How to Know When your Sourdough Starter is Ready (8 signs)
One of the most critical part of successful sourdough baking is learning how to know when your sourdough starter is ready to use.
A strong, active starter will give you the best bread if you know what to look for!
In this detailed guide, I will answer your biggest questions: what an active starter is, why it matters, 8 signs to look for, the different stages, how to make your starter thrive, 8 tips to care for your starter, and so much more.
What’s in a sourdough starter?
Aside from the ingredients you can see—the flour and the water—the starter contains wild yeast, lactic acid bacteria, and acetic acid bacteria.
Lactic acid and acetic acid bacteria are essentially good bacteria or probiotics. There are several strains of these in a healthy starter.
There is typically only one type of wild yeast in the starter. The wild or natural yeast act as the leavening agent in your sourdough starter.
The job of the wild yeast is to rise the dough by converting starches or sugars into carbon dioxide gas while the good bacteria break down the protein structure of the gluten.
Learn more in this post:
The Cycle of Refreshing
Sourdough bakers care for their starters through regular refreshing.
Refreshing involves the feeding process which you may be familiar with, but it also includes discarding or using the starter.
If the starter is fed and fed without using or discarding, the starter will become unhealthy.
The proportion of starter compared to the water and flour it is fed must be small.
My preferred way to refresh a starter is to take a tablespoon of my sourdough starter, place it in a glass jar and feed it with 60 g water and 60 g flour for one recipe then let it rise until it is active.
Learn more about refreshing sourdough starters in this post:
Starter Feeding Ratios
As I mentioned above, the proportion or ratio of the sourdough starter to the water and flour is very important.
This determines how healthy the starter will be in the longrun as well as how quickly the starter rises in that particular cycle.
In my preferred refreshing ratio of 1 tablespoon or 20 g starter to 60 g water and 60 g flour, which means that there is only about 10-15% of the sourdough starter in the mixture.
Starting with a small amount of starter with all that food makes those little microorganisms—the wild yeast and the good bacteria—thrive because they have an abundance of food.
What is Active?
When a sourdough bread recipe calls for an “active starter”, it is referring to a starter at a certain stage of development.
This stage is after the refreshing or feeding stage and before it becomes discard.
The “food” given to the sourdough starter in the feeding step takes several hours for the microorganisms to consume to develop a bubbly, ready to use starter. (Feeding activates the starter just like warm water and sugar activate commercial yeast.)
Once it reaches this active stage, the yeast population is strong and thriving to rise your sourdough bread dough.
*Note: other recipes or articles may use the terms mature starter, ripe starter or others to refer to this ready to use stage of the sourdough starter
Why does the Active stage of Sourdough Starter Matter?
The active stage of the sourdough starter is when the yeast are at the peak of their activity which means that they have better rising power.
The chemistry of the starter is also at its healthiest with the yeast and bacteria being in a good balance of each other.
This optimal stage ensures that you will get a good rise when you bake bread every time.
For more help judging when your dough is done at other stages of the sourdough bread baking process, see these posts:
- How to tell when sourdough is done with bulk fermentation
- When is sourdough finished proofing? The signs and a test
Rubber Band and Float Tests are not enough
When starting sourdough, it is helpful to place a rubber band around the jar of starter after it has been fed level with the water and flour mixture.
That starting mark allow you to clearly see when your starter has doubled in volume as it rises up the sides of the jar.
The float test is also very popular for new sourdough bakers, when a baker tests the readiness of the starter by dropping a spoonful in a bowl or cup of water to see if it floats.
The gas that builds up during fermentation is what makes the starter expand and even become buoyant.
However, those indicators are not always foolproof. You can get false positives or false negatives from those tests alone.
Doming sourdough starter
As the fermentation process occurs, microorganisms produce carbon dioxide gas.
This gas causes the starter to rise and increase in volume, forming a dome-like shape until it reaches its peak.
Many people get excited about the volume increase and may see it double, but the starter may still be rising or doming.
