About feeding your sourdough starter:
I know that some people will disagree with me and that's ok. Here's the thing. I never take my sourdough starter out of the fridge just to feed it. Never. I make bread with it probably about twice a month, but I've gone as long 4-6 months without ever touching it. It just stays cold in the fridge, waiting for me to bake again. I use a pint container, which holds enough starter to keep itself happy in my fridge for quite a while.
Every time I use the starter, I'm really making a brand, new batch of starter along with making my bread dough. I pour all of my starter into a big bowl and set the starter jar to the side to be cleaned thoroughly. I add some lukewarm water to the starter in the bowl and enough white flour to make a "batter," similar in looks to thick, pancake batter. Once in awhile I might also add a teaspoon of white sugar to give it s jump start, but I don't do that very often. I stir it up, cover it with a dishcloth and set the bowl in a warm place for 1-2 days. It will start bubbling up...not a lot, but there should be some bubbles forming in it from the yeast activity. Then, I take my clean jar and fill it up with some of the "batter" from the bowl. The "batter" (aka starter,) that is left in the bowl is what I use for my loaf of bread.
When I'm done, the jar of starter goes back into the refrigerator to be used for the next loaf of bread. The yeast will go into hibernation and rest easy in the cool fridge, waiting patiently for you. Don't worry if your starter separates. That's just because the weight of the flour is heavier and settles to the bottom, leaving the watery liquid on top. It's still good. Just stir up, if you feel that you must.
Yeasts are everywhere around you. You really can't kill all of the yeast in your environment, so don't even try. However, molds are another story. You don't want mold in your starter. That's why you always restart it in a clean jar, before you put it back in the fridge. If you do have to start over, it's no biggy. Just mix some flour and water together and set it out in a warm place, in a covered bowl, for a few days. The yeast from the air will find its way to your mixture and start to grow. If you want to go the easy route, add a package of baking yeast to the mixture to guarantee that the commercial yeast will dominate and take over.
This is easy. Not complicated at all.
