Sourdough Boule Height

Toast

using Vermont SD recipe. Getting good rise in final proof and good oven spring. But dough spreads during transfer from baneton to DO and don't get height I want. Have tried to up my shaping game but still not happy.

Tighter shaping could be the reason, or a too weak gluten network. Try mixing it a little longer next time in the beginning, it should make a difference.

Other than that, it's normal that the loaf spreads a little after transfer, especially after scoring.