I have tried to make perfect croissant for a several months using my raisin yeast water. I will write how to make raisin yeast water that I have kept for a couple of years. The center’s crumb looks little tight.. I am trying to get more open crumb in the center. I always fold the dough 3x a letter fold.
The crust stays crunchy for a couple of days, and very tasty, of course. I still study this formula to complete.
I put the roll-in-butter in the dough like the way ( The picture below):