I've been reading and thinking about sourdough growth. Most instructions refer either to time or to the activity of the start. It is asserted in at least a few places that different starts may be "faster" than others though I have a hard time believing tha if one is to believe that the dominant species in those starts are L. sf and C. milleri.

It seems to be a common belief that when the start or dough has risen as high as it goes and stops rising, that the start activity has peaked. In other words, that it enters the transition to the static phase. But I wonder if this isn't an erroneous assumption. Dough, and especially the more fluid starts, are hardly airtight. I think the only thing that can be said is that an equilibrium has been reached where gas production is at least high enough to counter gravity to the extent that the gluten structure will allow it to rise.

It seems like this may even be true even early or midway through the exponential phase, or well into the death phase. Or maybe not—I'm not sure and this is my question. Does anyone know of a good way (without scientific instruments) to estimate the growth phase of sourdough? Particularly, the transition to static phase, but any indication that it's in static phase would be useful.

Hi everyone!!

Boy am I happy that I found this site!!  I am having trouble (of course) with what I thought was my first attempt at sourdough starter..

I am using BBA method for Seed Culture, hoping to get to the Barm stage at some point.  I have two questions.  #1) I see here that many say that this method (BBA) is a method for Wide Yeast NOT Sourdough starter.  Can someone clear up the difference for me?  And how does one start a Sourdough Starter?

More Importantly... #2)  Having trouble getting my seed culture to develop according to what BBA says should be happening...  This has been my method and results...

 DAY 1:  4.25oz coarse rye flour & 6oz room temp water (NYC water run through my Brita filter).  Put in plastic beaker, marked height.

DAY 2:  Saw small rise (I think maybe 50% or less-can't quite remember).  Mixed in 4.5oz bread flour & 4oz water.

DAY 3:  I think this is the day that I had a pretty big rise - maybe double, maybe a bit more.  Discarded 1/2 the starter.  Added 4.5 oz bread flour & 4oz water.

 DAY 4:   maybe 50% rise.  BBA said that I should have had at least a double this day, or to allow it to sit out another 12-24 hours - so I left it alone until...

DAY 5:  Still no double, maybe 50% rise - decided to  discard 1/2 and feed again.

DAY 6:  Same - no double, but fed it again.. 

Day 7 - TODAY.  Looks like I had 75% rise, but then it fell back again to 50%.  The past couple of days (I'm getting confused, should have kept a journal) it seems to rise best between when I feed it and maybe 6-8 hours later, then it seems to stall and then falls back by the time it gets around to 24 hours.. 

 AM I STARVING IT?  I've read that many methods discard and feed every 12 hours.  Should I try this?  I'm still waiting for the double rise without falling - then BBA tells me to use 7 oz of this "seed culture" with 3 1/2 cups (16oz) flour and 16oz water to make the barm.

 This that I've made smells a bit sour and a bit bready - not bad, I think that day 3 was the worst smell (and the best rise-was this just bacteria.?

 Sorry for the long post, I appreciate any help that you can give me.  I just fed it for today, may try to feed again in 12 hours.

Thanks.