How to make sourdough starter from scratch (beginner guide)

Learn how to make your own sourdough starter from scratch with this simple and effective recipe. You don’t need to buy a sourdough starter to make delicious sourdough bread at home. This two-ingredient sourdough starter recipe will have you baking beautiful artisan style loaves in no time. No complex ratios, hydration levels or baker’s jargon here, this really is the easiest way!

What is a sourdough starter?

A sourdough starter, or levain, is a complex, living culture of microbes used to leaven breads and other baked goods. It contains good bacteria (Lactobacilli) and wild, natural yeast.

Sourdough starter is made from two ingredients, flour and water, which contain living organisms that ferment this mixture, creating air bubbles. Like many ferments, starters have been around for thousands of years and have been used by cultures all over the world for rising bread products. The culture, thanks to the fermentation process, creates a distinct sour flavour and light, chewy texture in baked goods.

Homemade sourdough starter, once developed can last indefinitely provided that it’s cared for properly.

How does a sourdough starter work?

The active sourdough starter, when added to flour, water and salt, cultures the dough mixture with the living microbes. When left to ferment, yeast and bacteria work together to break down the sugars and gluten protein to produce carbon dioxide (air bubbles) and lactic acid (tangy flavour).

This can create delicious artisan style bread that is full of bioavailable nutrients and is arguably easier to digest that it’s commercial yeast counterparts.

For best results, it is important to create an active bubbly starter before attempting to make your first loaf, continue reading to find out how with my step-by-step instructions!

What is the difference between sourdough starter v commercial yeast?

Commercial, baker’s, or store-bought yeast offers a similar property to sourdough starter in that it causes bread products to rise, however there are a few key differences between the two.

• Commercial yeast turns the sugar in the flour into alcohol and carbonated gas, whereas sourdough starter, with it’s lactic acid bacteria, turns the sugar into lactic (and acetic) acid and carbonated gas. This gives the bread it’s sour flavour.
• Because sourdough bread ferments for longer, the gluten in the flour starts to break down, meaning that the gluten content in sourdough bread can be substantially lower than the gluten content in commercial yeast bread. This may be helpful for people who have gluten intolerances.
• Commercial yeast is a specific strain of baker’s yeast, and is manufactured in a lab under specific conditions to make it rise bread quickly and easily. It is a single species that gives reliable and fast results. 
• Sourdough starter is a living organism containing wild yeast and beneficial bacteria species that naturally occur in the air, in the flour, and even on your hands and equipment. Because you harness the power of wild yeast and bacteria, you automatically gain a whole lot more diversity.
• One of the biggest differences is the time taken to leaven (rise) your bread, sourdough starter takes much longer and can be more unpredictable, especially in the beginning.

What should you feed sourdough starter?

A sourdough starter simply needs flour, water, oxygen and an optimal temperature to thrive. Beneficial microbes are introduced into the mixture from the flour, air, as well as from the jar, your hands and even the spoon you use to stir it. These microbes are fermentation powerhouses.

Sourdough starter can be fed several types of organic flours including all purpose flour, baker’s flour, whole wheat flour, spelt flour, rye flour and even einkorn flour. The type of flour you choose will determine the activity and strength of your starter, and there is one stand out in this group – rye flour!

Sourdough starter absolutely loves rye flour. Rye flour is naturally rich in amylases, nutrients and microbes, which creates a happy, active starter that ferments more efficiently than other types of flours. For this reason, I suggest feeding exclusively with rye flour, especially in the beginning when you are making your starter for the first time.

Once you have a nice active sourdough starter made from rye flour, you can switch to another type of flour which I have done. You will notice a big difference in colour, as you can see in the different images in this post.

Sourdough starter versus sourdough ‘discard’

You probably hear the words sourdough starter and sourdough discard being used a lot if you are new to the sourdough world. Essentially, sourdough starter is the fed, active starter that is ready to be used in baking, while the ‘discard’ is what is typically removed from the fed starter, after it has risen, and discarded before the next feeding (if you are not ready to bake bread).

When making your sourdough starter from scratch, you will need to discard some starter in the beginning. However, you will not need to continue to discard when you follow my tips on how to care for a no-discard sourdough starter. This will save money and reduce food-waste.

What are some common issues with sourdough starter?

