Neil, let me help u to make good mozzarella
add a very little culture (powder) don’t use ur way of preparing it in day before… temp 32c wait 15 minute , add rennet
then cut and stir, cook @ 39 in 30 mins
then drain, and let it set and mate, then cut slices and leave the pot in 39C water bath, turn them every 15 min to make them all same temp, drain whey every turn
then u will see in hour to three hour that the cheese slices start to become flat, but the right way to test is by pH meter 5.1 or by taking a small piece every 15 mins and put it in 75C hot water, and try to stretch,
in first stage the cheese will not stretch and break pH over 5.4 then it will start to stretch a little bit pH5.3 and 5.2 then it will stretch very beautifully for long string when pH5.1 then it will break again when the pH bellow 5.0
bring a gallon and try it, and do not rush, and avoid your historical acid problem, and u will thanking me, when u end up with very shiny smooth mozz balls