The Fresh Loaf

A Community of Amateur Bakers and Artisan Bread Enthusiasts.

The Float Test

JenMayer's picture

The Float Test

Hey Everyone!

Quick question about "the float test". I have recently read that a good way to test if your sourdough starter is ready for baking is by performing a float test (dropping a small amount of starter in a cup of water to see if it floats). Until now, I have been just feeding my starter and seeing if it doubles in size before I bake with it. In your opinion, what is the best way to know if your starter is ready for baking. What are your thoughts on the float test etc.? Thanks y'all!

Lechem's picture
Lechem (not verified)

Although I've yet to do one. I've just gotten to know my starter, how it behaves and how it should look. I winged it at the beginning by following recipes and using their guidelines. Troubleshooting the inevitable flops when first starting off. And now I go more by feel. It has been a learning curve. Now the starter maintenance and build has become more second nature leaving me to concentrate more on the dough stage and particularly final proofing which is, in my opinion, the most difficult to judge.

lepainSamidien's picture

The float test will let you know if there is enough gas in your starter to permit it to float, and 99% of the time this will indicate that your starter is ready to make some darn good sourdough bread. But we cannot forget that there exist other CO2-producing bacteria and/or yeasts that will not necessarily yield darn good sourdough bread ; for instance, in the toddlerhood of a starter (2-4 days in), before it has developed sufficient acidity, there is a certain strain of bacteria or yeast that produces CO2 that makes the flour-water mixture rise and would conceivably pass the float test. It is not impossible that this particular strain could reappear in a starter, though highly unlikely. HIGHLY unlikely.

So if your starter is well established, the float test is pretty foolproof. However, if you don't feel like doing the float test, and your starter is doubling reliably and smelling fine, then skip the test and pass right on to mixing up your dough. I won't tell if you don't.

pmccool's picture

I won't go so far as to say "don't" but I would ask: What might make the float test unreliable? 

If the levain is fairly high hydration, and/or mature, and thus cannot maintain its structure when it is spooned from its container to the water, it may very well sink instead of float.  If it sinks in such a situation, does that mean it is unready for baking?  Not at all.  Whether it sinks or floats is dependent not on the initial amount of gas it contained but on the amount of gas it contains when it hits the water.  If too little gas is retained during handling, the levain won't float even though it may be at the perfect degree of ripeness for the recipe.

"Ready for baking" is one of those "it depends" concepts.  Does the recipe call for a young levain?  A mature levain?  Or something in between?  Does the recipe call for a liquid levain or a firm levain?  Some of those might float at the prescribed state of readiness, others may not. 

It is best to read and understand what the recipe writer intends (if they've done a good job of describing things) and then proceed as directed.  The one thing that is always helpful is to ferment the levain in a transparent container with vertical walls so that you can see how much bubbling or expansion is going on.


suave's picture

Neither is 100% reliable.  Float test will only work for relatively stiff levains, anything above 80% or so will probably just disintegrate and sink.  Doubling is also a dubious criterium - there are starters that more than double when they mature, while others never reach this mark.

Lazy Loafer's picture
Lazy Loafer

On the other hand my starter is always at 100% hydration and it floats beautifully pretty much every time I build a levain with it. Soft, pillowy and bubbly, and it doesn't disintegrate until I mix it into the water.

oo7wazzy's picture

HI Jen

I started a starter 2 weeks ago and have gone through a few different stages from having hooch form ontop and been quite runny consistency to a seriously aerated, bubbly starter that doubles in size. But i still have no success with the float test. The dough keeps its shape in the water but does not float. I tried a country style loaf after a week using the starter and it didnt rise at all, so i want to pass the float test before i try again, just going to keep on feeding it and see how it goes.

Danni3ll3's picture

I would go ahead and use it. Make one loaf as a test and remember that sourdough takes longer to rise. Good luck!

oo7wazzy's picture

Thanks Danni

ill be brave, haha... 



Lechem's picture
Lechem (not verified)

Your typical starter build and at what stage you try to bake with it? 

Ru007's picture

I've never used the float test, so i agree with Paul and Dab. Its not the only sign that a levain is ready, but it clearly works for some people. I think you just need to get to know your starter and how it tells you that its ready.

When you say your country style loaf didn't rise, do you mean the dough didn't rise, or that you didn't get any oven spring when you put the loaf in the oven?

Maybe talk us through the steps you're taking when you try and bake a loaf. 

dabrownman's picture

There are many starters/levains, made exactly the way the recipe calls for, that will never float.  Other recipes call for a starter that will float.  Both are fine and perfect for the recipe at hand.

My favorite levain is a 100% bran one that won't even rise.... much less float:-)

Happy baking 

jeffbellamy's picture

What if you just fed your starter so it is "not ready"? Why couldn't you just use it and lengthen the  and Bulk rising?

Lechem's picture
Lechem (not verified)

I have often thought about this. 

mlw03's picture

I've used the float test with good results.  My starter is 1:1 flour:water, and if it floats (usually 8-10 hours after I feed it, coming from the fridge) then I get good activity from it.  The times it's failed the float test and I proceeded anyway, the results were poor.  So for my starter it works, but from reading the above explanations I can see why it might not for some people depending on the nature of their starter.