While a doming starter will pass the float test, it needs to reach the ideal activity level for the best results in your bread recipe.
How to Know When Your Sourdough Starter is Ready
Depending on what ratios you used to feed your starter and the ambient temperature and other varying factors, you need something more than the clock to tell you when your starter is done.
Time is only one part of activating a sourdough starter.
The weather, feeding ratio, and other factors can slow down or speed up how quickly your starter is ready.
Below are 8 signs to look for to know when your sourdough starter is ready.
8 Signs your Starter is Ready to Use
There are a few key signs you’ll want to look for to know when your starter is active and ready to use:
- Time: The time elapsed for a white starter should be 6 to 12 hours (potentially 14 in cold temperatures).
- Volume: The starter is at least doubled in volume.
- Lots of bubbles: An active, ready to use starter should have large bubbles with lots of gas trapped in them.
- Appearance: The starter should have a shiny appearance with lots of big bubbles.
- Smell: The starter should have a pleasant smell like ripe fruit with a yeast smell or slightly tangy smell.
- Relaxed—not doming: At its peak, the starter should not have a doming appearance on the top. In fact, it should be receded down from its highest volume a milimeter or so.
- Valleys: At the peak, there should also be a dip in the top of the starter surface like a valley forming.
- Float Test: A tablespoon of starter floats in a cup or bowl of water.
Free Sourdough Guide
You can get my free Quick Start Sourdough Guide to begin learning some of the key parts of the cycle of sourdough starter.
Learn the phases, the signs of an active, how to care for a sourdough starter to keep it alive and thriving, as well as how to make your own sourdough starter.
What are the other stages of sourdough starter?
The life cycle of a sourdough starter has different stages.
The first stage of sourdough starter once its been fed is called just refreshed or just fed.
After feeding, it will rise and transition to the next stage that we are discussing in this post: active.
Once it reaches its peak of activity when it is ready for use in a bread recipe, it will begin to fall and transition to the final stage.
The final stage is referred to as discard or spent starter.
At this final stage, the starter just needs to be refreshed in order to restart the cycle.
Sourdough starter at different stages impacts dough fermentation and how it can be measured if using cup measurements as well: How much does a cup of sourdough starter weigh? (Active vs. Discard)
What is sourdough discard? What do I do with it?
Sourdough discard is the stage that happens hours after a starter reaches its peak of activity.
It is when all the microorganisms in the starter—the yeast and friendly bacteria—have consumed and broken down all the flour.
Once they have gone through the food, the population of the microorganisms has grown exponentially leaving dead and hungry microorganisms behind.
Also, the yeast and bacteria have broken down the gluten proteins in the flour to the point that it’s a liquid-like state that can no longer hold in the carbon dioxide bubbles.
What do I do with sourdough discard?
A small portion of sourdough starter discard can be separated into a new container and fed in order to refresh the starter back to health.
Or it can be saved and used in sourdough discard recipes.
Learn more about sourdough discard in these posts:
- What is Sourdough Discard?
- How do you use sourdough discard? (7 uses and video)
- Why use Sourdough Discard?
How do I get my sourdough starter to become active again?
After your sourdough starter has gone through its cycle and is discard, it is time to begin the cycle over again.
Take about a tablespoon amount of the sourdough discard and put it into a new glass jar or other container.
Then feed it with equal parts by weight of water and flour. For a basic refresh, I use 60 grams water and 60 grams flour to feed a tablespoon of sourdough.
Learn more about refreshing starters in this post:
How to care for your sourdough starter
Establish a routine that works for your lifestyle and feeding schedule to care for your sourdough starter.
You should plan to refresh it at least once each week, even if you aren’t baking that week.
Refreshing is when the bulk of the starter has been used in a recipe or discarded (literally tossed or saved separately in the fridge) and the remaining portion (about 10% of the previous batch) has been fed with equal parts (by weight) fresh flour and water.
