Still working on making a seed culture, using dark rye flour, so I can create my first barm, so I can make my first sourdough loaf. To make a long story short, conflicting information I had read caused two misfires with my first two starters. Both misfires hinged on the problem of knowing for certain when a seed culture has been successfully created. In one source, it said wait for bubbling and doubling. In another source, it said wait for yeasty smell AND doubling. In another source, it said if there is a yeasty smell, it means the yeast are dead! OK, so I plunged ahead. Well, on my first starter, I got the doubling and proceeded to next stage, i.e., mixing up a sponge. Nothing whatsoever happened, not even bubbling, for 5 days (not the 4-6 hours I was hoping for!!). On next attempt, I got bubbling and doubling, but understood that was just bacteria action. For 6 days now, nothing further has happened, despite my following instructions faithfully.
Then I whipped up another batch as per BBA seed culture instructions, but ordered in some food pH test strips. Day 3, which is today, I got doubling, and followed Reinhard's instruction to toss 1/2 and feed again, nevertheless. But where, really, really, is this concoction at, anyway, I asked myself? Gas or yeast expansion? The smell is --- i don't know--- definitely not yeasty, but it is not unpleasant. My nose hasn't told me anything, really. So I dipped in my handy-dandy pH strip and discovered the culture is at 5. And a couple of bubbles are just starting to make their appearance.
Now I KNOW where my culture is at. (Thank you, Debra Wink.) I look forward to tomorrow, when I probably will be ready to make my barm, and definitely will not be tempted to think that maybe any future doubling is bacteria-caused. And yes, I will take another pH reading just to make sure.
I don't know if anyne has used pH strips in their baking, but as for me, I believe they are a great and really cheap tool which I intend to use from now on.