The thing that makes sourdough bread different from any other type of bread is the starter that is used to make the bread grow. But to make the best possible bread you can’t simply mix the starter with the rest of the dough at any time, there is a specific time frame when the starter is at its peak, and it will make the best bread possible.
On average a sourdough starter will reach its peak between 4 and 12 hours after feeding. A sourdough that has reached its peak will have a lot of bubbles on its surface and has reached its maximum rise point, after which it will start deflating.
Between 4 and 12 hours is quite a big timeframe, so you can’t really use time as an indication that your sourdough has reached its peak, so it’s usually better to look at other signs. After we discuss those signs I will also share with you a quick and simple test that will tell you if your starter is ready, which can be done in under one minute.
How to Tell That Your Sourdough Starter Has Reached Its Peak
Every starter out there is different, even if it follows the exact same recipe and feeding schedule. And this is mostly due to the fact that not every pack of flour is the same, even if it’s made by the same company, and due to the different exterior factors like humidity and temperature.
If you want to know more about those factors and all the different ways that they influence the sourdough check out my article: Is my Sourdough Starter the Right Consistency? (Beginner Guide)
Now let’s go over the signs that you have to look out for to know that your sourdough starter is at its peak. And we’ll start with the simplest one: bubbles.
Bubbles on the Surface of the Sourdough Starter
Bubbles are a very good sign in a starter, it means that there is a lot of activity going on in the starter, and that is exactly what you want. A starter that has no bubbles at all is a really bad sign, and it means that your starter is far from being ready to be used.
A starter that it’s at its peak will have a surface full of different-sized bubbles. And it’s a sign that this is the best moment to use your starter.
Bubbles are created when the bacteria living in the starter are feeding the starches and sugars found in flour. After they eat them, they will release a gas called carbon dioxide, which creates the bubbles that we are looking for.
When you add new water and flour to the starter you are feeding the bacteria, as well as giving the chance for new ones to appear. The starter will reach its peak point when the bacterias are at the highest number and are eating as much as possible, thus releasing the most carbon dioxide, which also makes the starter rise. And this brings us to the next sign.
The Rise of the Starter
So, as the bacteria eat the starches and proteins they form carbon dioxide bubbles, and as those bubbles form the starter rises. And while all this happens the bacteria multiply.
All of those things will happen up until the food starts to run out, at which point the number of bacteria will also slowly start to decrease. This is the moment that we are looking for.
When the starter starts deflating the bacteria inside it are very hungry and looking for food, this is when the starter is at its peak, and it’s the moment to combine it with the rest of the dough to work its magic.
One thing to keep in mind is that different types of flour have different rising points. For example, hard white wheat flour will double in size, while whole grain flour won’t rise as much. So just because your starter hasn’t risen as much as other starters that you’ve seen doesn’t necessarily mean that your starter is not good.
Marks on the Glass
When I started making sourdough I used to make small marks on the glass to see how high it would go. This helped me a lot when I wanted to use it at its peak because I already had an idea of how much it would grow.
So take a marker and start making marks on the jar, while this won’t help you out immediately it will definitely help you in the future.
Timing the Rise
As I said, using time as the only measurement is not a good option, but it can be really helpful if you combine it with the other methods.
Again, this will not help you right now, but over time you will get an idea of how much time your starter needs to reach its peak.
Just make sure to pay attention to the temperature of the room, a cold room will make the starter slide slower, and a hot room will make it rise very fast. So take this into consideration when timing your dough.
The Glass of Water Test
If you are not exactly sure if your starter has enough bubbles, or if it’s still rising or has stopped, there is one simple test that you can do to see if it’s ready to be used, and all you need is a glass full of water.
Here is how to do the test, step by step:
- Fill a glass with water, the water should be at room temperature, otherwise, it might interfere with the results, and the glass should be transparent, so you can see the state of the starter better.
- Give your starter a good mix, you are doing this in order to evenly distribute the bubbles. If the bubbles are not distributed equally it could make the starter act weird during the test.
- Take a spoon and scoop up some starter and place it on the surface of the water, you want to do this as gently as possible.
- If your sourdough is floating then you are ready to make some bread, congratulations!
