Chocolate bursting out of pains au chocolat
Okay, I've been tweaking a croissant recipe for several months at the restaurant where I work. Initially, my problem was that the butter was leaking out pretty badly. I've troubleshot that issue and seem to have it pretty much under control. But now a new problem has cropped up, and I'm not sure why this is happening. As the pains au chocolat bake, the chocolate pistoles that I use (Valrhona blond chocolate) burst out of the center of the pastry--not the edges, but right in the middle where the pastry meets the parchment. The layers of the pains au chocolat look great--they have the characteristic honeycomb crumb that you want from a croissant, but the chocolate literally explodes out of the dough, leaving very little chocolate still inside the pastry.
My process is as follows: on day 1, I make the preferment, make the dough, and fold in the butter (3 turns). I freeze the laminated dough for a few hours and take it out of the freezer before I go home at night. On day 2, I roll out the dough and shape the pains au chocolat. I then freeze them overnight. On day 3, I take the pains au chocolat out of the freezer, proof them, double egg wash them, and bake.
Other things that might be a factor: the baker's percentage of butter is 55%. I use a slightly better butter than your run of the mill restaurant butter, but I don't know exactly how high the quality is or what the exact fat content is. The ovens where I work are pretty awful. At home, I set my oven to 425, then immediately lower to 400 when I put the croissants in. The croissants bake in about 15 minutes and are beautiful and flaky. At work, I make the croissants smaller, but even so I can only set the oven to 325 max (no fan--tried that and it was a disaster), and the croissants take at least 30 minutes to bake. I rotate the sheet pans in the oven every 10 minutes to try to get them all to bake evenly. There's not much I can do about the oven problem. They are what they are.
But I have no idea what would cause the chocolate to burst out of the dough. I tried using chocolate batons, and the same thing happened. Could it be the freeze-thaw process? Any insight would be helpful.