How to make a sourdough starter from scratch?

THE SOURDOUGH STARTER is the most important element when it comes to sourdough baking. Your sourdough starter is the one responsible for making your dough rise, but also plays a role in the final texture and flavour of your bakes.

For a more detailed step by step guide, including variations that might occur (as each starter will develop differently), I have written a complete guide on how to make your own starter and its long term maintenance.

First of all, what is a sourdough starter?

A culture of ‘wild/natural’ yeast & bacteria, replacing the commercial yeast that helps your dough rise.

The sourdough starter is made of two very basic ingredients, water and flour. During fermentation the mixture becomes colonised by wild yeast and lactic acid bacteria. Some of these are coming from the flour, some from your environment and also your hands.

Yeast is that responsible for the bubbles, the released gas. This fills the gluten network and makes not only your starter to increase in volume, but also your bread rise. The yeast is also responsible for producing alcohol. It’s the dark watery layer you get on the surface when the starter is left for too long unfed.

Bacteria are those responsible for creating lactic acid during the fermentation. This will influence the acidity profile of your starter, and the sourness of your bread. This is what ultimately gives the unique aroma and texture of the sourdough.

The characteristics of your starter will be defined by couple of things. The flour you use, the temperature in your kitchen, how often your starter is refreshed. But also things like your environment, your hands & microbiome. That’s why no two starters are the same, even if most of the variables are similar.

What if I don’t have a starter?

You can go the easy way and ask a bakery to give you some. Or ask another baker living close-by to share some, or a friend who’s into baking. Or ask me to send you some dehydrated sourdough starter (subject to your location and postage costs). Getting a starter ready to use takes off the pressure of making it work and the frustration of failures. This way you can get straight into sourdough baking.

Or you can make your own sourdough starter from scratch. You just need 2 simple ingredients, flour and water. A jar and a lot of patience.

How to make a sourdough starter from scratch?

Although at first it sounds like an easy task, it may not be as straightforward as other processes. You rely a lot on the flour you use, temperature in your kitchen and the wild yeasts and bacteria present in your home. You should not get frustrated if it doesn’t go well from the first attempt.

I have experimented with making a starter from scratch several times over the last years. Some were successful on day 3, some on day 10, some were abandoned. You may find it complicated at times, but when you nail it, you will be over the moon.

Happy to share with you the steps to follow to make your own sourdough starter from scratch. As everything to do with sourdough, there will be variations and development may vary. That’s why the sourdough starter complete guide might be more suitable to follow.

First of all you need a jar. Which is the best sourdough starter jar?

• A 400-500ml glass jar is the right size to start with. Not too big, nor too small
• Choose a jar with a wide opening, not too tall either. These features will make stirring your starter easier
• Do not worry too much about the type of lid, any kind of lid is suitable (plastic, wood, stainless steel)
• Choose a jar with straight walls, no creases or bends. This will make cleaning easier

TIME

Building a starter takes time, no one can predict or guarantee how long this will take you. Best to start it when you know you’ll be around for the next 2 weeks or so. And this doesn’t mean a 24/7 monitoring, but you should be able to check on it everyday if you want to increase the chances of success.

TEMPERATURE

The optimum temperature for making a starter from scratch and for the yeast and bacteria to thrive is in the range of 24°C – 27°C / 75°F – 80°F.

In a cold environment (< 20°C / 68°F) it might take longer for the starter to take off, it might look sluggish and not much activity going on. If that’s the case, here are a couple of tips on how to keep it warm.

• use warm water when feeding your starter. It can be up to 36°C / 97°F. If you haven’t got a thermometer, you can do the following. Pop your index finger in the water, it should feel just wet, not warm, nor cold, as 36°C / 97°F is close to our body temperature.
• try to move the starter jar in the warmest room in the house, doesn’t have to sit in the kitchen if it’s too cold
• place it close to a heat source, making sure it’s not too hot, as it can cause overheating
• keep it in the oven with the light on or just preheat the oven to 30°C / 86°F and switch if off before placing the starter in
• and finally, if your kitchen is cold all year round, you can also invest in a sourdough starter warmer like Goldie, from the Sourhouse. Goldie maintains the right temperature for your starter to thrive. And here is a 10% discount code (SE23) should you decide to buy one 🙂

WATER

Any water that you would normally consume is fine to use. It can be bottled water or filtered tap water. 

