The secret to any great loaf of bread is a pre-ferment, or starter. This could be a quick one-day-old poolish made with flour, water and a pinch of yeast, or a proper sourdough which is a culture of wild yeast. A starter provides a depth of flavour to the bread, but, arguably more important, it gives it a fantastic texture. A mature sourdough has had plenty of time to develop a complex gluten network over a period of several weeks (or months, or years!), which is simply unobtainable with a standard loaf that’s only proved for a few hours.
This sourdough starter will take at least five days to make, but from that point it’ll last indefinitely, provided you look after it. After five days, you’ll be able to make a decent loaf of bread with it, but if you leave it for longer; two or three weeks, say, you’ll get a far superior flavour and texture.
This is a true wild yeast; an actual living organism. I think there’s something magical about being able to extract this stuff from thin air, literally. Wild yeast particles are everywhere; all we’re doing is creating an ideal environment for them to grow and multiply by providing them food (flour) and water, at an optimum temperature.
The temperature is quite important in the initial few days as the sourdough gets established, however, once it’s going strong you can keep it in the fridge which will slow it down so you don’t have to feed it every day; once every 4 days will suffice instead of every day.
Measure 200g of strong white bread flour and 200g of lukewarm water into a bowl, and mix thoroughly. Cover lightly with cling film, ensuring to leave some gaps for it to breathe, and leave in a warm place, ideally 24C, for 24 hours.
There should now be a few bubbles on the surface of the sourdough. In a separate bowl, mix together another 200g each of flour and water. Add 120g of the 24h sourdough and mix thoroughly. Discard the remainder of the old sourdough. Cover lightly again, and leave for another 24h.
The 48h old starter should now have more bubbles on the surface, indicating increased yeast activity. Mix another 200g each of flour and water in a separate bowl, and add 120g of the 48h sourdough. Cover lightly, and leave for 12 hours in a warm place.
Repeat Step 3 several times, until the sourdough is 5 days old. With each “feeding” you should notice increased yeast activity. From this point on, you’ll only need to repeat the feeding process every 24 hours, instead of 12, or about every 4 days if you keep it in the fridge.