If you’re here, you’ve likely heard about the sourdough float test. In this post, we will go over what the float test is, how to use it, and what to keep in mind when considering the results.
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I’ve been baking sourdough for years now. I love the process and I love the delicious breads and various bakes, but I also love the knowledge I’ve gained through all my trial and error.
It feels good to not be completely new to this craft anymore, because the beginning, while fun and new, sure has lots of questions and second-guessing.
Speaking of questions, if you’re wondering how to get into this world of all things sourdough, check out my post on how tomake a sourdough starter.
While I’m not saying I never have questions anymore, years of experience sure make things easier to diagnose.
So on that note, there are many times when I’ve needed to know if my starter is ready for baking. With my starter being the means behind getting my bakes to rise, I need it to be at its peak.
That’s where the float test comes into play.
If you don’t know what it is, a float test might seem like an odd term when we’re talking about baking.
So, what is it?
Sourdough Float Test
This is a method for measuring the readiness of your sourdough starter in order to achieve a healthy rise. While it’s certainly not foolproof, it can be helpful.
By dropping a spoonful of your starter into a glass of room temperature water, you’ll find that either your sourdough starter floats or it settles to the bottom.
The outcome is indicating whether your starter is holding enough gas bubbles to bring about rise.
If it floats, it’s presumably at its peak activity and contains lots of bubbles of carbon dioxide, the result of happy, thriving, natural yeast.
If it sinks to the bottom, the starter is presumably not ready, requiring further time and feedings before use in your sourdough recipes.
I say presumably, because as I said previously, it’s not foolproof. This might not always be the best way to test your starter’s readiness, but it is a quick and somewhat consistent way.
Tips for Best Results
A mature starter: A mature starter has had the time to develop into a strong starter, ready to work. It has been fed well and is visibly, happily, working. Starters less than 4 weeks old haven’t had time to achieve this.
Gentle transfer: When taking a spoonful to test, be careful not to stir or disrupt the bubbles. We want to keep as many as possible for a fair result. Gently plop this sample into your glass of water.
Peak activity: A starter is at its peak around 4 to 6 hours (sometimes even around 12 hours) after feeding, making this the best time to implement the float test. This depends on the environment and maturity of the starter, of course, and does not refer to a refrigerated starter.
Pancake batter consistency: A thin, runny starter will not trap air bubbles like a thicker starter. Pancake batter is a pretty relatable comparison to a good starter consistency, which will be achieved via your flour/water feeding ratio.
How to Maintain a Good Starter Consistency
A runny starter doesn’t necessarily mean a weak starter, but you also may not get the results you’re looking for in this state. Here are some considerations.
- A thin starter might be one that is consuming the flour and water too quickly due to an environment that is too warm. Can you keep your starter in a cooler place? Direct sunlight is helpful when I’m wanting to promote a quick rise, but it is probably too much heat for your starter’s day to day location.
- It could be that your feeding ratio is off, and you need to increase the flour and water measurements. It’s a good idea to measure your feedings by weight if you’re having difficulty with the consistency. A typical feeding might look like 1:1:1, which is one part starter, one part water, and one part flour. A thin starter might benefit from increasing the flour for a time to a higher ratio, such as 1:1:2.
- In addition to feeding ratios, be sure that you are feeding your starter consistently. If it is thin, it may need to be fed more often. The timing of your feedings will play a significant role in your starter’s condition.
- Another consideration is that whole grain flours will activate the yeast much more quickly, while low protein flour works more slowly. Generally speaking, the more protein in a flour, the higher the gluten content. The higher the gluten content, the more quickly your yeast will get to work and the better your rise will be.
When the Float Test May Fail
Several factors contribute to the float test not being the most dependable.
A new starter: A young starter hasn’t yet developed the strength needed to rise your bread dough. Keep track of its age, continue a consistent feeding schedule, and keep it in a warm spot to encourage activity.
The bubbles were disrupted: When adding a sample of starter to the water, take care not to stir. Gently transfer with a spoon, and carefully place into the water.
Too much contact can pop those little bubbles, causing even a mature, active starter to fail the test when the sample sinks. This would be an example of a false negative – a failed test with a starter that is ready for a bake.
Type of flour: Some flours aren’t as suitable for the float test. Lower gluten flours, such as whole wheat flour or rye flour, may not build a strong gluten network that holds in those bubbles which cause it to float, yet the starter may very well be ready to go.
Past its peak: If you’ve missed the peak of your fed starter before testing, your sample may not float, yet your bake may rise perfectly well.
Consistency: The consistency of your starter can influence its results. Perhaps you’ve tested a young, stiffer starter, and it floats. The thicker consistency can allow more bubbles to be trapped and held, yet your starter may not be ready and you’ll have a bad bake. We would call this a false positive.
Since there are several ways that this test might not tell the full story, it’s a good idea to have other ways of testing.
Find More Sourdough Basics:
- Sourdough Hydration: How To Make Delicious Bread
- How To Bake Sourdough Bread Without a Dutch Oven
- Sourdough Scoring – How To Make Beautiful Sourdough Bread
- How To Store Sourdough Starter
- Maintaining and Feeding A Sourdough Starter
Other Methods of Bake Readiness
Age and history: Knowing your starter’s age and history gives you a strong idea on whether the pass or fail of your starter was warranted. If it’s well fed, produces consistent rises in other bakes, and is several months (or years) old, it’s likely you’re good to go.
Volume test: Measuring the volume of your starter within 6 hours of feeding is a strong indicator of starter readiness. It helps to mark the beginning level of your starter with a rubber band around your jar (or erasable marker, tape, etc).
Approximately 4 to 6 hours after feeding, note the volume of the starter, and whether it has doubled, more than doubled, or remained the same. It’s helpful to be familiar with when the height of the starter is at its peak after feeding, as well as when it falls after hitting its peak. A starter kept in a cooler spot will take a long time compared to one kept in a warm environment.
Visible activity: Another good way to know if your starter is ready is by observing any activity on the top. An active starter will be bursting with bubbles and foam, rather than a smooth, placid surface.
FAQ
What should I do if my sourdough starter passes the float test?
If your starter floats, you can quickly consider the other indicators: do you have plenty of bubbles? foam on top? did your starter double after being fed? is it well-established and not a brand new starter? If you’re answering yes, move right on to baking some great bread!
Why should I use the float test if it’s not foolproof?
If you’ve been attentive to your sourdough starter for any length of time, you’ll have begun to see the pattern of its needs and activity. With this in mind, the float test can be a quick way to double-check or confirm your starter’s readiness.
Being aware of the common issues with the float test, as well as being familiar with your starter, you’ll have a pretty solid idea whether the float test is accurate.
What is the best flour to use for feeding a sourdough starter?
This depends entirely on the individual and their purposes. A young starter does well with equal parts all-purpose and whole wheat flours, a combo that can be continued successfully.
Rye and whole wheat are some of the more nutritious choices, while all-purpose flour is one of the more economical. There are also gluten free options, like buckwheat and rice flour.
Aim for unbleached flours, preferably organic, as the bleaching process generally kills the wild yeast and good bacteria naturally present.
Can I use a deflated starter if I missed its peak?
You can, and I often have. However, if you have the time to wait, you can also feed it again and let the starter rise once more. This would help to achieve more consistent results.
Find Delicious Sourdough Recipes
- Gluten-free Sourdough Starter
- Sourdough Pizza Dough
- Sourdough Discard Crackers
- Easy Homemade Sourdough Pasta
- Sourdough Discard Sandwich Bread
