The Fresh Loaf

News & Information for Amateur Bakers and Artisan Bread Enthusiasts

Sourdough starter not passing float test, doubles in size quickly then collapses 5 hours after feeding...

etw's picture

Sourdough starter not passing float test, doubles in size quickly then collapses 5 hours after feeding...

Hi, I'm new here, trying to make a sourdough starter from scratch - it's now been now over 2 weeks with daily feedings, and I've been using the 1:1:1 ratio.  

After a feeding, it doubles in size, then collapses back to the same level it was at at the start within 5 hours.  

It smells like bread now, so I keep hoping it's ready to use to make bread, but it never passes the float test.

I have NEVER tested it when it was at it's height, but only after it collapses back to its initial level.  Is this my problem?  Is the starter only good to use for bread for a small window of time, and do I need to grab it and use it when it's nearing it's highest level?  

Or do I need to adjust my ratio?

I keep waiting about 24 hours before feeding again - but I am noticing that this starter I'm making seems to reach it's height, which looks like about 2X the initial height, around 4 hours after feeding it.  5 hours after feeding, it's collapsed back down again.  Should I be feeding every 12 hours to hurry this process along?  Or is it still processing and becoming more sourdough-ey for the rest of that time? I just feel like maybe I'm wasting time by waiting to feed until a full day has gone by if the sourdough is definitely not rising any more. 

Any help appreciated!

The photo is of the starter at its height, 4.5 hours after feeding.  I tried the float test just a few min after taking this photo.  When I stuck a spoon in to stir it up and scoop out a blob to drop in water, the starter collapsed back to just a couple millimeters above the starting level.  And the scoop of starter that I dropped into water sunk.

Sourdough starter at its height

proth5's picture

"I have NEVER tested it when it was at it's height, but only after it collapses back to its initial level.  Is this my problem?"

Yes. That is your problem. A 100% or more hydration sourdough starter is ripe when it has doubled and is full of good, healthy bubbles. That means that the yeast still has enough food to keep producing CO2. That's when you want to use your starter - when it is healthy and vigorous.

At a 1:1:1 ratio, your starter will mature very quickly, which is exactly what you are seeing. I no longer use a strict ratio (I've been doing this a while) and in warmer weather will use only what remains stuck to my container to feed 3-5 ounces of flour and water. That's maybe a .001:1:1 ratio.(?) If your starter is reaching maturity too fast, reduce the amount of starter when you feed.

Once it collapses, it is over ripe. You can use it, but the results will not be as good.

Proth5 commenting on TFL...How did that happen? (Someone sent me a private message...) Bye, now!

mothership's picture

Thank you Proth5, you are a wonderful writer, your ability to get through to me is amazing. I get it now, 'though I have read much from other teachers', you as usual were able to give me the 'Aha ooh' moment and am moving ahead today with my S.D. loaf.

What I learned today: It is not that my preferment wasn't ready after tripling in size and very bubbly, it was because I did the sink-water test after I had stirred my preferment.

Secondly: I learned that putting less starter in my preferment at night will give a wider window in which to use it the next day as it rises more slowly. This alone solved a big problem for me because I increased the starter in while mixing a preferment in one of my recipes from 10g to 25g thinking it would give it a kick start, well it did that, but also rose to quickly so my window for using the preferment was smaller.

Well,learning this today was worth many hours of work  and has saved me much trouble in the future. Thank you Proth5, you are the best teacher I have ever had and I hope you stay on line. Learning how to make Sour Dough Bread is not for the faint of heart, but it is worth it. I will be watching for your your answers to others. D

etw's picture

Update!  It's now 4:30.  The starter was fed at 10am.  At 2:30, it seemed to have reached its peak.  I marked it with the blue tape, and it seemed to be coming back down.  So we stirred it up, scooped out a spoonful, and dropped the spoonful into water, where it sank.  The starter collapsed to almost the same level as where it started.  

Now, however, it appears to be rising again.  It's creeping back up the jar.  Maybe it'll be ready 10 hours after feeding?  8 hours?  How do you know how many hours after feeding to wait until you use it / test it?  6.5 hours after feeding, starter is growing again, after sinking a little after 4.5 hours, and then collapsing after a stir

proth5's picture

One of the things I don't like about the "float test" is that your objective is not to get your preferment to float (and before my detractors chime in, yes, I know that a mature 100% hydration preferment will float). You need to understand what you are doing and why. So many food writers think that taking the time to give their readers an understanding is "too intimidating", but that is what leads to your problem. You don't know why or what you are doing.

