

double egg yolk glaze

you can see where the layers have teared

second batch with much thicker layers from a thicker final roll-out