First, let me say that I've done some searching and not found an answer to this specific question, so please read on before directing me to an existing thread. I know this topic has been discussed exhaustively.
Lots of natural levain methods described in the literature require the "discard" of a good portion (usually more than 50%) of your starter each time it's fed. For months now, I've adopted a system of managing my starter by reserving a very small amount (less than 50g) of the starter from what I developed for the day's baking for the two to four loaves I bake each day.
I keep revisiting Chad Roberston's "Tartine" and Ken Forhish's "Flour, Water, Salt, Yeast" and despite having given it a LOT of thought, I cannot for the life of me figure out why they have you make so much levain. For example, in Forkish's formula and method for his Overnight Country Blonde, he calls for the baker to make an entire KILOGRAM of levain, then use only 216g of the Kg for the final dough. In other words, if you save 100g for your next bake, you're left with almost 700g of levain that you have no use for. Forkish specifies that you can reduce the amount of levain you maintain (he suggests cutting it in half on p.136). Great. Now I'm only throwing away a little less than a pound of levain every day.
If, as Forkish claims, "you can pare down the amount of levain, fresh flour, and fresh water used with each feeding as long as you maintain the same ratios" (75% white and 25% whole wheat flour, 25% levain, 75% water...did i get that right? I'm extrapolating it from 100g levain, 100g whole wheat flour, 400g white flour, 400g water) why doesn't he recommend that bakers making the two loaves his formula provides for each day produce just enough levain for the bread they're baking and the levain to start the next bake? If you round down the levain that Forkish requires for the final dough in this loaf to 200g for convenience of discussion, that would require that you start with:
20g whole wheat flour
80g white flour
Actually, since you're going to need an extra 20g or so for tomorrow's bread, you'd want to go with a little more of everything in proportion, specifically:
22g whole wheat flour
88g white flour
You get the idea. That gives you the 200g levain for the final dough, and leaves 20g levain to do the same thing the next day.
I am actually doing this, and it works great. I have not tried the wasteful mountain of levain that the formula recommends. Should I? Why would the results be different? I can think of no reason other than some magical/mystical explanation that includes the microscopic organisms in the starter somehow behaving differently in larger quantities of consumable material, which I will not buy.
I would really like to believe that there's a reason to produce hundreds of pounds of levain each year beyond what I actually need, since I really respect these books and their authors; they've improved my baking dramatically. I don't want to make pancakes or english muffins or compost. I want to make bread.
So what am I missing?
Thanks in advance.