How to make sourdough bread: a beginner’s guide

4th September 2019

It’s Sourdough September, an annual celebration of proper sourdough and the real bakers that make it. Want to know how to make sourdough bread at home? Confused about what sourdough even is? Learn the basics with home-baker, Merlin Jobst.

sourdough bread

Sourdough is the oldest form of leavened bread in the world, dating back tens of thousands of years. So while it is having something of a renaissance, it categorically is neither new nor a fad. In fact, the only relatively new thing about sourdough is the way it’s now being spoken about, because once upon a time, sourdough was simply known as “bread”.

The leavening or rising of dough was for the vast majority of human history a by-product of a process called fermentation. This process sees omnipresent natural bacterias and yeasts digesting the carbohydrates present in a batter made from flour and water, producing bubbles of carbon dioxide that makes it rise. The fermentation process also produces lactic and acetic acids, which account for the tangy, sour aroma and flavour of naturally fermented bread.

The starter

Sourdough starter day 5

Homemade sourdough starter

‘Natural fermentation’ is begun not with a packet of dried yeast but with a starter. This is a pre-fermented, highly active flour mixture cultivated and maintained by the baker. It sounds complex, but it isn’t (here’s how you make it).

When that starter, with all its yeasts and bacteria, is incorporated into a larger quantity of flour, water and salt, it becomes an airy, tangy dough that can be baked into what we now know as sourdough bread. 

The bread

Once you’ve made your dough, it needs time to achieve its rise, and develop strength to hold its shape when risen and eventually baked.

Some bakers develop dough strength by kneading on a worktop; however, it’s increasingly common for wetter doughs (which are more challenging but produce less dry bread) to be worked through a series of ‘folds’ or ‘turns’ in the bowl over the course of the rise. This can take six to 12 hours depending on innumerable environmental and ingredient factors. It can also be controlled by using a fridge to ‘retard’ the loaf.

Time: the crucial ingredient

Real sourdough loaves cooling at BreadBread bakery. Read more here on why supermarket ‘sourdough’ is a con.

Time was the main problem with sourdough bread as the industrialisation of food production took hold in the 20th century. Sourdough cannot be rushed. So fast-acting commercial yeasts quickly came to be normal practice for most available breads.

Other than the loss of flavour, texture and nutritional value, the main problem with this happening is that fundamental truth about leavened bread – that the rise is a by-product of fermentation rather than an end in and of itself – began slowly to be lost. Along with almost everything that made bread a staple in the human diet throughout our recorded history.   

Practice and familiarity

There is one final essential ingredient to sourdough: practice and familiarity. Baking with natural yeasts is not something that translates well to the modern recipe format of precise ingredients, timings and temperatures. It’s much more free than that; something unique to the environment and individual.

Following the recipe to the letter will rarely get you the results you want. In my own early days, the problem was that I was afraid both to move away from the recipe if I needed to and recognise when that might be.

While baking in this way may sound intimidating or unnecessary, for somebody who enjoys baking it’s also an incredibly exciting thing to get stuck into. It trains you away from recipes and towards trusting your own instincts. There are plenty of forums and Facebook groups to turn to for help, too.

Rather than a strict recipe, here’s how to make sourdough with a few simple steps:

First, make a starter

When it is reliably doubling in size over 4 to 8 hours, it is ready to leaven bread. Catch it sometime around its peak. When measuring starter readiness,many recipes will say to perform a ‘float test’ by dropping a spoonful of active starter into water. However, this actually is a poor metric for readiness; a starter is ready to leaven bread when it has doubled in size, and can even be used for a while before and after that point if you adapt your bake accordingly.

A less- or over-ready starter will simply necessitate a longer bulk fermentation to allow the activity to build up in the dough rather than the starter itself, and it’s up to the baker to decide when that process has concluded.

Make the dough

For a simple loaf, work with around 100g of active starter, 500g of mostly strong white flour, 375g of 27°C water and 10g fine sea salt. In a transparent container or bowl, combine all but around 25g of the water with the starter first, ideally using your fingers to encourage bacterial activity in the mixture. Incorporate the flour and combine thoroughly.

Leave for around 30 minutes to allow the flour to relax and become more workable. Then add the salt, the rest of the water, and work well until a smooth, elastic dough forms.

Leave it to ferment

Then leave, turning every now and then over around four hours to develop gluten and structure, taking care not to tear the dough. This is known as the ‘bulk fermentation’ stage.

Shape it

Once pillowy and doubled in size, shape it. Shaping is a skill, and like any skill, it improves with practice. YouTube is filled with fantastic instructional videos on shaping bread. When shaped, transfer to a dusted proving basket (rice flour mixed 1:1 with regular or rye flour is particularly good for this).

Prove again

Leave for another few hours until the loaf has noticeably risen, and either bake straight away or retard in the fridge for ideally no longer than 12 hours. While retarding does slow the fermentation down, if left for too long the gluten structure will collapse.


sourdough bread

Baking good bread in even the worst of ovens is possible, with the help of a heavy-lidded (ideally cast iron) pot or Dutch oven. This keeps in steam brilliantly, mimicking the injectors of bakery ovens, which helps the bread develop a good, brittle crust. Preheat your oven with the lidded pot inside to 250°C, and then carefully transfer your loaf to the pot.

Quickly and confidently slash the top with a serrated knife or razorblade to prevent splitting as it ‘springs’ in the oven, and bake with the lid on for 20-30 minutes.  Then for a further 25 minutes at 230°C, until the crust is dark and golden.

Leave to cool…

For at least 30 minutes and ideally 1-2 hours to allow the crumb (the body of the bread within the crust) to set. Eat and store it properly.

And that’s it.

Remember, no recipe is going to give you all the answers, so experiment. Different flours behave very differently, and changing the hydration (wetness) of your dough (and starter) will have enormous impact on the whole bake. Retarding also dramatically affects the flavour of the bread (upping the sourness in particular) due to the extended, slower fermentation.

No single measurement or step is by any means a golden rule. It may prove disastrous on your first attempt, but don’t panic – make a note of what worked, and troubleshoot any issues online. Never fear you are asking a silly question – every sourdough baker will have wondered the same thing at one point or another.

Made bread, but got leftovers that need using? Here are some stale bread hacks and tips.

Love sourdough, but don’t have time to bake? Get your loaves here at

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