This is what I had after 48 hours...
Here's the thing. When I broke the dough "seal" that had bubbled through the nailhead opening at the top of the jar, it had the right smell. A pleasant sour or beery smell. Plus it looked right:
I decided to take a chance, feed the starter again, and see what happened that evening.
Same thing. Same crusty top. Same delicious bread-y smell. Same great bubbly look.
Re-read S. John Ross.