Activation of Sourdough Starter

Different starters take different amouints of time to reach their peak.  You have to learn when your starter is ready to be used.  Also, it's not rocket science.  If you miss the oeak by an hour - or even 4 or 5 - the bread will still turn out fine.

When you feed a starter, it enters a lag phase where nothing seems to be happening.

After a bit, if the starter is thick enough (100% hydration or lower), it will start to rise.   This is the growth phase.

At some point, the starter's ability to generate gas and the starter's loss of gas through the surface will even out and the starter will have reached a peak.

After a bit, the starter's ability to produce gas will diminish and the starter will start to collapse.  In the early stages of this collapse you'll see fissures forming on the surface of the starter.

A bit later, the starter will shrink more until it is the same size as when you fed it.

The periods where I suggest you use it are from the peak rise to the point where it has little fissures on it.  When it begins to noticeably shrink, I suggest another feeding and catching it at the peak phase.

Mike

PS - if your starter is at more than 100% hydration and won't rise, I suggest that you cut your starter's hydration.  I find that very wet starters are more difficult to handle, especially for sourdough beginners.  Mike

I am not familiar with Mr Leonard's recipes but I have peppered another well qualified baker with questions about the refreshment of starters.

I will preface the advice given me by saying that the method to which this refers is to take a small amount of storage starter and create a "build" by using a cetain percentage of starter to quantities of flour and water.  The storage starter is not touched and is fed by other means.  When temperatures vary, it can take more or less time for the build to reach ripeness and I was experiencing problems with that.  This is the advice I got:

1. Get up earlier in the morning (to this day I'm not sure if this was meant as a joke or not.)
2. Use a smaller percentage of starter to flour and water.
3. Put a small amount of salt (taken from the salt you would use for the bread) into the build.  This will retard the build, but not kill the levain.  We must know that the organisms in levain will grow in the presence of salt - else our bread would not rise.
4. Control the temperature (if you want the build to grow more slowly - keep it somewhat cooler for the entire time)

Hope this helps - it did me.