I have conquered sourdough baking! I successfully made a sourdough starter from flour and water and have been using it to make bread with no added yeast. Here's how.
2 wide mouth quart Mason jars
I use 100% wheat flour, the kind often called bread flour. I think you could use all-purpose, but I haven't had good luck with it in the past.
Put one cup of water and one cup of flour in the Mason jar. Stir it up. Let it sit on the counter, covered loosely. The next day, stir it up and pour out half. Add a half-cup of flour and a half-cup of water, stir it again, and pour the whole lot in the second jar. Cover it loosely again and put it back on the counter, then wash the first jar. Keep it someplace between 70 and 80 degrees, if possible. Too cold and it's too slow, and anything much more than 100 degrees will start to kill it.
Keep repeating the process of discarding half and adding new flour and water for several days. You don't have to switch to a new jar each time - it just looks tidier. Do switch every few days though. After a few days, you'll probably see some separation when you tend to the resting starter, and it will begin to smell like sour beer. The golden brown liquid on top is hooch, and it's alcohol produced by the wild yeast growing in the starter. That's good - it means the yeast is getting strong!
After a week to 10 days, the starter will probably be strong enough to make some bread. I make three loaves at a time but you probably won't want to do that to begin with because if your starter is too weak it's a lot of bread to waste! Here's a recipe for one loaf.
The night before you want to bake, pour the cup of starter into a clean jar and add a cup of water and a cup of flour. Cover it as usual. The next morning, combine 1 and 1/3 cups of the starter with 2-3 teaspoons of sugar, a heaping teaspoon of salt, a tablespoon of oil and finally 2 cups of flour together in a large bowl. Stir it up as well as you can, then scrape it out on a clean floured surface and knead it for a few minutes. You may need a bit more flour. If you know how bread dough *should* feel, use your best judgment. If you don't, then just go with the 2 cups. It's pretty forgiving stuff. Save the extra starter - that's to keep the cycle going. Put a half-cup of it in a clean jar and add a half-cup flour and a half-cup water, as usual.
Put it back in a clean oiled bowl and cover the bowl. I usually just set a dinner plate on top of the bowl. Then put it in the oven (with the light on, if your oven has a light) and let it sit there until it rises to around twice the size as before.
This can take a LONG time. Much longer than a quick yeast rise. Just saying.
When it has risen, take it out and punch it down, then put it in an oiled loaf pan if you like, or shape it into a round or oblong loaf on a baking sheet if you don't, and cover it with a damp cloth. DON'T USE TERRYCLOTH. Use something smooth, like a floursack towel, or a piece cut from an old tee shirt. If you use terry the loops tend to catch in the dough and it's not pretty. If you don't have that you can use clear plastic wrap.
Then put it back in the oven and let it rise again to about twice the size. When it's risen, take the cloth off and turn the oven to 350F. Let it bake about 30 minutes. When you take it out the hardest part is waiting for it to cool.
If the dough just doesn't rise, keep feeding and dumping the starter and try again in a few days. Once you get the starter happy, you can keep it in the fridge and you only need to feed it about once a week.
If you don't refrigerate it, this can generate quite a bit of waste as far as pouring out the starter goes. Once you have a feel for how much starter you need to make bread, you can save a much smaller amount back, a half-cup or even less, then make all the finished amount of starter you need the day before you bake. So if you need 5 cups of starter to make the batch of bread, and you have a half-cup of starter to begin with, add water and flour in equal measure until you get to 5 and a half cups the night before. This should work with reasonable amounts of starter. I think you'd have to make a massive amount to dilute it enough to need more than 12-16 hours pre-baking.
If anyone sees any errors please email me - the address is in the sidebar.