How to make a sourdough starter

By BBC Maestro

Sourdough has risen to fame in recent years. From its featured appearances on weekend brunch menus to its front-row seat in bakery windows, it has built itself quite the community of dough devotees.

Keen to try and taste the best loaf and now to bake the best loaf, many are taking on the challenge to make sourdough bread at home. This article will explain what you need to create your very own sourdough starter.

What is sourdough bread?

Sourdough is a chewy, airy bread made through the natural fermentation process. It is said to be the oldest variety of leavened bread (bread that rises from yeast) still existing today. Some historians claim it originates from ancient Egypt, but today you can find it being eaten across the world.

“Sourdough is a slow and ancient art, perfected long ago, before industrial food processes” – Richard Bertinet, renowned Breton baker.

Sourdough loaf

How to make sourdough bread

Unlike other bread, such as a baguette or ciabatta that uses active yeast, sourdough requires nature to take the lead. To bake a sourdough loaf, you will first need a sourdough starter (or ferment) which is made using flour and water. To make a sourdough starter, flour and water are mixed and left to ferment at room temperature. Over a few days, natural yeasts begin to form in the mixture and allow the dough to rise. Bakers can then add some of this fermented mixture to fresh flour and water when they’re ready to create a loaf of sourdough bread. 

A point to note is that you will need to ‘feed’ the dough regularly before you’re ready to use it. ‘Feeding’ your sourdough starter involves adding extra flour and water at intervals to encourage the fermentation process – more on this later.

The natural bacteria that form in the fermentation process play a big role in producing the light texture and tangy taste associated with a great sourdough. Some evidence has shown that these bacteria can play an important role in our health too. Thanks to its fermentation process, sourdough is packed with prebiotics, which aids healthy digestion. Prebiotics increase the microbiome in our guts, which according to some studies can, in turn, can boost our immunity.

It is these rumoured health benefits that have led many to pivot from the traditional white sliced loaf towards the fresher, nutrient-packed loaf instead.

Sourdough starter

How to make a sourdough starter

“Making your own ferment, letting it grow, and understanding what’s happening, is like making your own yeast. It just takes a bit of time, but when you get it – it’s so simple,” says Richard Bertinet in his BBC Maestro baking course.

To make a sourdough starter you will need a few ingredients and tools. You can use a combination of flours, like French baker Bertinet who varies between spelt, rye and wholemeal flour, or you can simply opt for strong white bread flour.


  • 150g strong white bread flour
  • 50g wholemeal spelt flour
  • 150ml warm water
  • 1tbsp honey


  • A large bowl or container
  • A wooden spoon
  • A scraper or spatula

Day 1

Combine the flours in a bowl and mix them together using a wooden spoon. Then pour in the warm water and honey. Stir together until you get a thick paste. Don’t worry about any lumps at this stage.

Use the scraper to pull the paste together, scraping it from the sides of the bowl so that it collects neatly in the centre.

Cover the bowl with a baking cloth, or muslin and store at room temperature. The cloth allows the dough to breathe, which is vital to get those natural yeasts forming. These yeasts give the dough its rise and tanginess – elevating the dough’s flavour and giving it its famous name.

Leave the dough to rest for 24 hours.

Day 2

“We always imagine it bubbling away, but it doesn’t. Things take time. However, if you looked closer with a microscope – there’s a party going on,” says Bertinet.

It is time to feed your starter.

You only need half of yesterday’s mixture when feeding the ferment. Take 200g of the sourdough starter and put it into a bowl. You can repurpose the other half into another loaf or you can freeze it for future use.

Pour 75ml of warm water over the starter and stir. The dough won’t absorb it all.

Mix 140g of strong white bread flour and 15g of wholemeal spelt flour and add to the starter and water mixture. Mix together using a wooden spoon. The ferment should be quite stiff.

When we feed the bacteria with more flour and water, it creates more air in the bread and enriches its flavour. You may not notice a huge difference in the dough today, but as Bertinet says, “remember good dough makes good bread and good dough requires time”.

Cover once again and leave to rest for 24 hours in the same warm place.

Day 3

“There are bubbles everywhere. The smell is different. You can tell there are things going on. That’s fermentation,” says Bertinet of this stage.

Your dough may look different today. Bubbles may be resting on the surface and you may be able to smell the yeasts. If you pull at the mixture with a wooden spoon, you may also see some strands forming. It’s time to feed your starter again.

Take 100g of the sourdough starter and place into a bowl.   

Add 100ml of warm water and stir a little. Then add 200g of strong white bread flour. The dough should be quite stiff now. Scrape the sides and collate the dough in the centre. Cover once more for 24 hours.

Day 4 

“Use your nose, use your instincts – smell it,” Bertinet advises of this stage, adding that you’re looking for a balance between sweetness and acidity. “It’s beautiful, like a nest inside. A nest of happiness. The smell is incredible already, sweet and delicious, I love it.”

Take 200g of your ferment and mix in 200ml of warm water as before. Add 400g of strong white flour and continue to mix. The ferment will be stiff. Mix as much as you can with your wooden spoon, but if you’re struggling use your scraper or spatula.

Move the ferment to a large container and cover again for 24 hours. Then put it in the fridge so it stays dormant.

You can use half of the sourdough starter in your first loaf and save the other half to refresh in your next loaf.

“When you feel that dough in your hands it’s amazing. This will give birth to so many of your breads. This will be the foundation of all your baking efforts,” adds Bertinet.

A fresh sourdough loaf

Beyond the loaf

If you’re looking for ways to repurpose that excess sourdough starter there are other recipes you can use it for.

Love pizza? Why not use the starter to create a pizza base? This is something many foodies and restauranteurs have caught on to in recent times. Using sourdough ferment in your pizza dough makes it lighter, slightly chewier, and just delicious.

Others have repurposed their sourdough starter into sourdough crumpets, sourdough pancakes, and even savoury sourdough hot cross buns. Or if that’s too adventurous you can simply stick to making another loaf.

It’s no wonder our taste for sourdough has stood the test of time. Its simplicity and versatility makes make it an appealing food for many. Ready to make the perfect sourdough starter? Take a look at Richard Bertinet’s course on Bread Making where you’ll learn his own personal sourdough starter recipe (with honey!) and much more.

Learn more about bread

Join renowned French baker Richard Bertinet as he shares with you the skills and techniques learned over his 40-year career. From crunchy baguettes to spongey focaccia, Richard will transform you into a bread baker, all from the comfort of your own kitchen.

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