So this post is long, but it is not difficult to understand. So be patient, read it, and think about what you are doing.

When you take a sourdough starter and feed it prior to making bread, you are making what bakers call a "preferment". This is taking a small portion of the flour in the recipe and allowing it to ferment before the entire recipe is mixed.

This is done to enhance the flavor of the bread.

With sourdough, this preferment will often be the source of the only yeast you will use to raise the bread. You want to make sure that the yeast has thoroughly fermented the flour (to create the taste), but has not fermented it to the point of exhaustion (where various enzymes in the flour will have degraded the gluten).

So when your preferment is ripe, as I explained above, it will double in size and be home to a lot of healthy looking CO2 bubbles. The gluten in the flour allows these bubbles to form - just as they will when you make your final loaf.

But when you stir the preferment, you pop all those bubbles. Imagine poking soap bubbles or balloons. They deflate. And it is the bubbles that allow the preferment to float. Your preferment is still mature,but you have popped all the bubbles and it sinks.

And yes, there is a window when the preferment will be mature. At your feeding ratio, the preferment matures very quickly and the window where it is perfectly mature will be very small. When I use sourdough for my preferment, I use very little starter to the flour and water (see above). This means that the preferment matures slowly and the window is longer.

Your starter is ready to use when it is mature. There is no fixed time for this. I could be 12 hours or 4 hours depending on the feeding ratio and the warmth of the room. There are a lot of variables and this is just something you must learn from experience.

So, you stirred the starter and it started to rise again. Why is this? Remember what you are doing. You are feeding the yeast (and for the sake of brevity I am not going to discuss the whole symbiosis of yeast and lactobaccili that make up a sourdough starter - it is mostly the yeast we are observing here) the sugars in the flour to get it to produce CO2 gas. But yeast is not a terribly mobile fungus. It will digest the food closest to it and once it has done this will start to get hungry again.

When your stir the starter you are putting the yeast in contact with flour that might not have been digested, yet. You will get a rise, but in your typical preferment it will not be as strong or high as the first rise. Typically we want to catch the preferment on its first rise.

So. Takeaway.

  • There is no specific time for a preferment to mature, it will depend on how much of the seed culture is used, temperature, type of flour, etc. You must observe and learn through experience how long it takes your starter to mature.
  • Yes, there is a window for use - and because of the same factors mentioned above, that will vary. But you want to use your preferment after the first rise.
  • Stirring your preferment pops the bubbles and it will not float with pooped bubbles. That it sinks does not mean it wasn't mature and ready to use (which is why I dislike the "float test") it just means the preferment was disturbed.
  • Stirring the preferment will cause it to collapse, but will expose the yeast to additional food and it will rise. Should you ever get to making actual bread, this is the same thing that your bread will do. You will probably see that you should "punch down" or "fold" the bread after it has doubled. You will see your bread deflate (because you popped the bubbles) and then it will rise again. When you shape the loaf, it will deflate and then it will rise again when it is proofed.

I hope this helps. Do not be obsessed with "floating." Learn to recognize a mature preferment. I had a bread baking teacher who every morning would start class with "How do the preferments look?" and if we didn't know we got the evil eye. It takes time, but once you get the hang of it, it is all very simple.

I'm going to walk away from TFL now (and probably for the next year or more). If you want me to answer any more questions, you must reply to my post.

loaflove's picture

Totally agree with proth5.  I no longer do the float test.  and just rely on visual assessment. sometimes blobs from the same starter will float and some will sink depending on how much air the blob has.  Tired of cleaning little blobs of starters from my glasses. 

spabbygirl's picture

that was really helpful to me too. Have a relaxing break and hope to see you back Proth5

Ksroberts's picture

Thank you for this explanation.  I love knowing the whys/hows behind break baking. 


Maria Morando's picture
Maria Morando

Your post on float tests is very informative. I would like to know however, in the past I could easily spoon a portion of my matured starter into a bit of water and got lovely float results. I would not get the best baking results though. I felt it was just not strong enough. I now have what I believe to be a strong starter, and when I spoon it out into the water, I see it sink a bit or more every time. I was wondering if you may have an explanation for this. It makes no sense to me because it is very elastic and shows tremendous gas production and gluten strands when I spoon it out. I feed it regularly throughout the week and keep it refrigerated as well. Then when I am ready to use it, I feed it three more times on the counter in the course of 2 days. I haven't been trusting it because of the float test, so I have been adding a little over 1/2 tsp of yeast as insurance. I am getting some of the best bread bakes with open crumb perfect moisture and great taste, but I wonder if it wouldn't be so without the added small amount of yeast. I don't understand the float test failing over and over again at this time. I keep a flour mix for my starter of one part rye, two parts of high protein white organic bread flour, and two parts of strong whole wheat flour finely ground. Should I try a different mix of flours, or should I forget about the float test?

proth5's picture

but I really don't have definitive answers for you.

