The lowdown on sourdough

Step-by-step guide to the perfect sourdough bread

olive cookery writer and ex-baker Adam Bush shares his bread-making expertise. Learn how to create your own starter (no yeast needed), then how to craft the perfect sourdough loaf with our step-by-step guide

Want to make your own sourdough bread? Check out our sourdough starter recipe and sourdough bread recipe guide with expert tips from our sourdough baker. Baking fresh bread is one of the most rewarding experiences a cook can have. Making your own sourdough takes this experience to the next level, as you get to control every part of the process, using the simplest of ingredients – just flour and water.



One of the most important elements in baking sourdough at home is having a good starter. You may have heard stories of people jealously guarding and nurturing their starter, naming it, carefully feeding it and controlling the temperature and environment it lives in. In truth, this makes it sound a lot more complicated than it is.

The lowdown on sourdough

A starter is simply a mixture of flour and water – combining the two activates the wild yeasts and bacterial spores naturally found in flour. And, given time, these microorganisms become strong enough to make the bread rise.

All starters follow the same process. Yeast eats sugar present in the carbohydrates (the flour). This creates lactic and acetic acid (the sour taste in sourdough) and carbon dioxide. The latter gets trapped in the dough’s gluten structure, creating little bubbles that make the dough rise. Every time the starter is fed, this little army of yeast gets stronger and more populated. The stronger the starter, the better the bread.


strong white bread flour 25g

rye flour 25g

warm-to-the-touch water 50g

Mix 25g strong white bread flour, 25g rye flour and 50g warm-to-the-touch water (weigh it for accuracy) well, and leave, loosely covered, for 24 hours at room temperature. There may not be too many bubbles at this stage. The next day, add 15g more of each flour to the starter and 30g of water. Mix well and, again, leave loosely covered at room temperature for antoher 24 hours. Repeat this second step every day for the next four days and the starter will begin to bubble and rise more with each feed. A day after the final feed, the starter is ready to use.


A glass flip-top jar makes a good vessel for a starter – when it’s out at room temperature, the lid can be left slightly open to release excess gas, and then shut again while it’s in the fridge.

I use a mix of strong white bread flour and rye flour for feeding my starter. Strong white bread flour has strong gluten bonds, meaning it can sustain its structure as it bubbles, while rye flour has a high sugar content, so the starter is well fed. Good digital scales are a must when feeding the starter, to ensure you are feeding it with exactly equal parts flour and water.

The lowdown on sourdough


When not using the starter, it’s best to keep it in the fridge – this drastically reduces its activity. If I’m not baking at all that week, I will feed the starter with 50g flour and 50g water, and put it back in the fridge. This will give it enough food to keep it alive while it’s not being used.

As long as its been kept in the fridge your starter should be revivable after several weeks of neglect. No need to drop your starter into a hotel (these really do exist), just pour off any clear liquid, give it a feed and leave at room temperature. If after one feed you’re not getting many bubbles, feed again and leave it out. If there’s still no movement, it may be time to make a new starter.

When preparing to bake a loaf, the night before I need to make my dough I will remove my starter from the fridge, feed it, and leave it out at room temperature to bubble up and get its strength back.

Remember to always feed the starter with more flour and water than is needed for the bake, so that there is enough left over to be used in the future.

The lowdown on sourdough


Commercial yeast was developed in the 19th century, during the industrial revolution, to help feed a booming population. This strand of yeast was favoured for its rapid rising properties, which drastically reduced proving times before baking. This put bread on tables faster, with more control over mass-produced uniformity.

With this development though came a reduction of flavour in bread. A faster, aerated prove also means lots of air within the bread – most obvious when a standard slice of white bread can be squeezed down to a square-inch dough ball.

There is also little or no acid production in this type of bread making, so the loaf lacks the ‘tang’ that sourdough lovers know so well. This acid also means that sourdough bread keeps for longer, preventing the loaf from going stale so quickly.

The lowdown on sourdough

Sourdough is slow bread. It takes time, practice and love. Creating a starter is sometimes a little unpredictable, but with plenty of practice the results can be amazing.


Now we’re going to turn that starter into beautiful bread. Hopefully your starter is raring to go and you’ve got pats of salted butter on ice – let’s make bread!

Sourdough, part 2


This sourdough loaf is one of my favourites to bake. Spelt is an ancient grain that has been cultivated since around 5,000 BC but over time has been replaced by high-yielding ‘strong’ wheat varieties. Spelt contains less gluten but has a much stronger flavour and is more nutritious than normal wheat.


• a big bowl – buy here

• a set of digital scales – buy here

• a dough scraper – buy here

• a banneton or proving basket (available from or

• a sharp pair of scissors/knife/lame (a blade for scoring the loaf) – buy here

• a cast-iron pot with a lid – buy here

Sourdough, part 2 equipment


Mixing some starter, flour and water together, with a spoon or by hand, creates a ‘young levain’ and simply involves taking some of the old, strong starter – that is likely very sour – to start working on a new batch of flour and water. This utilises the strong colony of yeast and retains a little bit of its sourness while still keeping the natural sweet flavour of the flour.

My basic recipe is:

sourdough starter 40g

strong white bread flour 15g

rye flour 15g

water 30ml, warm to the touch

Once combined, leave at room temperature, covered with a clean tea towel. Do this the night before you want to make your bread, so that in the morning the levain is beautifully frothy and at full strength. At this point it’s well worth feeding your remaining starter, too, as you’ve likely reduced it substantially to make the levain.

