How to make a sourdough starter?
I use the method described in William Alexander's delightful "52 Loaves". It involves first capturing the yeast using apple peel plus a cut up apple in an open container with water, then using that liquid to create the starter. It's done on the counter, and you stir it fairly regularly, to incorporate air, during the initial period of flour + water + ambient yeast. It creates a positively delightful, not sour but beer-y, fermented smelling starter. I've had mine for about a year and it creates the most amazing artisanal breads. (After a few days, it goes back into the fridge, but it's brought out the night before I need to use it for feeding and sitting at room temperature. I also like to bring it to room temperature before incorporating it into my dough.) There was a recent post on this topic -- not so much on starting, as on maintaining -- that provides a wealth of information in the comments. Please see: http://food52.com/blog...
Have fun! ;o)
I have used a method similar to Antonia's, but with a bunch of organic grapes rather than an apple. It made a really wonderful starter.
Nancy Silverton's "Breads from the La Brea Bakery" also details making a starter with grapes, flour and water and how to maintain it. Plus it makes absolutely wonderful bread.