There are so many variables. "Sink a bit" - you mean down to the bottom or just not the nice floaty position of your younger starter?  If it is just riding lower in the water, I wouldn't worry.

The question you need to ask yourself is: What changed? Is ambient on the counter warmer, did you change the flour mix (or flours)? Are you letting the starter mature longer or shorter? Something changed - even if it just the maturity of the starter (and starters that are fed whole grains will get sourer with age and often people who keep them will "start over" from time to time). Or how you have to spoon it because it is so elastic? Something changed and you would be the one to understand that. The one thing that these prescriptive folks miss (and I see a lot of this in popular food writing) is the need to observe, observe, observe. I'm using my starter - does it seem the same as it did last time? I've mixed my bread - how does it feel? How does it smell? Does it seem to be rising at a good rate? Does it feel "live" under my hand? It's a living thing. What is going on with it?

Not being a fan of the "float test" - I would say if the starter is elastic and it has tremendous gas production (and it has about doubled), I would consider it mature and not worry if it floats.

As for the 1/2 tsp of yeast - that's hard to say because you don't specify any other measurements for your bakes. But, success is success. If you like your breads you can continue that. The best thing to do would be to do a batch with just your starter and observe how it goes. I know people can get scared about having a "failed" bake - but if you are not failing, you are not learning.

Hope this helps, for what it is worth.

mothership's picture

Proth you write beautifully, thank you for this. You were the right person for me to read at this point in my learning on sourdough bread and I have come away with a renewed understanding. Unfortunately, I only have what you wrote in this column, but I do hope you will return to this site sometime in the future. It was a pleasure to read and learn from you. Sincerely, D.

proth5's picture

for the kind words. See below.

loaflove's picture

Sorry , i haven't read this whole thread so if anything i say is redundant i apologize. When i first started out making sourdough i was always doing the float test.  TBH , I discovered it's totally unnecessary.  As long as your starter doubles or more, you can use it. 






Maria Morando's picture
Maria Morando

Thank you so much for your response. It is very helpful. I did change my flour mix for my starter. I use a 1:2:2 mix of rye, high protein bread flour, and finely ground high protein whole wheat flour respectively. Before with my previous starter, I used a 50/50 mix of white bread flour and whole wheat flour. Both those flours were slightly less protein than the flour I am now using. My current starter smells wonderful and I change the vessel from time to time to keep it fresh. My previous starters did not create the greatest breads. They were more fluid when I removed them from the container to the recipe, but they always floated. My current starter from my last bake did not float at all. It sunk right to the bottom. But it looked and felt so elastic and strong and full of pockets of air and produced lovely stretchy gluten strands. The bubbles from the outside were not real big, but they were present throughout. The levain expanded to about two and a quarter times. I just don't understand why it did not float. I made two medium sized loaves of bread, and they had tremendous oven spring and produced a soft even open crumb and the flavor is great. I have a hard time believing that 1/2 teaspoon of yeast added to my 200 grams of starter is responsible for all of that. I did a 2 hour autolyze, and put my recipe together and stretched and folded for about 2.5 hours. I think the yeast speeds up the process of bulk proofing. When it was clearly puffy, but not fully proofed, I shaped my loaves and put them into the bannetons. I put them in the refrigerator overnight. They rose some more, and I baked them from the fridge. My bakes don't seem to be following the conventional wisdom and I am trying to learn not just from my failures, but I would like to learn something from the success of what I am witnessing. 

proth5's picture

I'll start my post with the kind of crabbiness that has caused me not to post to TFL much these days. Yes, a 100% hydration starter made with wheat flour will float when properly mature. This happy coincidence has somehow taken on a life in the minds of mass market food writers and has morphed into a "float test" - something that must be passed in order to know if a starter is ready to use. I studied with bakers whose names most serious home bakers would recognize (who I will not name because then I get accused of name dropping) and never heard of such a thing until it popped up in popular food writing. One recognizes the maturity of a starter in other ways - doubling, being full of bubbles, creating a dome (this is for firm starters). The thought of scooping out a spoonful of starter, putting it in a vessel of water and seeing if it floats, simply makes me tired. (And while I am being crabby, videos of "double lamination" that display an elegant and masterful technique for doing stretch and fold,shaping, and putting inclusions in bread, but contain no lamination whatsoever - because lamination is a technique where fat is enclosed in dough to make layers that will puff in baking [consult references like "Advanced Bread and Pastry"] - make me want to weep.) Anyway...