With regards to the temperature, use warm water to compensate for a cold kitchen (it can be up to 36°C / 96.8°F).  Use cold water to compensate for a hot kitchen.

FLOUR

Depending on where you live, you will have access to different flours to the ones I use. Therefore, the development of your starter can differ slightly to the one I describe below.

Best flour for sourdough starter

Opt for bread flour over all purpose flour if you can. Or, if you prefer a whole grain starter, I would choose rye flour over wholemeal. The flour you use will give the profile of your starter and ultimately to your bread. A whole grain starter will yield more sour loaves, than a white wheat one (however this is not the only factor that will influence the flavour of your loaves).

step by step instructions

Day 1.
In a jar, mix 30g water + 30g flour, stir well, place the lid loose and leave on the counter. It needs to be in a warm spot, move it in the warmest spot in your house. Do NOT overheat it though. [TIP] you could place it in the oven with the light on. Make sure you don't forget about it and bake it.

Day 2. max 24h later
What to expect: 
a few bubbles, slight rise or even no rise in volume, texture changing to a rather gluey one when stirred in. These are all normal, so give it another feed when 24h have passed.

Do NOT discard, but ADD 30g water +30g flour, stir well, place the lid loose and leave on the counter.

Day 3. max 24h later

What to expect:
more bubbles, DOUBLES IN VOLUME, very gluey when stirred in, yoghurt like notes, but also sour. These are all your signs that your starter is doing well, you can now discard. Keep 40g starter and add 40g water and 40g flour. Stir well, loose lid, on the counter.

however, if there is not much activity vs previous day, do NOT discard, but ADD 60g water and 60g flour to help build the culture.

Day 4. Max 24h later

What to expect:
very bubbly, doubles in volume, very gluey when stirred in, smelling milky, but also sour. These are all your signs that your starter is doing well, you can now discard. Keep 40g starter and add 40g water and 40g flour. Stir well, loose lid, on the counter.

however, if there is not much activity vs previous day where it doubled in volume, do NOT discard, but ADD 40g water and 40g flour to help build the culture.

If you have not discarded until now and your starter still doesn't show any increase in volume, discard nevertheless, as you start building an enormous amount of starter. And it's not only the size of it, but also the fact that with size, it tends to become more acid/sour and the chances for it to take it off decrease. Keep 40g starter and feed with 40g water and 40g flour.

Day 5. Max 24h later

What to expect:
very bubbly, doubles in volume, very gluey when stirred in, smelling milky, but also sour. These are all your signs that your starter is doing well, you can now discard. Keep 40g starter and add 40g water and 40g flour. Stir well, loose lid, on the counter.

If there is still not much activity, my advice is to try and change the flour or if you think your kitchen is too cold, move your starter to the warmest spot in the house. Keep 40g starter and add 40g water and 40g flour. However if you have discarded the day before, do not discard again, just add 40g water and 40g flour.
Stir well, loose lid, on the counter.

Repeat the above until your starter shows clear signs of activity - ideally it would double in volume for at least 3-4 consecutive feedings before you start using it. Somewhere between days 5 - 10 you can have an active starter and ready to use

To help visualise it, check this video.

INFO to be used WITH the instructions above

🌾 The ‘DAYS’ in the schedule are to be used as guidance. Based on how your starter develops you might have to bring feedings forward (feed at 12 h instead of 24 h), very unlikely to have to delay it

🌾 If the starter stops growing in volume, and instead you see it collapsing, move to the next feed even if the 24h have not passed. It can also happen that it doubles in volume in 6-8h (happy days), just go ahead and feed it.

🌾 If within 24 h from feeding your starter shows a watery layer at the top (or even in the middle or bottom of the jar). OR you notice yellow patches and a cheesy smell, move to the next feed even if the 24h have not passed.

🌾 Say you’re trying to make a white wheat starter (bread flour in the US or strong white flour in the UK) and there’s not much activity after day 4, try to mix with rye flour the next feeding (go for 50% white flour – 50% rye)

🌾 There will have to be discard, because otherwise you will be building an enormous amount of starter, as you’ll be adding water and flour at every feeding. Not only this, but the culture will be more acid, very liquid and will not rise much in volume as the yeast won’t have enough food to feed on and release the gas.

