High ph in mother starter
Hi there--I am new to this site, but already I am grateful all the advice this site's members provide. This is my first posting, and I was hoping someone could help me with something I am seeing in my mother starter.
I've been using Reinhart's starter method from Artisan Breads Every Day, where a mother culture is built from a seed culture. Each sourdough bread uses the mother culture to create a wild yeast starter for the bread.
I understand that ph should be in the 3.5-4 range. However, my ph is at 4.5. Given this, my mother starter still seems to rise well after refreshment. In fact, it doubles in volume in about 4 hours. However, when I create a wild yeast starter for a bread from this mother starter, the wild yeast starter takes very long to double in volume -- typically more than 24 hours! For this wild yeast starter, the ratio is 25% mother starter to added flour. I suspect that the reason for this long rise time is the high ph.
Am I correct in my suspicion? Does anyone have any thoughts on what I should do about this?
Thank you very much in advance for your help!