I've been making sourdough bread for about 3 years, and the site I used that I found very helpful was "Breadtopia" (
http://breadtopia.com/sourdough-no-knead-bread/), and I use their "no knead" recipe.
The site has a good link on making starter here:
http://breadtopia.com/make-your-own-sourdough-starter/
To summarise what they say - unsweetened pineapple juice works really well; it apparently has enzymes in that mean the natural yeasts in the flour and air will take to it, but the nasty stuff that would make it go off can't survive. The recipe on the site says to use wholemeal flour, but I used strong white bread flour for mine, and it worked fine. It takes about a week before the starter really gets going, so persevere! If you're going to be making mainly white sourdough, use strong white bread flour for the starter; if you'll be making wholemeal, use wholemeal for the starter.
Once you have your starter, it's fairly robust. I keep mine in the fridge, and once a week (though it doesn't matter if you forget and leave it a fortnight) I pour all but 1 cup (250ml) away down the sink, then pour the 250ml of starter back in my container, add the same amount of water, and add strong white bread flour until it's a slightly runny and put it back in the fridge. There are all sorts of arguments about the correct level of "hydration" - some say the starter should be the consistency of toothpaste, but I find a slightly runnier starter makes it easier to pour and easier to see if it's got any bubbles in it (which means it's still alive).
As for letting the starter do its thing overnight, I don't bother, because the no-knead recipe I use has an 18 hour rising time anyway. Here are the steps I do for a small sourdough loaf:
1. Take my starter straight from the fridge, pour about quarter of a cup of it into a bowl (60ml or 4 tablespoons). If there's plenty of starter left, I put the starter container back in the fridge, but this is also a good opportunity to feed the starter again (see above).
2. Add one cup of water (I just use tap water at room temperature - if your water is heavily chlorinated, might be better to boil some water first and let it cool down so it doesn't kill the starter, but my tap water seems fine) to the starter in the bowl and stir it in.
3. Add about two cups of strong white bread flour and a teaspoon of salt to the bowl, and stir until you have a sticky mess. The dough should be much stickier than for standard bread - too sticky to knead, but only just too sticky. So at this "porridge" stage, add a little more flour until you get to that "too sticky to knead but only just" stage - the sticky mess should come away from the side of the bowl, but it shouldn't be firm enough to knead.
4. That whole process should only take a minute or two - no heavy kneading required, as the very slow rise will do that job for you. You simply cover it with a damp cloth and leave it for 18 hours. Your mileage may vary - 18 hours is about right in the UK in a room at about 20C. If you live in a warmer climate, 12 hours will probably do. However, as sourdough is quite lazy and slow, it's quite forgiving. An few hours extra won't hurt.
5. After 18 hours, it's time to "stretch" the dough. When making bread with commercial yeast, you'd knock the air out the dough at this stage, but with sourdough we don't want to undo that 18 hours of work the yeast has done! So you gently scoop out the dough onto a floured board, with floured hands, and gently stretch the dough. It will be quite stretchy at this point, a bit like Blu-Tak, and stretch it at all four corners until it's thin enough to be translucent. I aim for a sort of square "pane" of dough covering my board. Then gently fold the left hand side over about 2/3 of the way, then the right hand side 2/3 of the way covering that, then do the same to the top and bottom sides. What you'll have now is a sort of slightly puffy ball of dough. Put that into an oiled bowl, cover, and leave for about 2 to 4 hours. It won't double in size like an ordinary loaf - in fact, you may not notice much difference at all during this time.
6. The secret of crusty sourdough and making it rise is to put it in a VERY hot oven in a container. I have a set of steel saucepans that are ovenproof up to 250C, or you can use a heavy duty casserole dish, or a terracotta cloche. The important thing is to heat that up first - so I put the cold saucepan, empty, in the cold oven, and turn the temp up to 250C. Once it reaches temperature, take out the saucepan (250C is VERY hot so be careful, even with oven gloves you need to be careful not to burn yourself), sprinkle a little matzo meal in the bottom, or semolina (to stop the dough sticking), and very very gently scoop the dough out of the bowl and drop it into the very very hot pan.
7. If you like that artisan "split" at the top of the bread, very quickly slash the top of the dough with a sharp knife, but this isn't essential. Put the pan back in the oven and cover it with a baking tray to stop the top burning. You can also put a small pan of water in the oven for a crustier loaf, but it's not essential. Cook for about 20 minutes, then take the tray off the top of the pan and cook for a further 10 minutes.
8. Carefully remove the pan and turn it upside down, and tap the bottom of the bread to see if it sounds "hollow" - if it doesn't, put the loaf back in the oven (no need for the pan now) for a few more minutes, but I find 30 mins is fine for a small loaf.
It's very tempting to rip it open and eat it hot, but sourdough really does benefit from being allowed to cool. If you eat it hot, the inside will still feel pretty sticky and doughy. That hour or two cooling helps the bread settle, so resist temptation!
