Disclosed is a method for adjusting the thread-tensioning conditions at least during the starting phase of an electronically controlled gripper shuttle loom or rapier loom (L) by inputting into the control unit a characteristic which is associated at least with the thread quality that is to be processed and using said characteristic for controlling the brake. According to the inventive method, several expert results (K1 to K5) of at least brake actuation characteristics (A1 to A5), which provide optimal thread-tensioning conditions at least during preliminary tests with different thread qualities, are determined during said preliminary tests and are encoded differently for the different thread qualities. An expert result which matches the thread quality that is to be processed is selectedfor at least one brake actuation characteristic (A1 to A5) and is input into a programmed electronic expert system (E) of the loom (L), and said brake actuation characteristic is adjusted and used atleast during the starting phase for controlling the brake.