For the starter: 120g strong wholemeal flour20g strong white bread flour 120ml water, at room temperature
For feeding over 10 days:10 x 70g strong wholemeal flour10 x 20g strong white bread flour10 x 75ml water at room
Mix the first day’s ingredients in a very clean small bowl with a scrupulously clean fork until you have a solid, stodgy batter. Pour the starter into a clean plastic container at least four times its volume and cover it loosely with a lid so it still lets in a little air. There are yeast cells all around and, hopefully, some of them will latch on to this mix. Put the starter in a cool room – but not in the fridge, a cupboard, or any other enclosed space. After one day, feed the starter for the first time.
Weigh out 150g of the starter and discard the rest. Feed the remainder with the 70g of wholemeal flour, 20g of strong white flour and 75ml water. Put back in its container and cover it loosely. Leave it to rest for another day.
Repeat each day, for 10 days or ad infinitum – literally. Your sourdough could live for ever, unless you forget to feed it – in which case it will die. If you’re going away for a few days, you can move it into the fridge, where the cooler temperature will slow down the work of the yeast and allow it to survive for two days without you. Be sure to bring it back to room temperature before its next feed.
It will take between 7–10 days for your mixture to grow into a vigorous sourdough starter. As time passes, you should see that something is happening. It should bubble gently more and more with every passing day, and the smell should be fresh and yeasty, with a hint of alcohol. If the scent is unpleasant, with sour, vinegary notes, throw it away and start again – unfortunately, this is a sign that the wrong bacteria have colonised it.
After 10 days, if both you and your starter are happy, together you’re ready to make the loaf of your life – a loaf that is the cornerstone of every artisan bakery in France and beyond. Weigh out your 150g to keep feeding as a starter and, instead of discarding it, use the rest to bake sourdough bread.