Publisher's Synopsis
It is surprisingly easy to bring new life into the world. Put a few tablespoons of organic flour (rye if you can get it) in a jam jar. Stir in enough warm water to make a thickish paste, cover with kitchen towel and put it somewhere away from radiators and other heat sources. Leave the mixture for up to a week, stirring occasionally if you can be bothered. If a boozy-smelling liquid forms on top, swizzle it back in. (If nothing has happened by the seventh day, chuck the lot and start again.) Eventually, little bubbles will form throughout. Congratulations! You have mastered the secret of creation.
Put another way, you have made sourdough starter. Your flour and water have been colonised by wild yeast, which is now eating, breeding and producing carbon dioxide. Once upon a time, this was what bakers used to make almost all of their bread rise, and it is still essential if you like your loaves to be full of flavour and interestingly shaped holes. That's the thing about sourdough: even "foolproof" recipes will sometimes produce bread that is misshapen or plain ugly. But it will still taste better, and last longer than almost anything you can buy.