🌾 In the first days of discard, the mixture won’t have enough strength to raise a dough. If not too sour (you could tell this either by its smell) or if no strong unpleasant odour, you could use the discard for something like pancakes, crackers, etc – any recipe which is not calling for yeast.

🌾 When your starter is ready, you can make your first bread (yaaaay), and then it goes into maintenance mode. You can now move it to the fridge, and fed before using it next time. For more guidance, check the Starter Maintenance section

Most frequently asked questions

How do I know the starter is ready?

🌾Wait for your starter to double in volume for at least 3-4 consecutive feeds, before making your first bread. The fact that it has doubled once doesn’t mean it’s ready. You want to make sure it has enough strength to rise your dough and a healthy culture of wild yeasts & bacteria

🌾Another mandatory step before preparing your first dough, is to increase the feeding ratio from 1:1:1 to a 1:2:2 (30g starter +60g water + 60g flour), and if it doubles in volume in under 8h, this is your green light to go ahead and make your first dough. If it doesn't double in volume or if it’s taking 10h+ to do so, give it some more feeds before you make your first bread. Why? This is a sign that your starter is not yet strong, and if it cannot double in volume when fed in a 1:2:2 ratio, then how could it rise the dough (when even more water and flour is added)?

🌾You want your starter to show some predictability after each feed. You can be confident that it will take ‘x’ amount of time for the starter to double at a given ratio.

🌾A simple way to assess its readiness is the so-called float test.
Take a spoon of unstirred starter and drop it in a glass or bowl filled with water. It is said that if the starter floats it is ready to use, if it sinks to the bottom, it’s not there yet. In reality, the sourdough starter may not always float when dropped in water. The float test should not be the only way to judge its readiness. Consider other signs to assess your starter readiness: it’s very bubbly, it doubles in volume, it has a tangy smell and flavour and a gluey consistency.

It's ready, I make my first bread, what next?

It can go in maintenance mode. Before moving it into the fridge, I would give it another couple of feeds to strengthen it.

Should the lid be loose?

Yes. During fermentation, yeast will produce gas which has to escape somehow. If you close the lid tightly, you might experience a burst when opening it.

My kitchen is very cold - below 20°C/68°F

Yeasts love warm environments to be active. Making a starter from scratch at low temperatures can be challenging, I am not saying impossible. Try and find a warmer spot in your house to store it after feeding. Definitely use warm water (36°C / 97°F) when feeding.

How to track changes in the volume of the starter?

You might want to use a rubber band  or an erasable pen (unless your jar is graded)

My starter has developed a strong unpleasant smell. Is this normal?

Yes, the starter may develop a strong unpleasant odour in days 3-4. There’s nothing to worry about, the odour tends to disappear after a couple of feedings. This is due to an imbalance with the bacteria in the culture.

My starter is particularly liquid. Is this ok?

If your starter seems particularly liquid/runny at some point, reduce slightly the amount of water vs the amount of flour you feed it at the next feed. This will change its consistency

I am following your instructions to make a starter from scratch, but nothing happens. What's wrong?

It could be a couple of things.

No 1 is the temperature. Ideal temperature is between 23° - 27°C / 74 - 80°F. In a cold environment (21°C / 70°F or below) it might take longer to take off, looking rather sluggish or not taking off at all. Try to find a warmer place in your house, use warm water at feeding (36°C / 96°F)

The other most common cause is the flour. Flours are all so different, and when building a starter we are relying on the wild yeasts and bacteria that comes with it. It comes all the way from the grains, and further from the soil where the grains have been grown

What flour should you be using? Ideally a flour that’s rich in protein - it can be anything like bread flour, strong white flour (and its equivalent in other countries). If you can use stoneground white, wholemeal flour or rye flour, even better. Those tend to be richer in enzymes and the good stuff for the culture of wild yeast & bacteria to take off

If you have tried with bread flour and it’s not taking off, try to mix it half/half with wholemeal or rye.

The process is NOT the same for all, as development can differ from starter to starter. It's never linear, and it comes with ups and downs. 

For much more questions & answers, you might consider purchasing my Sourdough Starter Guidebook