- If the sourdough has sunk you have to wait a little longer, this happened because there weren’t enough bubbles in the starter, so you should let it rise some more.
How to Make Your Sourdough Starter More Active
If your starter won’t rise any further, there are little to no bubbles in it, and it won’t pass the glass test, then you might want to adjust the feeding schedule of your starter.
A starter that is not very active is a very common problem, but luckily there is a very simple solution, changing the feeding schedule.
If a starter doesn’t have enough to eat, in this case, flour and water, the bacteria living in it will slowly start to disappear. So there will be fewer bubbles, and it won’t rise as much as it should.
The solution is simple, feed it more often. If you were feeding your starter once per day, increase it to two times per day.
If feeding it two times per day still hasn’t solved your problem but it helped a little, there are two things that you can do. You can either feed it three times a day, or you can move to a slightly colder place.
I know that not everybody has the time to feed their starter three times a day so what you can do instead is to move it to a slightly coder place. Usually, sourdough starters become very hungry when they are kept in warm places. This can be a good thing as well as a bad thing.
It can be a good thing if you want to make bread in a few days, but if you are not planning on baking too soon, it can become a hassle. So instead of keeping your starter in the kitchen where it’s warm, move it in the pantry where it’s not as warm, or in the garage. Just don’t put it in the refrigerator, it’s way too cold in there for the starter. As an idea, the average temperature of a sourdough starter should be kept between 68°F and 75°F (20°C and 24°C).
Should a Sourdough Starter Be Used at Its Peak
The point of this article is to tell you how to know when a sourdough starter is at its peak so you can use it to make bread. But do you really have to use the starter when it’s at its peak? What will happen if you don’t use it when it’s at its peak?
So let’s see what happens when sourdough is used during the peak, after, and before it.
What Happens When You Use the Sourdough Starter at Its Peak
When a starter reaches its peak, it will stay there for around 30 minutes, so there is enough time to use it.
A starter that is at its peak will be full of carbon dioxide, and the bacteria living in it will be full of energy and hungry. And they will be at their highest population.
This means that the bread will rise to its full size, the taste will be more intense and balanced.
So, using a starter at its peak will provide the best bread, but let’s see what happens in the other two possibilities.
What Happens When You Use the Sourdough Starter Before It Peaks
While a sourdough starter that hasn’t reached its peak will still make the bread grow, it will need more time to do so, but it will still get there.
The big difference when using a starter that hasn’t reached its peak is in the taste, the bread will be much sweeter.
This is because the bacteria in the starter didn’t have enough time to eat the sugar in the flour and convert it into carbon dioxide, which gives the bread its taste and name.
What Happens When You Use the Sourdough Starter After the Peak
A sourdough starter that has gone past its peak will have fewer active bacteria because they no longer have what to eat, so it will take them some time to become active when combining the sourdough with the bread dough, but the sugar in the starter is completely gone and this will reflect in its taste.
Out of the three possibilities, a starter that is used after it reaches its peak will have the least leavening power, so it will take the most time to make the bread rise, but it can still do it.
The big difference, in this case, is that the bread will have a much sour taste. This is because the starter had a lot of time to develop its flavor.
Final Thoughts
The difference between using a sourdough that it’s at its peak, one that is past it, and one that hasn’t reached it is not insignificant, but I would say that it’s not that important. What ‘s really important is that when using it the starter is still active.
Without an active starter, you can’t make sourdough bread. How you want the bread to taste in the end is up to you, since everybody lakes their sourdough bread a certain way.
To make sure that your sourdough is active look for bubbles on its surface, lots of bubbles means a lot of activity.
From my experience, the best way to test if your starter can be used to make bread is the glass of water test.
If you want to use the starter at its peak the way to look out after is the level to which it rises. The first few times it might be hard to know exactly when it reached its peak, but after you do this 2 or 3 times you will instinctively start knowing.
If this is your first time trying to use the starter at its peak, don’t be disappointed if you don’t get it completely right, nobody does it on their first try. But try to carefully watch your dough as it rises, see how many bubbles it makes, how long it took it to reach its peak, and make sure to make some marking on the jar in which you keep it. While it won’t always rise to that exact height, it will usually be pretty close.