You have named your change. You have added rye to the flour mix that you use to feed your starter. While rye brings many good things to a starter (a nice dose of wild yeast, flavor, sourness) what it does not bring is the gluten that supports the extensibility to make large bubbles in the starter (which, again, you have observed). The bubbles are smaller, Your little spoonful contains more solids than an all wheat starter in proportion to the gas. It is denser. It sinks. Which doesn't mean that you do not have a mature starter with enough yeast activity to support bread making. You do. It just sinks.

if you add commercial yeast to your dough, all phases of fermentation will go a little faster. Also oven spring is improved as the last gasps of the rapidly metabolizing commercial yeast will create more gas than the wild yeast which will be creating gas, but at a slower rate. You seem to have a healthy starter and probably do not need to add commercial yeast - although you will find that everything takes just a little longer.

You are making nice bread, but what you are observing is quite predictable if you understand the fundamentals.For you starter you need to forget about the float "test" - it simply doesn't apply.

I need to walk away from this, because my crabbiness is showing...

Maria Morando's picture
Maria Morando

I don't think you are crabby at all. I think your words are thoughtful and measured. I do want to get another opinion from you, if you would be so kind as to offer it. Do you think it would be a good idea for me to stop adding rye flour to my flour mix? I can go with the straight 13.5  percent white bread flour and the 14 percent fine ground whole wheat flour. I could just mix them 50/50. I only added the rye because I keep hearing people say it is good for adding activity to the starter. But maybe it is not contributing anything to my bread?  I agree with you that I also get crabby sometimes. I get a bit confused by so many different techniques, and everyone touting about how they have the art of sourdough figured out. So many of them are baking beautiful bread, while doing it differently from one another. Maybe sourdough isn't as one dimensional as many people make it seem. As long as we stick to the basics, maybe there are more than a few successful ways to make it.

proth5's picture

Rye flour is often used when starting a sourdough culture because rye carries a lot of yeast with it (as long as we know that the yeast comes not from "the air" but is carried in by the grains we use in the initial culture) - a bit more than wheat - and that yeast is somewhat compatible with wheat yeast. I really can't remember if I used it in my sourdough starter in its infancy - it was a long time ago.

Most people stop using rye flour in their wheat flour starters when it has come to the balance point where the starter is stable.

Some people keep a starter of all rye flour because they bake rye breads often and feel that a rye starter performs "better" in high percentage rye breads.

I, personally, keep an all white flour starter, fed at a ratio of ??/1:1 - which means I generally don't know how much seed culture I use, but it is way less than the 1:2:2 I am often seeing on these pages. I want my starter to mature in 12-16 hours (most of the time) and not be totally exhausted in 24 hours, when I will refresh it. My starter lives at whatever room temperature may be in my house - and that varies widely. My seed amount varies with the weather. I've gotten very good at guessing what my starter needs and generally, when I am ready to do a mix, my starter is ready. I prefer a white flour starter because it is easy to maintain. It is also very versatile as I incorporate it into a lot of different things including sweet doughs and laminated (really laminated, like croissants, not whatever the word seems to mean around here) vienoiseries. When I want a whole wheat preferment, I use my white flour starter as the seed. When I want a rye preferment I use my white flour starter as the seed.

That's what I do. That's what suits me. That's what I want.

But what do you want? When you used only wheat flours, you seemed not to like the results. You added rye and now you like the results. Why ask me, then? What do you want? How will you use your starter? What will make you feel that you are producing good bread. How much effort do you want to put into maintaining your starter. You don't need my advice- you can decide for yourself.