After feeding the starter, leave it loosely covered at room temperature.
Once active, if the starter is not going to be used, place it in the fridge.
The fridge is where you’ll need to store your starter to place it on hold
Placing sourdough starter on hold or traveling
When you are going on a trip or have a week or two when you can’t bake, you’ll want to put your starter on hold.
To put your starter on hold follow the following recommendations:
- Starter should be in its active phase or discard. Put a lid on the container.
- Place your starter in the coldest part of your fridge. (Usually this is the top shelf in the back.)
- Once you return, give your starter extra care with 2-3 consecutive refreshings 12-18 hours apart until it is back to its normal activity level.
See these posts for how to revive an extremely neglected starter or how to travel with your starter:
Why cold temperatures help with starter maintenance
The cold temperatures will slow down all the activity so that the starter doesn’t become susceptible to bad bacteria growth or death by neglect.
When there is too much starter waste and the starter is in desperate need of refreshing, this creates an environment where the microorganisms can’t defend themselves from bad bacteria.
By closing the lid of the sourdough starter and placing it in the fridge, it is less vulnerable and will even create a top layer of alcohol (referred to as “hooch”) to protect itself.
Low Maintenance Weekly Care
If you plan to only bake once each week, here is a low maintenance weekly care schedule:
- Day 1 AM: Take starter out of fridge, refresh (place a tablespoon of old starter in a new container and feed) in the morning. Leave the starter at room temperature.
- Day 1 PM: Refresh starter a second time for optimal activity. Leave the starter at room temperature.
- Day 2 AM: Make dough using the active starter. Feed the remainder of sourdough starter left in container. Leave the starter at room temperature.
- Day 2 PM or Day 3 AM: Place starter into fridge to be on hold hibernating until Day 1 of next week.
- Day 3-7: Do nothing.
This is just an example of a weekly schedule. You can use this template and adjust it according to your needs.
The best way to make sure your starter performs well for your weekly loaf of bread is to refresh it twice after it has been in the fridge. You could do it only once, but twice will make sure you have the most vigorous starter!
The best time for my schedule to refresh my starter is typically at night before I go to bed so it’s active the next morning through midday. But the best time for you might be different.
Learn more in this post:
8 Tips to Maintain a Healthy Sourdough Starter
- Refresh: Don’t just feed an old starter. You must remove the bulk of the old starter by moving a tablespoon portion to a new container or dumping 90% of it out (into trash or discard storage container), then feeding the small portion with fresh water and flour.
- Regular care: A sourdough needs to be refreshed daily if left at room temperature or weekly if stored in the fridge.
- Be consistent: The more consistently you use your sourdough starter, the stronger its activity will be.
- Protect it: Cover your starter (loosely at room temperature or tightly when in the fridge) to protect it from bad bacteria or bugs.
- Warm place: Find a warm spot on your kitchen counter for your starter to sit when its becoming active.
- Adjust seasonally: Your sourdough starter will rise faster in warmer temperatures. In cooler temperatures, it will take longer to rise.
- Fridge storage: If you aren’t going to use your starter every day, use your fridge to store it when not in use.
- Revitalize with whole wheat: If your starter is being used regularly but still seems sluggish, add a small amount (about a teaspoon) of whole wheat flour with the white flour the next time you refresh.
What about a new sourdough starter?
Knowing when a brand new sourdough starter you are making from scratch is ready is a different topic.
When making your own sourdough starter, it takes time for it to develop into a mature sourdough starter.
A new starter, once established can be judged for use in recipes using the guidelines above.
A brand new sourdough starter needs to develop a consistent rhythm of rising and falling before it can be used in a recipe.
Depending on flour type and method, this takes 7-10 days. When using rye flour, it will develop very quickly in 5-7 days.
A new sourdough starter can be used once it reaches its peak within 12 hours.
Learn more about creating your own sourdough starter from scratch with this free guide: How to Make a Sourdough Starter from Scratch
What type of flour to use for feeding sourdough starter?