Sourdough, part 2


This is when the magic of sourdough happens. The shaggy, lumpy dough – which is created by combining the below ingredients – will soon become a smooth, shiny, stretchy, buoyant mass. Again, time and patience are key. This is the highest maintenance part of baking sourdough: you need to nurture and encourage the dough with your hands. Having said that, sourdough is known as a ‘no-knead’ bread – when left to ferment, the dough’s gluten bonds will align themselves.

levain 100g

water 380ml, warm to the touch

strong white bread flour 400g

wholewheat spelt flour 100g

fine sea salt 12g

Start by putting the levain into a large mixing bowl and then pour in 350ml of the warm water. Mix well with your fingers to distribute the levain, then add the flours and mix really well with your hands. You will learn most about the different stages of your bread by getting your hands on the dough. Even professional  bakers who mix dough in 50kg dough mixers, reach in and touch, stretch and feel the dough. Open up your fingers and use your hands like whisks to really mix the flour, levain and water together well.

Leave this to rest for between 20 minutes and 1 hour, covering the bowl with a clean tea towel. This stage is called the autolyse and comes from the Greek for ‘self-digestion’. This is why sourdough doesn’t have to be kneaded, as the gluten structure forms itself here, doing all of the hard work. If you’re particularly short on time, even a 15-minute rest will make a difference.

Tip in the salt and remaining 50ml of water (adding it after the autolyse with a bit of water ensures the dough develops better elasticity) and, with wet hands, mix the dough really well. Breaking the gluten bonds now will allow them to reform even stronger. This is called bassinage and will ensure the flour absorbs as much water as possible and is highly hydrated.

The next step is called the bulk fermentation. Leave the dough covered with the tea towel and, every 45 minutes, ‘stretch and fold’ the dough. Wet your hands, take one side of the dough, stretch it up (being careful not to tear the dough) and fold it over on  top of itself. Turn the bowl 90 degrees and repeat, doing this six to eight times. The dough will ‘tighten’ and become less slack. Repeat this every 45 minutes for 3-4 hours (so 4-5 times in total). Every time the dough is turned it should have more air bubbles and also, toward the end, feel noticeably lighter.

Next is the bench rest. This is when the dough can be encouraged into a regular shape, creating tension so that it has the strength to stay ‘bread shaped’ when baked, as opposed to flattening into a pancake.

Flour a clean worksurface really well and tip out the dough. Using a dough scraper, fold the dough up and over on itself, similar to the stretch and fold method but just folding this time. Do this 4-6 times, and again the dough will tighten and hold its shape better. Add more flour to the worksurface if the bread is sticking.

The dough should be relatively round now, so leave it to rest for 10-15 minutes – expect it to flatten a little.

Sourdough, part 2


Start by flouring the banneton or proving basket. In this method I use a cold proving technique, which means putting the loaf into the fridge overnight or for several hours. This increases flavour, as the acid production is still happening but with little gas production, meaning a more stable loaf. The cold will also make the loaf set its shape in the banneton, giving a headstart for a beautiful plump loaf once baked.

Flour the top of the loaf, then use the dough scraper to carefully flip it over,  so the floured side is on the worksurface. Lightly shape the loaf into a rough rectangle and fold the edge furthest from you up and over the middle. Do the same with the left-hand edge, the right-hand edge and the edge nearest to you. Work quite quickly to keep the shape of the loaf. Lift up and put straight back into the banneton, folds facing up, and into the fridge to chill. Again, if you’re short on time, just 1 hour will help the dough keep its shape better.

Sourdough, part 2


Heat the oven to as hot as it will go and put a lidded cast-iron pot in while it heats, for around 45 minutes. This will help to recreate the conditions of a baker’s oven. In the first part of cooking, bread needs steam because a moist environment means bread will rise to its fullest and prevents the crust from forming on the loaf, so it can keep rising. Cooking the bread inside a lidded cast-iron pot for the first part of cooking traps the naturally produced steam.

The faster the loaf comes out of its banneton, is scored and in the oven, the better. So get yourself well prepared by having a clean chopping board or cake slider (in baking terms this is called a peel) in front of you, so you can score the loaf on this and then carefully slide it into the pot.

Also have your scissors/knife/lame (blade) close to hand. The reason to score a loaf is to direct it where and how to rise. As the gasses expand inside the loaf, they will tear the outer structure – without scoring, the loaf will often tear on the side or near the bottom, which will ruin its look.

Have a good pair of oven gloves and a bowl of polenta to hand. Scattering polenta on the chopping board allows the loaf to slide off easily into the pot.

When fully heated, remove the pot from the oven and take off the lid. Turn the oven down to 260C/fan 240C/gas 9. Remove the loaf from the fridge and scatter polenta all over the chopping board, the bottom of the pot and the loaf. Turn the loaf out onto the chopping board (it may take a little coaxing) and score the top – I often just cut a square. Slide the loaf into the pot, put the lid on and return to the oven for 20 minutes.

Remove the pot from the oven and take off the lid. Return to the oven without the lid for another 20 minutes. Remove from the oven again and tip out on to a wire rack to cool. Then enjoy your delicious sourdough creation, slathered with butter.

Bread baking is a hugely rewarding process, but it can be quite unforgiving. Even as a professional baker, baking 250 sourdough loaves in a day, it can be unpredictable – there are many variables and factors that can influence a loaf. If your loaves aren’t as good as you’d hoped, keep trying. The more you bake, the more success you will have. Once you’ve baked the loaf of your dreams, harnessing the power of flour, water and salt, you’ll be hooked, just like me.

Sourdough, part 2


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