Whether you’re new to sourdough or you’ve been keeping a starter for some time, understanding sourdough starter feeding ratios can really help you have more control of you starter, how much it yields and when it’s ready to use.
What is a sourdough starter feeding ratio?
A sourdough starter feeding ratios are referring to the amount of flour, water and starter you use when feeding or refreshing your starter.
How do you feed a sourdough starter?
Feeding a starter can be confusing at first. When I got started with sourdough I assumed feeing your starter would just be adding more flour to your starter, like feeding a gold fish.
I was wrong.
Feeding a sourdough starter is more like refreshing it. I keep a ginger bug too, and feeding a ginger bug is just adding more ginger and sugar. This is much different.
To feed a sourdough starter you take a small amount of the established starter and mix it with new flour and water.
This can be done in the same container, by removing most of the sourdough and “discarding” it. That can mean literally throwing it in the trash, or saving it for discard recipes.
Or you can remove a small amount of starter and place it in a clean jar with new flour and water. Put the old jar of starter discard in the fridge for later or use it to make discard recipes.
You may also be feeding your starter when you’re baking of course. When doing that, you will be using your starter for your baking recipe in place of store bought yeast. Always save a small amount of starter to feed and keep your starter going and growing.
How to know how much flour and water to feed to your sourdough starter?
This is where feeding ratios come in. As with most anything, there are a lot of ways to do this “right”. Some people insist of one perfect way of caring for a sourdough starter. From my years of experience experimenting I find that to be untrue.
How much flour, water and established starter go into your feeding depends on what you want from it. It’s good to start by asking yourself two questions: “Why am I feeding my starter?” and “What do I plan to do with this starter later?”.
Why feed your starter?
A starter needs food to live and thrive. To have a well established starter, you need a good solid regular feeding routine.
You will need to feed your starter if it has risen and fallen again (about every 24 hours*). Or when it has risen fully and you are baking with it (at about 12 hours).
If a starter seems sluggish, it might be a good idea to feed it every 12 hours regardless if you’re going to bake with it.
*These times listen above are general and only for context. The time it takes your starter to rise and fall depends on a ton of factors. Ambient room temperature, types of flours used, how much water used, how much starter added and more. This is where understanding sourdough starter feeding ratios comes in handy. It will allow you to have better control over how long it takes for your starter to rise and fall. More on this in detail below.
Feeding your starter to get ready to bake
When you know you want to bake a batch of something delicious later, you’ll need to first start by calculating when to feed your starter so it will be at peak when you’re ready to start your recipe. You also need to calculate how much starter you will need for the recipe you’re using and make sure you have enough plus extra to feed and continue your starter on.
For most people that would be feeding your sourdough starter 8 to 12 hours before starting your recipe. As I said above, the time it takes for your starter to rise to its peak will vary based on your environment and materials, but what if there was some way we had more control over how fast, or how slow, a sourdough starter would rise?
Sourdough starter feeding ratios
That’s right, understanding feeding ratios will allow you to have more control over how quickly your starter comes to peak and is ready to bake with.
Sourdough starter feeding ratios are, unfortunately, math. Don’t let that deter you! It’s functional math with a purpose. A delicious purpose. It’s easy enough that I can understand it, so just about anybody should be able to wrap their head around this concept too.
How to calculate how much sourdough starter I need?
First look at the recipe. My typical bread recipe using 100g of starter. That means I need to make a batch that is 100g with some extra to use for feeding a growing a new starter to replace what I’m using.
At this time I also consider if I want any sourdough starter discard to keep in the fridge for other recipes. Let’s say I don’t need discard. I can feed my starter 13g starter, 65g flour and 65g water. This will leave me with about 143g of finished starter. I can use 100g for my bread recipe and I will have 43g left over to feed to a new starter or add to my discard jar.
How to calculate a sourdough starter feeding ratios
To calculate a sourdough starter feeding ratio you need to know 3 things.
- How much flour is used?
- How much water is used?
- How much starter is used?
For this exercise I’m going to assume that you, like me, are feeding equal parts flour and water.
Let’s say a jar of starter was mixed up with 10 grams of established sourdough starter, 20 grams of flour and 20 grams of water. This makes for easy math. This would be a 1:2:2 ratio. 1 part starter to 2 parts flour and 2 parts water.
