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My starter smells like acetone.. Is something wrong?

Michael PD

My starter has developed a strong acetone smell. It's a little more than 2 weeks old and has been raised on an equal mixture of organic rye and spelt flours. Is it normal for a starter to smell like this? ..or has something gone wrong, as if so what can I do to fix it?

203 users have voted.


LeadDog's picture
LeadDog 2010 January 11

Tell us your method for feeding it.  How much do you throw away?  How much do you save?  How often do you feed it?  How much water and flour do you add to it?  Where do you store it?  Anything else that you are doing to it.

Michael PD 2010 January 11

I've been feeding it roughly 100g of flour and 100ml of water every day (but usually not the same time each day due to other commitments) . I throw away almost all of it except for about a table spoon worth. I keep it on the kitchen bench in a glass container covered with a damp tea towel.

LeadDog's picture
LeadDog 2010 January 12

 Ok I would say it isn't being feed often enough.  Try feeding the starter twice a day.  That should make the smell go away.

dimitry1 2010 January 12

I had a starter that I converted to 100% Rye and it was 1 part flower 1.5 parts water, after few days it satrted smelling, I started to feed it avery 10 hour, one time in the morning one time at night, smelled went away and the starter was great. Just baked some bread using it turned out grea, by the time I gave a loaf to all the guests at my house I was left with 1/2 a loaf of bread. But it was fun to bake it, next time I'm baking 30 loafs.

Head Baker 2010 January 12

 the golden rule with starter dough or basic rye sourdough is, that the  colder and harder (24 degree dough temperature and 100% flour and 50 % cold water) the dough is the more strong is the flavour ( almost vinegar smell)  the warmer and softer the more  lighter is the sourdough ( 32 degree dough temperature and warm water 100% flour and 60 % water) 

you need to have your  starter culture this one is:

step one, 1 part rye and 1 part yoghurt and 0.5 part warm water u mix it and u keep it on room temperature,

step 2: the next day ( 24hrs) u add  1 part rye and 1 part warm water and again on room temperature 1 day ( 24hrs)

repeat step 2 one more time until the whole mixture start to become bubbles and start to smell lightly sour. 

and now from this so called rye starter culture  u take 20 to 30 % and u mix it with 100% rye flour and 50 to 60 % water ( like mentioned above...hard and cold is sour  warm and softer is more light..the reason is the working process of the lactose bacteria with the different dough temperature) 

make sure ur bowls and mixture is clean and tidy and there is no other flour ( wheat flour) or other things except rye flour starter culture and water in the mixer

mix just untill all ingredients combine..maybe just 4 min slow speed thats enough

the starter dough is read between 15 to 18 hours.  a rye sourdough u never refresh twice a day. if u dont need all u can keep it in the chiller or even freeze it but for  privat baking  u keep it in the chiller... 2 day before baking u take it on room temperature, 1 day before u  refresh / or feed it and  here we go u can bake your bread :)

For the refreshing part you use 30 % from the old basic  sourdough plus 100% rye flour and 50 to 60% water ( for example: 500 gm rye 250 gm water and 150 gm old basic sourdough. you have now 900gm sourdough..750 gm u can use for bread and 150gm u need to keep for the next refreshing. just as example :)

An old baker trick if the sourdough has "flipt over"  means  becomes the acetone taste yours that you add a  diced or better ground onion in the refreshing part, the acid in the onion will take care  of the acetone smell :) or you can add vinegar to the refreshing part.

But my personal advice is, if u doing it for your private amusement just through it away and start again like i mentioned above from within 5 days u can bake a new  bread :)

sourdough likes to have it warm,  clean and enough resting time and again...15 to 18 hours between refreshing and using it in a bread is enough

i think that should work :)

good luck and happy baking 


Sourdough Newbie 2010 January 25

I'm new to the starting and keeping sourghdough thing.  My starter smelled strongly of acetone but had no discoloration or mold, and even bubbled well when fed and mixed.  The cookie dough I made with it didn't rise and with the research I've doen so far it seems the bacteria has taken over the starter from the yeast.  My concern now, is it safe to eat the cookies made from this starter or should they be tossed.  I don't want anyone poisoned by my ignorance.


dimitry1 2010 January 25

I have a starter that smelled like that but I threw most of it out and fed it few times and it was fine. My bake  with out a problem, so i don't know if the cookies would be bad, I would asume that if you baked them they should be fine.

Bread Or Alive 2010 February 9


Mine is the same, a spirit-like smell. Did you have any luck sorting it out? Was it more feeding? I am throwing most away every day, but the smell has been constant for about two weeks now. Any help appreciated....

Giffy's picture
Giffy 2010 February 26
My white flour starter is all acetoney tonight. I believe it can be salvaged (if not I have a wholemeal one I can use), but I'd like to know how - do I just feed it twice a day for a few days until it smells yeasty again? Should I store it on the bench or in the fridge while I do this? I had previously discarded a starter that did this. I'd kind of like to know what I am doing wrong - I usually keep it it loosely covered in the fridge and feed it once a week unless I want to use it. If I want to use it, I feed it, then 8 - 12 ours later I start my sponge.
Carter 2010 March 15

I am at day 4 of beginning my starter and by the end of each 24 hr period it appears to have a faint pinky colour to it. Is this OK, or should I toss it and start again?