You are correct. There are basics (using words correctly comes to mind, but I digress...). You need to understand dough development, the functions of all the parts of a yeast dough, and the life cycle of yeast dough. It helps to understand Baker's Math (Well, actually, I feel it is essential to understand Baker's Math, but many people make many nice loaves without understanding Baker's Math. I baked for more years than you can imagine without it. Upon having it explained I actually cried out "Why did no one tell me about this before!" It made sense of all those thousands of recipes in an instant.). But the details are as varied as the bakers who use them.Take dough development - some people swear by "slap and fold" - where you actually pick up the dough, slap it on the bench and fold it over. Personally, I think that's a lot of work. If I'm not using my spiral mixer (yes, I have a spiral - lucky me!) I use a technique that involves using a bowl scraper to fold the dough over itself in a bowl 10 or 12 times and then letting it rest for 20-30 minutes and then repeating that 4 or 5 times. It takes time, but doesn't take much muscle. I can develop 5 kilos of dough with nothing but a bowl and a plastic scraper. Or, I've used the "stretch and fold" method where you grab two handfuls of dough, forcefully stretch it and fold it over itself. Done correctly, it is very effective (I did have a teacher say in a class "you all stink at folding - all except proth5" so I know I am doing it correctly.) And there are many other methods, including the traditional kneading that you can find in the Betty Crocker Picture Cookbook from the 1950's). I am fortunate to have learned so many, so I can decide which works best for me. The person who says "this is the only way" is simply displaying their lack of knowledge, because they all work just fine. What is important is that in the end the dough is properly developed - and proper development for the dough in question is the part that is not variable.

My most heartfelt suggestion is that you find a baker with excellent credentials and take a class from him or her. There is no substitute for standing at the side of the person and feeling the dough (My teacher once asked the class I was in to decide if a batch of loaves was ready to go into the oven. He refused comment from anyone who had not put their hand on the dough. I learned that lesson quickly.) Failing that, get a book by a well credentialed baker - both "Bread" by Jeffrey Hamelman and "Advanced Bread and Pastry" by Michel Suas come to mind, but I'm sure there are others. These are books written with utmost respect for baking technique and not with a slick emphasis that says "Gee whiz these are pretty pictures - I'm some baker, I am!" The books should explain the basics and strive for understanding, not just say "do this or do that."  AB&P is quite a tome and is written for professional bakers. It includes a lot of information on bread, but it also includes vast sections on pastries, chocolates, confections and sugar work and can be overwhelming or may simply be more than you need. My life would be much diminished without it, but I also do pastries, chocolates and confections.

So that is my non-advice advice. Learn, grow, observe, and decide how you want to bake.


Maria Morando's picture
Maria Morando

You are so kind as to take the time to address my concerns about my starter. I thank you so much. I live in North Carolina, and I am willing to travel to another state, or throughout North Carolina to take a class in sourdough. I have no one near me who teaches sourdough classes. I was wondering if you know of someone that you respect and has knowledge of sourdough bread baking that I could travel to and take their class. If not that is okay, I will keep reading and learning.

Thank you for your advice. I do appreciate it.

proth5's picture

nothing is happening right now. Once this is over, I suggest you look into the Baking Education Center at the King Arthur Flour Baking Company. It is in Vermont, which is a pleasant place to visit.

Another good source for classes is the Bread Bakers Guild of America (at Their classes tend to be more advanced, but are located all over the country. You can see a partial list of classes (which are currently "virtual") without being a member. If you decide to take a class, your membership fee is included in the price.

Also look to local culinary schools, which should be a search you can do easily. With sourdough being so popular right now they may offer one off classes on sourdough baking.

Hope this helps.

pmccool's picture

Here are some possibilities, Maria.  Note that I don't have first-hand knowledge of any of them, so can't offer any reviews or critiques.

There are also a lot of classes available on-line now that previously required students to be on-site, so look into those, too. 


Maria Morando's picture
Maria Morando

I want to thank you for your suggestions. I have been to LaFarm, and they have delicious bread. I will inquire about both classes. I think they are not scheduling classes at the moment because of Covid, but I do believe that they will start up again once things start to clear up. 

alfanso's picture

I usually steer clear of levain related discussion because the more knowledgeable sorts on TFL are better equipped.  However.  I am also in the camp of not bothering with float tests.  Haven't performed one in years.

Should all levains respond the same when tasked with a blob of it dropped into water?  What about a 60% hydration AP levain vs. a 60% hydration rye vs. 100%...vs. ...  You get the idea.

A while ago, just for fun I posted the experiment in this link.  It isn't about float tests, but rather how a few different starters respond when fed over the course of two consecutive builds.  It gives a window into what differences there are and particularly what expectations to have with these types of levain when they build completes.  Not scientific by any means, but I think there is enough experimental/anecdotal in the blog entry to be of some value.  And to inform that differing levain compositions may not/should not perform the same in a float test.

Maria Morando's picture
Maria Morando

Thank you for your reply. I will go to your page where you performed your experiment. I am sure that it will be helpful.

Kerry's picture

I'm with Maria on your 'crabbiness'.  A very skillful carpenter I knew in my past expressed gratitude in learning his trade from 'an old guy' where he learned a thing was either right or wrong, never "good enough".

I'm crabby too.

Pax Christi