• Slow/sluggish starter – your mature sourdough starter should at least double in size 4-8 hours after feeding. If it is taking longer to double, your starter is a little slow. This could be due to cooler temperatures or infrequent feedings in the beginning. Try keeping your starter in a warmer place, feeding it rye flour, and even try feeding it twice a day if possible.
• Bad smell – smell your starter often to get to know what it should smell like. A healthy starter should smell pleasant, yeasty, sour and a little fruity. If you starter smells off, rotten or repulsive, this is a good sign that your starter has gone bad and you will need to throw it away and start again.
• Acetone smell – sometimes when your starter has used up all the food/flour, it will develop an acetone smell and produce a clear liquid. This liquid is called ‘hooch’ and is quite common. There is nothing wrong with your starter, it just needs to be fed more often. If you feel you are feeding too often for the amount of bread you are baking, you can keep your sourdough starter in the fridge like I do. Read my tips on how to care for a no-discard sourdough starter.
• Mould – your sourdough starter should never be mouldy. If you see white, black or or coloured mould, you will need to throw it away and start again. To prevent mould, ensure you cover your starter loosly with a lid or with paper towel, and use clean utensils when feeding.
• Starter rises then falls – this is perfectly normal. When the sourdough starter has used up all the food from the feeding, reached it’s peak fermentation and produced all the air bubbles that it possibly can, the starter will start to fall/sink in the jar. This just means you have a very active starter and it may need feeding again before using it to bake bread.

How to give your sourdough starter a boost

If you have a sluggish sourdough starter, try these simple tips to give it a boost!

Feed with rye flour – as I mentioned before, sourdough starter loves rye flour. If your starter is sluggish, try feeding exclusively with rye flour.

Keep your sourdough starter in a warm place – the optimal temperature for a sourdough starter to rise is 24-28^oC. Try popping it in a warmer room, near the stove or wood fire, or in a sunny window. Be careful not to let it get too hot either!

Feed with luke-warm water – if it’s colder in your house or your keep your sourdough starter in the fridge like I do, I recommend using luke-warm water to feed your starter. This helps lift the temperature slightly and give the yeast and bacteria a little wake-up call.

Feed more often – A slow starter usually benefits from more frequent feedings, especially in the beginning. This introduces more food as well as beneficial yeast and bacteria into the starter.

A note on store-bought sourdough starters

A lot of people feel overwhelmed by the thought of making their own sourdough starter, and may find it easier to buy a starter. Store-bought sourdough starters often come as dehydrated powers that you simply add water to and continue to feed the same way you would any other starter. This may seem convenient and a quick way to start, but hear me out…

• You may only be getting a teeny tiny head start – you see, everything you need to create a sourdough starter already exists in your flour and your home. Starting with a dehydrated starter is not that much different than starting from scratch with plain rye flour.
• Beware of expensive ‘ancient 250-year-old sourdough starters’ and the like – this sounds impressive, I agree, but once you feed this starter a few times in your own home, the starter takes on the new microbes in your flour and home and loses much of it’s impressive microbial lineage. You just really don’t need to do this if you want to save some dollars. 

How to make sourdough starter from scratch

Gather your equipment and materials

You will simply need some rye flour, filtered water (or de-chlorinated), a clean glass jar (500ml) and a spoon (That’s really all!). Filtered, or at least de-chlorinated water is essential, as the chlorine in tap water will kill your beneficial microbes. To dechlorinate your tap water, simply boil some water and let it cool to room temperature.

Day 1

Using a kitchen scale, add 50 g water (filtered or dechlorinated) and 50 g flour (rye flour if possible). You can use any quantity here, as long as you use equal amounts of flour and water. I recommend at least 50g of each to start with. Stir well, you should get the consistency of thick pancake batter.

Cover loosely with lid or with paper towel and rubber band and set at room temperature, or in a warmish spot (24-30^oC).

Day 2

After 24 hours, remove half of the mixture and discard/compost. Add another 50 g rye flour and 50 g water (filtered or dechlorinated) to the remaining starter, give it a good stir and cover, return to the same warm spot.

Day 3,4 & 5

Repeat day-2 instructions every 24 hours. By day 2 or 3, your sourdough starter should start to produce bubbles and rise inside the glass jar as shown below.

Day 6 & 7

By now your starter should be forming lots of bubbles, be nice and active, and be rising up in the jar and starting to fall before the next feeding. For the next two days, repeat day-2 instructions every 12ish hours.

Day 8

If your starter is forming nice big bubbles, is doubling every 8-12 hours and smells pleasant, sour and yeasty, your starter is ready to begin making sourdough bread and other delicious sourdough goods! A great one to start with is my simple, no knead artisan sourdough bread recipe.

If your sourdough starter hasn’t quite doubled within 12 hours, keep feeding it every 12 hours until your get that nice, active bubbly starter.

How do you know when a starter is ready to use?

It’s important to wait until your starter is ready to use before attempting to make your first loaf of bread. A good trick is to place a rubber band around the jar at the level of the sourdough starter before it rises. This will make it clear to see when your starter has doubled.

Another way to check whether your starter is ready to use, is to do a ‘float test’, which simply means to drop a spoonful of your active starter into a glass of room temperature water. If the starter floats, its ready to use!