Cooking Thinking

How to make your own sourdough starter

21st February 2020

Want to know how to make a sourdough starter? Worried that it’s too difficult to even try? Think again. Home-baker and sourdough fanatic, Merlin Jobst, shares a straightforward guide.

Sourdough starter day 5

There are a lot of common misconceptions about sourdough starters. One is that they are difficult to maintain and easy to ‘kill’. Another is that the best ones are generations old. And another is that they are difficult to use to make bread. But the real truth about sourdough starters is quite the opposite. In fact, their origins mean almost nothing, they’re easy to maintain and use and they’re far tougher than they’re given credit for.

Starter is a natural form of yeast used to make bread rise (or ‘leaven’ it). It can be grown by anyone, anywhere, using a simple batter of flour and water. While this mixture on its own is nothing particularly special (it tastes bland, and certainly won’t “do” anything exciting), with the addition of time and the bacteria in the air, it ferments. And this is where things start getting magical.

1. Start with the flour

Making and keeping a simple starter is easy. First, mix up a big batch of the flour you want to use; equal parts strong white bread flour and whole wheat or rye flour is a good place to begin. Rye is particularly good starter fodder for a number of reasons. Not least that bacteria love it, which means you’ll be rewarded with impressive and reliable activity. Having this flour mix at the ready will make feeding your starter easier as you build and maintain it.

Sourdough starter 1

Sourdough starter: day one.

2. Combine flour with water

Then, in a small jar or glass, combine roughly half a cup of the flour mix with the same amount of lukewarm water. Mix with either your fingers (a good way to encourage fermentation) or a spatula until a thick, lump-free batter forms.

3. Leave it alone

Leave the mixture to its own devices, covered loosely with a lid or cloth, until signs of activity start showing. This usually takes between two and three days, depending on numerous environmental factors, such as ambient temperature. Keep your eyes and nose on the prize; you’re looking for bubbles on and beneath the surface (which is why using glass is advisable), and smelling for a change in the aroma from floury and dull to a milky, sweet and fruity sourness.

sourdough starter

Sourdough starter: day four

4. Feed it

When your new starter is showing signs of activity, it’s time to house it properly. Transfer it to a bigger jar (mason jars are particularly good for this as the lid can easily be kept loose) and feed it with equal weights flour-mix and water (around 100g). Leave for a day or overnight, and then check for activity; you should see and smell a little, if not lots.

Sourdough starter day 5

Sourdough starter: day five

5. Remove and replace

While you’re still building the strength of your starter, it’s necessary to discard some between feedings to keep it at a manageable volume. Once your starter is reliably active, discarding won’t be necessary, because you can use what you take out to leaven bread or make treats such as pancakes or crackers.

But for now, remove about two-thirds of your burgeoning starter and replace with equal weights flour and water again. A good rule of thumb for the ratio of starter to flour to water for feedings is roughly 1:2:2. For example, for 50g of starter left after discarding, feed with 100g each of flour-mix and water.

Sourdough starter day 6

Sourdough starter: day six

Go on like this until your starter is rising and falling reliably (see above and below on day six), making sure to observe its patterns and smell its various stages along the way. This monitoring is an essential part of keeping and baking with a starter, because the truth is that no guide is going to be a perfect fit for your own kitchen’s environment and the goal is instinctively to know what it needs.

Sourdough starter: day six

6. Maintain your starter

Once you and your starter feel familiar with each other, the trick to maintaining it is… well, to maintain it. The key consideration will be how often you wish to bake; if the answer is ‘regularly’, then you can keep your starter at room temperature, provided you feed it at roughly 12-hour intervals, removing around two-thirds each time.

7. Store your starter

However, if you don’t plan on baking regularly but wish to keep a starter on hold for when you do, then your healthy, active starter can be kept in the fridge, where it will need only one feed per week. To feed a refrigerated starter, remove it from the fridge, feed as usual, leave for around two hours to allow it to gain some fresh activity, and return to the fridge for another week.

Or, to bake with a refrigerated sourdough starter, remove it from the fridge well in advance, and feed as above. It may take more than one feed to regain enough activity to leaven bread, but once it has reliably doubled in size over 4 to 8 hours (depending on the environment and its condition), it is ready.

Sourdough starter day 8

Sourdough starter: day eight

Can you ever kill a starter?

The above method of feeding is also a good way to revive a starter that has sat dormant for a long time, in or out of the fridge. While there is often concern about the risk of ruining or ‘killing’ a starter, especially a very old one, it really is rare that a starter has been so neglected as to be completely unrevivable. Even in the worst cases, a single tablespoon of the ailing starter can work wonders on a big feed of fresh flour.

Is a generations-old starter better than one I made from scratch?

No, not really. Your starter is, more than anything, a microcosm of the environment in which it lives and breathes. Not a library of environments past. While starters do get stronger and more reliable with age, this is down to much more than their origins. This is nothing to feel disappointed about, though; the romanticism of an ancient starter might be compelling, but it pales in comparison to being able to turn a simple dough into beautiful airy bread using a culture you’ve grown and nurtured yourself.

Next step, make your own sourdough bread. Find our easy guide here.

Love sourdough? Want a ready supply straight to your door? Check out the range on

Find out how to make sourdough bread last longer, or click here for more tips on what to do with stale bread. 

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