there's no need to add even more water and flour every day, whether you're you're using a commercially available package of sourdough yeast or trying to start one from the natural yeasts floating around in your kitchen or those located on the skins of potatoes, fruits, grains, etc., etc.
just start off with enough flour and water to make several cups of batter about the consistency of pancake batter. either use the package of commercial sourdough yeast, or add some potato peelings, organic dried corn, organic apple peels, grape peels, etc. or simply just let it sit out in your kitchen. store-bought sourdough yeast will start working about as soon as any regular yeast. peelings, etc. or pot-luck will take days, maybe 4 or 5 or a week or so. eventually it will start bubbling, all you have to do at that point is to decide if it smalls pleasantly piquant, or simply foul.
if you decide it's ok to use, take out a cup or two to start a dough, and replace enough flour and water to make up what you used. if you're planning on using the starter within a day or two, let it sit out at room temp. over-night. if you won't use it till like next weekend, just put it in the fridge.
I quess everybody does things differently. I never used a commercial sourdough starter. The first one I did was started with water, whey and white flour. used 2 cups of liquid to 2 cups of flour. I remember now that I had to leave that mixture to start to ferment for a number of days, before touching it. I dont remember now, how many days it was, it may have been about 3, but anyway after it starts to bubble, I needed to check it to make sure that it was smelling sour and not spoiled. After it started to ferment, i stirred it down and transferred it to a clean container along with one cup of flour and one cup of water more. I did this in order to insure that the yeast would have more starch to feed on, rather than on itself which may make it spoil. For two more days I did this, and by then, I had 5 cups of sourdough starter. I took out one cup, put in a jar in the refrigerator, and used the rest to continue with the recipe.
Everybody has a different way of doing things, but this worked for me. I just use the refrigerated starter now, and add 2 cups flour along with 2 cups water, let ferment overnight. remove one cup back in the refrigerator and start again. I get very good results.
I have a rye starter, that I made with crushed grapes, water and rye flour. It fermented and was ready to use in just 3 days because rye seems to ferment much faster than wheat. I saved some starter and reuse it, but I read that many bakers dont bother to save the rye starter because it ferments so quickly.
I made a really good dark seeded rye last week. Does anyone have any recipes for light rolls using a sourdough starter?