Young vs Mature Starter: Misc Questions
I am struggling with the difference between young and mature starter.
A young starter is when it is still growing, but to the point when it is usable for making bread.
A mature starter is when reached or just past its peak, just starting recede, the acid is increasing, but is still usable for making bread.
(The two other stages, in which the starter can't be used for making bread, are: prior to Young when it doesn't have enough yeast or bacteria etc, and too old a starter where acidity has increased to the point it's killed too many of the yeasts.)
Some miscellaneous questions:
1) What is the best way to tell in terms of appearance/odor/taste/float test/doming/doubling etc (for both liquid and stiff) when a starter has reached the viable young stage? What is the best way to tell when that young stage has crossed into (for both a liquid and stiff) the mature stage?
2) Hamelman calls for "mature" starter for the seed/chef that builds the levain. Since it's just the seed, why does it need to be "mature" given it will be elaborated into the levain a tout? Wouldn't young starter work just as well. Isn't it the final levain itself that matters more?
3) For a typical pain au levain or country style loaf or miche, should the final levain be young or mature?
4) How do any of the answers to the above change for rye or for other whole grain flours?
5) Does any of this change by nationality? For instance do Italian lievito vs German Vollsauer vs French traditions favor a Young or Mature final levain (in the definitions at the top)?