Sourdough is bread with a natural leaven i.e no yeast. Dating back to 1500BC, it is the more than likely to be the original leavening available for bread baking. This is biblical bread.
As sourdough uses no yeast you need to create your own leaven or 'starter' of flour and water, and feed it for several days in the hope of catching the natural yeasts in the air and breeding them, as they breed they give off carbon dioxide, carbon dioxide produces a bubbly mix which (hopefully) will help your bread rise.
I cheated a little by making my starter on my bread baking day, hoping that the yeast in my dough (and therefore in the air in my kitchen) would encourage the natural yeasts in my sourdough to breed.
I used Hugh Fearnely-Whittingstall's recipe from 'The family cookbook'
Measure 3 heaped tablespoons of organic strong white flour into a large mixing bowl. Add a tablespoon of organic wholemeal flour. Tip in the juice of half a orange and enough lukewarm still mineral water or rain water (I used boiled and cooled tap water but Hugh says not too) to make a thick stir-able dough - about 4 tablespoons.
Stir this mixture and then beat it with a wooden spoon or a whisk for a few minutes to drive air into it. Cover the bowl with clingfilm and set it aside in a warm place.
Check for frothy bubbles- signs that your mixture is 'breeding' and therefore producing carbon dioxide gas.
Beat in another 4 tbsp of white and wholemeal flour just as before, plus 4 tbsp of water.
Cover with more clingfilm and leave overnight.
Hopefully the dough will be quite active - bubbling furiously and rising up the bowl.
Beat in another 4 tbsp of flour and 4 of water.
Cover and leave overnight.
Tip in 6 tbsp of organic flour - 5 of white and 1 of wholemeal. Stir well and allow the dough to rise again but just for 2-3 hours this time.
Take out 2 tbsp of dough mix and put in a small bowl and put to the side. (This is now your starter for your next loaf.)
Tip in 125ml water and 300g organic strong white flour, plus 2tsp of salt and enough warm water to make a smooth dough.
Mix, knead, prove and bake (200c for 25 - 30 Min's) as you would any other loaf. This loaf will take much longer to rise than a regular loaf and won't rise as much either.
fresh from the oven
The dough was great to work with too, the finished bread was delicious, it wasn't as heavy as I'd expected it had a lovely texture and chewy crust....with a slight sour tang, delicious!