Acabei de fazer a mesma pergunta aqui: Por que jogar fora tanto starter de massa azeda? Tartine Book no. 3
Encontrei uma resposta muito boa online. Na verdade, seria mais fácil e mais barato jogá-lo fora, já que você não precisa comprar tanta farinha orgânica no futuro para alimentar seu motor de partida. Imagine comprar 5 xícaras por dia para alimentar sua partida, quando você pode usar apenas 100 gramas!:
During the "initial" development - and by this I assume we're talking the first several days of your brand spanking new starter, what you'll be throwing away is likely not even "starter" but rather flour soup wherein there's a fairly good chance you're also growing a few less-than-desirable cohabitants. This would explain why you'd want to chuck it out rather than use it. You also cut back on your starter so you don't end up with gallons of it since quite early on you do begin to make your feeds at a ratio of 1:1:1 or 1:2:2. For illustrative purposes, let's follow the 1:2:2 ratio and just assume we're using cups (easier to visualize) although you really would be weighing, of course. So let's say on day 1 morning feed, we begin with a half cup of starter. Half a cup sounds like nearly nothing, right? To that we'd then need to add twice that amount of each water and flour, so we add 1 cup water and 1 cup flour for a total of 2.5 cups. Still not that bad. Day 1 evening feed, we're not reducing so we need to add to our 2.5 cups of starter 5 cups water and 5 cups flour for a total of 11 cups. Set it on the counter, hope it doesn't overflow everywhere and go to bed. Day 2 morning feed, we're still not tossing away so to our 11 cups we have to add 22 cups of water and 22 cups of flour. We now have 55 cups of starter or about 3.5 gallons. Remember, this is only the third feed and we started with just a measly half cup yesterday morning. At tonight's feed, we'll have 312 cups or 19.5 gallons of starter. Just enough to fill up four of those white Home Depot buckets although you'll want at least eight of 'em so the starter can double in size. By morning of day three, you can fill your bathtub, if it holds 97 gallons; it very well may not, and definitely won't hold the expanded starter. By afternoon, you'll also be borrowing an additional four neighbour's tubs for your 488 gallons. How soon before you need to move this out to a local swimming pool to continue? Well, by the end of day five, you'd be the proud owner of 305,175.8 gallons of starter. Or 4.8 million cups. Seriously. An Olympic size pool is about 600,000 gallons. By the morning of day six, you can fill two and a half of them, with leftovers. And it hasn't even been a full week yet. And that's why you cut your starter back down to a manageable amount each time. It's a lot cheaper to toss a little bit out than to keep it and feed it.
Fonte: link