20 divided by 10 is 2. If the flour and water are the 20 and they starter is 10, then we know it takes twice the flour and water compared to the starter. Let the starter always be one part, and then math and figure out your flour and water parts.
Let’s do it again with a different ratio.
10 grams starter, 50 grams flour and 50 grams water = 1:5:5 ratio. 50 divided by 10 is 5, so we have 5 times the flour compared to the starter.
Math makes my head hurt
More words make math more confusing for me. I’m so likely to just forget that I even wanted to try if someone is starting to over explain something to me. I feel like I’m already doing that to you, reader. For that, I apologize. Instead below I will simply write out some feeding recipes in grams, and then show you their feeding ratios. You can figure it out from there.
- 25g starter
- 100g flour
- 100g water
Example 1 is a 1:4:4 ratio
- 30g starter
- 150g flour
- 150g water
Example 2 is a 1:5:5 ratio
- 100g starter
- 300g flour
- 300g water
Example 3 is a 1:3:3 ratio
Watch my full video on sourdough starter feeding ratios here
Are you getting it? Great, but why is it useful?
The reasons that knowing sourdough starter feeding ratios are useful are many. Understanding sourdough feeding ratios can allow you to adjust to amount of starter you are making and still keep the same ratio.
Example is that feeding 10g starter, 50g flour, 50g water will yield about 110g of finished starter. This is a 1:5:5 ratio. If you need more starter because you will be baking with it, but you want it to rise at the same rate you can do the recipe from example 2 above and know it is still a 1:5:5 ratio but will yield 330g of finished starter.
Oh no, am I over explaining again? Let’s move on to the really important part.
How do sourdough starter feeding ratios affect your starter?
It can affect how fast it rises! That’s right, if you want your starter at peak sooner than later, you can feed a larger percentage of starter to flour and water and have it rise faster
Why does a higher amount of starter in a ratio come to peak faster?
Because more starter means more bacteria and yeast and less food. The yeast (starter) will eat through the food source (flour and water) faster than if there was less of them. This means it will reach peak and start to fall sooner than a mix that had a ratio with less starter and more flour and water.
If I want to start a bread dough as soon as possible, I could even do a 1:1:1 ratio, say 50g starter to 50g flour and 50g water. That would yield about 150g finished starter and it would rise really fast.
If I want to feed my starter in the evening and have it at peak in the morning about 12 hours later I could feed a 1:5:5 ratio. 13g starter, 68g flour and 68g water will yield 149g finished starter and is still about a 1:5:5 ratio. Less yeast and more food to eat means they will be busy snacking longer and it will take longer for it to reach peak and begin to fall.
Sourdough starter feeding ratios and the Health of your Starter
While a 1:1:1 ratio can work to achieve a peak starter quicker, it might not be the best way to feed your starter all the time. If you’re constantly feeding a low amount of starter to flour and water, your starter may eventually become stressed.
I like to vary the feeding ratio based on what I’m using it for. If I’m just feeding for maintenance and not for a baking project that needs to be ready at a certain time I usually feed 1:5:5. Plenty of food and I won’t have to feed it again for a while.
Watch My Ten Steps for Making Sourdough
Let’s look at sourdough stater feeding ratios another way
Let’s pretend your starter, your captive colony of bacteria and yeast, are a party of hungry teenagers. For this example, I will pretend hamburgers are the flour and water.
If you have a group of 30 hungry teenagers and you bring them 30 hamburgers you are giving them enough food for all of them to fill their bellies for a meal, but they are going to be hungry again at their next meal in a couple of hours. This is a 1:1:1 feeding ratio.
If instead you were to bring that same group of 30 hungry teenagers 60 hamburgers that could be enough food to hold hunger out longer and keep them happy through 2 meals. That is a 1:2:2 ratio.
If you’re crazy and bring them 90 hamburgers that same group of 30 teenagers you might be able to leave them be for a whole day before they get cranky. That’s 3 burgers for each kid. A 1:3:3 ratio.
See how that works? The more food you have available as compared to the amount of teenagers (yeast) the longer they will be fed and the longer it will take for them to eat all the food.
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That’s more than enough for today friends.
Boy oh boy, talking about math is exhausting. It all makes more sense when you start using it and stop studying it, don’t you think?
Do you use sourdough starter feeding ratios as a guide? Would you explain it differently? Let me know in the comments.
Next time we’ll talk baker’s math. Kidding! Well, maybe.