While I recommend rye flour as my first choice for starting a sourdough starter from scratch, I always transition it to a standard white flour starter.
A white flour starter that is fed with all purpose flour is what I recommend to all sourdough bakers.
All purpose flour gives consistent results, has less variables, is easy to find in the grocery store, is more forgiving, and inexpensive.
Why all purpose flour is the most popular for sourdough starters
I mentioned above the reasons why most sourdough bakers use all purpose flour.
During the milling process, the outside of the wheat (the bran) is stripped away leaving only the white starchy part of the flour.
The bran has lots of fiber and health benefits, but it impedes gluten development and has different microorganisms on the surface which can impact fermentation.
All purpose flour has less diversity which means that no matter where you find your flour, whether you’re in California or New York, all purpose flour will give you consistent results.
Can I use whole wheat flour in my starter?
You can use whole wheat flour or rye flour in a sourdough starter, however, I highly recommend maintaining one with white flour and having a separate one with the whole wheat flour.
Whole grain flours absorb more water so the ratio of water needs to be higher to make sure the starter doesn’t become dry.
Whole wheat flour starters and rye flour starters ferment faster than white flour starters, but the active window is shorter as well.
Some people like these types of starters for more sour flavor, health reasons, or personal preferences.
Learn more about whole wheat flour in this article:
What is a Stiff Starter?
A stiff starter made with sourdough has a higher amount of flour than water which changes the texture, timing, and flavor for the starter but also for sourdough bread.
I did a side by side experiment using stiff starter and a standard 100% hydration starter (the kind focused on in this article).
Learn more about stiff starters and see the results in this post and video:
Favorite Sourdough Bread Recipes
- How to make Sourdough Bread step by step
- Sourdough Honey Oat Whole Wheat Sandwich Bread Recipe
- Sourdough Cinnamon Twist Wreath Bread
- Sourdough Pan Dulce Conchas (Sweet Shell Bread)
- Savory Sourdough Cheese Herb Babka Bread Recipe
- Whole Wheat Sourdough Hokkaido Milk Bread, Japanese inspired
Love for Sourdough
I would love to see photos of you baking with your sourdough! You can tag me on social media @livingbreadbaker
Share this post with your baking friends so they can know the signs of an active sourdough starter too!
Comment on this post if you have any other questions or need clarification.
Just getting started with sourdough?
A competent guide transforms sourdough baking from overwhelming to uncomplicated and fun!
Get My Free Quick Start Sourdough Guide: Learn the key terms and concepts in sourdough baking, including the differences between active sourdough starter and sourdough discard, and how to care for your starter.
Time Planning Help for Sourdough Baking
The #1 need for sourdough bakers is help with time planning, so I created a resource for you.
Sourdough Time Planning Workbook: Perfect for new or experienced bakers, this workbook includes 8 templates ready to fill in and a baking journal. The templates cover 4 different ways to make classic sourdough country breads, 3 time planning worksheets for enriched sourdough bread depending on serving time target, and a blank template. The baking journal goes over baker’s percentages and how to take notes on your sourdough bakes.
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Get a free sample of the workbook: Use this sourdough time planning worksheet sample to simplify your baking.
Living Bread Baker posts mentioned
How to tell when sourdough is done with bulk fermentation
When is sourdough finished proofing? The signs and a test
How to Schedule Sourdough Baking in Your Busy Life (Samples)
How do you use sourdough discard? (7 uses and video)
Stiff Sourdough Starter vs Liquid 100% Hydration
What does a 100% Hydration Sourdough Starter mean?
How to make Sourdough Bread step by step
Honey Oat Whole Wheat Sandwich Bread Recipe
Sourdough Pan Dulce Conchas (Sweet Shell Bread)
Savory Sourdough Cheese Herb Babka Bread Recipe
Whole Wheat Sourdough Hokkaido Milk Bread, Japanese inspired
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