The magic behind sourdough

Sourdough is a genuinely good alternative to processed bread, and it is not difficult. I have been making it since I was fourteen, so if I can, anyone can.

What sourdough actually is

Sourdough rises through natural fermentation. What sets it apart is the starter: a mixture of flour and water that captures wild yeast and beneficial bacteria from the environment and ferments into a bubbly, tangy culture. That culture is the leavening agent.

There are two stages. First you build the starter, letting flour and water ferment over several days until the wild yeast and lactobacilli have taken hold. Then you make the bread — starter, more flour, water and salt — and give the dough a long, slow rise, usually overnight. That long fermentation is where the flavour comes from.

The result is a chewy crust, an open crumb and a distinct tang from the lactic acid the bacteria produce. It is also more digestible than conventionally leavened bread, and better tolerated by a good number of people.

Why the long ferment matters

• Digestibility. Fermentation breaks down compounds — gluten and phytic acid among them — that some people struggle with.
• Mineral availability. Phytic acid binds minerals and blocks their absorption. Breaking it down frees up zinc and iron.
• Blood sugar. Slow fermentation appears to produce a lower glycaemic response than fast commercial bread.
• Nutrient availability. B vitamins, minerals and antioxidants become more accessible.
• Fewer additives. Flour, water, salt, starter. That is the whole ingredient list.

Commercial yeast is not inherently bad, but rapid fermentation does not do any of the above. It raises the loaf and stops there. Refined white flour compounds the problem: the milling that produces it removes the bran and germ, taking the fibre and most of the nutrition with them.

A rustic loaf

You can buy a starter or make your own. Feeding it is simple — equal weights of water, starter and flour, so 200g of each. What you take out before feeding is the discard, and it has plenty of uses of its own.

One note: converting a yeast recipe to sourdough is fiddly. Look for recipes written for sourdough instead.

Ingredients

• ½ cup active starter
• 1¼ cups warm filtered water
• 3 cups plain flour
• 1½ tsp salt

Day one

• Combine the starter and water in a bowl and mix with a fork until mostly dissolved. Add the salt and stir again.
• Add the flour and mix until a ball forms. Knead it briefly in the bowl. It will look shaggy — that is fine.
• Cover with a tea towel and rest for 30 minutes, then knead again. The texture should now be much smoother.
• Oil the dough and the bowl, cover with cling film touching the dough so it cannot form a crust, put a tea towel over the top and leave it on the counter overnight.

Day two

• Turn the dough onto a floured surface and fold the edges into the centre in a circle. The underside should be a smooth dome.
• Flour a proving basket generously — or the same bowl with a floured tea towel in it — and place the dough folded side up, dome side down. Prove for two to three hours.
• Heat the oven to 230°C. Flip the dough onto baking parchment, dome side up, score it, and lower it into a hot casserole dish.
• Bake 20 minutes with the lid on, then 30 minutes with the lid off. If you have doubled the recipe, 30 minutes each way.
• Let it cool for at least 40 minutes before cutting. This is the hardest instruction on the list.