LittleMonkeyMojo 2010 March 16

I commented on your other posting, but figured I'd comment here so the answer would be available in this thread as well...

Pink is bad.  It means that your starter has turned evil.  This is probably because of developing mold or picking up some other, conflicting, yeast or bacteria.

Starter with a black liquid on top is fine, you can stir that liquid back in, or pour it off, up to you, it's mainly alcohol (I don't think you'd want to drink it).

Clean your container well before using it again.

I'm curious as to your feedings.  You say you're keeping about a tablespoon and adding 100g flour, 100g water.  This doesn't seem right to me.  The recipes I've looked at generally fall into two camps.  Camp 1 says if you have X grams of starter you add X grams of water and X grams of flour.  Camp 2 says if you have X grams of starter you add .5X grams of water and .5X grams of flour.  Me, I've tried both ways and didn't see a major difference so am leaning toward the side of least cost.  If I have 300g of starter I'll add 150g water and 150g flour.  If I have a massive amount of starter I will dump most of it, keeping at least 100g, and feed it according to formula.

When I'm not baking I will put my starter in the refrigerator.  When I'm planning on baking I pull the starter out a couple days prior and give it a feeding.  Wait till it's doubled and then dropped back down, then another feeding.  Usually the first drop is around 18 hours later.  After the second feeding, the rise and drop is quicker, I attribute this to the starter getting back to room temperature.  You can back after the second feeding has risen, but I usually try to wait till the third feeding.

You say you keep your container covered with a damp cloth.  This seems wrong to me and might be the reason your starter went to the pink side (doesn't sound nearly as evil as the dark side).  Rather than a damp cloth I'd recommend plastic wrap (cling wrap, saran wrap, cling-film, glad-wrap, whatever it's called where you are).  You want it covered, but not absolutely sealed.  Gas pressure will build up and you want that to be able to vent.

I hope the next batch goes much better.



CayoKath 2010 November 26

Throw it out.  I keep commercial yeast around for just-in-case, although I have high hopes of a years-old starter.  That may not be possible, though, with my erratic feedings.  Tomorrow my task is to get a brand-new glass jar with a latching lid and start again.  I lost one starter recently to pink mold and just pitched one today that was obnoxiously acetoney.  Part of that is the "politics" of husband catching a whiff and being very worried I'd poison us.  I've saved an acetoned starter before, but he wasn't privvy to it.  It was a good one, too, until a moth got into it. 

Otak 2013 October 28


I have recently baked my fist sourdough bread with a starter by the recipe of Paul Hollywood who uses grapes. I have read lots of info from this community/website which made me even more enthousiastic. My first bread turned out pretty good so now I'm planning to bake much more often and trying out different breads.

However, when using my starter I poored it out of my jar. A few days later I noticed there was some mould on the side of the jar (on the inside) where some remains of the starter were left on the glass. Is this something that happens often? I am not a big fan of mold or germs in general so I might be over-reacting here but does anyone recognize this and can I wipe it away without having anything contaminated?

Also: I wonder how other people do this, do you wipe the inside glass after having poored it out or can there just be some starter-residu on the sides which hardens out a bit (and thus maybe go mouldy).

Bye! "Otak".

farinam's picture
farinam 2013 October 29

Hi Otak,

Not all moulds are bad - just think blue cheese.  However it is a bit unusual in my experience. 

There is nothing wrong with having remnants of starter up the sides of your container, just not aesthetically pleasing.   The acid (sour) in the starter is a very good inhibiter of mould growth and possibly the environment of the dregs is not acid enough.  

I use a small soup ladle to dip mine out which minimises the amount that gets up the walls and after I stir in the new feed, I scrape down the walls to return any starter/flour dust to the bulk and give it another stir to incorporate it.

If you don't have a small ladle then maybe you could just try the scraping approach.

The other thing I would do would be to take a quantity of your bulk starter out (try to avoid any obvious mould areas) and dump the rest.  Then give your container a good clean and sterilisation and rebuild the bulk using the quantity that you reserved just to try to make sure that you minimise the amount of mould spores in the system.  Then by keeping everything in the acid environment of the bulk starter the regrowth of the mould should be stopped.

Let us know how you go and good luck with your projects.


AbigailSwayer's picture
AbigailSwayer 2013 November 1

This has been one healthy discussion. I got to know may things about starters which were not known by me earlier. I would say that the posts have been myth busters for me. Also adding grapes was one of the best tips ever known to me. Thank you all.

Gabelous 2013 November 4

I have had my own culture from my own area in new England for two years now. A week down on the Outer Banks NC gave me the chance to capture another starter. While I did flub up the feedings during the week I did catch some yeast and lactobacilli. But it does have a very strong alcohol scent and it takes more than 24 hours to rise. Even then it doesn't proof nearly as well as my native culture. Trying to figure out what is going on, there is no pink mold or other external signs of invasion/infection. But it smells very acetone, very different from my native culture.

I will take some advice here and see if I can feed it more consistently and see if that works. The yogurt sounds like a good idea to give the bugs a more healthy food source to start.

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