I'm very new to all this sourdough stuff and just trying to get my head around a few things. Why, when refreshing the starter, do some people recommend discarding some of the starter? Is this simply to keep the quantity of starter under control or does it have an impact on the chemistry of the starter? Any thoughts gratefully received!
If you don't discard when you refresh you will soon end up with a bathtub of starter by doubling each time.
Ford
Some folk go overboard quantity wise .
At most , my starter containers carry about 300mil. tops , and the flour and water is about a third of that . If and when I remove some , it is about three or four tablespoon's worth . Soon you will be using the removed portion to make dough .
The reason for removing/discarding is because you are feeding a baby starter small drinks and meals more often than the adult stater will need .
When your starter is up and running , discarding may well become a thing of the past .
Making a starter for the reason Ford said. After which a maintenance schedule can be worked out with no discard as PatMax said.
Just realised I haven't added to this conversation but started to type and read the previous comments at the same time.
The larger the quantity of starter, the larger the feed. For me, I can keep, say, 150 grams of sourdough starter, and when it needs fed, I can just discard 100 grams and feed it 50 grams flour to 50 grams water. If I hadn't discarded, I would have 150 grams of starter, which would mean that I would have to feed it 150 grams of flour to 150 grams of water to keep that 1+1+1 ratio. Discarding makes it much more manageable- and cheaper when I don't have to feed it so much flour! If I need a larger amount of starter, I may wind up not discarding, but usually that's what a levain is for!
Quantity is one aspect, but the other aspect is the resulting make-up of the starter--as you suggest, the chemical composition that results. Let's say I only bake bread weekly, and to keep the smooth flavors, I keep my starter outside of the fridge. After 6 days of feedings, I'm going to have less than 20% "fresh" starter when I go to bake bread on Wednesday. I only need 200 grams or so for a couple loaves, but I'd be pulling lots of old dead yeast and concentrated lactic and acetic acid when digging into 6 days worth of refreshes.
You can probably get away with the quantity of vigorous yeast left in that mix for your rise, but the concentrated acids (think: that concentrated smell after leaving a starter untended for four or five days) will definitely make your sourdough quite a bit more sour. That may be to your taste, which is perfectly valid. But for comparison, I refresh daily and discard and/or make pancakes with the spent starter, using only recently refreshed starter in my breads. The acid still comes through, but it's not overpoweringly sour.
Because I'm basically removing all but a tablespoon or so when refreshing, I don't actually refresh daily. I refresh every couple days unless I'm specifically timing the refresh for a baking day.
maintain a starter at all. Most folks don't like sour bread and do everything they can to make their SD bread with as lttle sour as possible. White flour starter kept on the counter and maintained daily do this quite well. But for those who donl't want to chained to a starter, its maintence and discards and like their bread sour, hearty and healthy - there is a better way. It makes great white SD bread too! Happy baking
No Muss No Fuss Starter