Traditional mozzarella problem with PH

[arie_pk]

Hi
I started making acidified Mozzarella. and reached very consistent success. In my place there is only one brand of milk, which is  homogenized and low pasterized that can be used. So i am adding a bit of calcium Chloride, and measuring the acidity of milk prior to adding Citric Acid, and adding it according to the start up acidity. Once i reached around 5.25 PH after the Citric Acid, the rest is a breeze.
The problem starts when I try to use the traditional method. I tried it with a thermophilic culture, and also with a local bio yogurt, with the same result. The curd will break apart during streching at 5.2 Ph and bellow. It does start to stretch at around 4.5 Ph!!!
Does anyone have any idea of the reason!!!.
I am using a PH meter as well as Litmus paper, so my PH readings are correct.

[gadjahberlari]

i had the same problem, using thermophilic culture then rennet. Drying the curd till gets ph 5.4-5.2, then starts stretching.

curds are pulled apart and starts to break down at approximately 30 cm in length.

we started to use salted water (75 g for 5 liter) to stretch, and with higher temperature (75 degree, now i used 85-90°C). Using double tempering method

It does its magic and started to stretch easily