The Fresh Loaf

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Starter with a Rotten Egg aroma

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Janetcook's picture

Starter with a Rotten Egg aroma

I have been experimenting with keeping my kamut/wheat and rye starters out on my counter rather than storing them in the refrig. for the past week.

My rye starter has a very pleasant aroma but my kamut/wheat has a bit of a rotten egg aroma to it that puzzles me.  (My starters in my refrigerator usually give off an alcoholic aroma after being stored for awhile so this is a new fragrance to me....)

I have been taking 5g of starter and giving it 5.5 grams of water and 8.5 grams of flour for a hydration level of 63%.  It is stored on my kitchen counter where the temp. varies according to the time of day.  It can fluctuate a good 10° in any given 24 hour period.  

I have been feeding it every 12 hours unless the temps have been a lot cooler then I have let it go 18 hours.  ( I judge feeding time by how it looks. I roll it up into a firm ball after it is first mixed and once it has relaxed and softened I feed it.)

These are both mature starters and I have been using them for several months now.

If this is a 'bad' thing, I do have back up starter in my refrig. and can use it but I wanted to check here first before starting a new counter batch...

THanks for any suggestions.


clazar123's picture

I doubt you'd poison anyone but still-why take a chance.If you have doubts then toss it. Starters can have lots of smells but rotten eggs isn't one.

Regarding other characteristics:

Is the color "off"?Is it an old cheese type of smell? Is it rather watery even after thickening it up with a feeding? That is a bacterial contaminant growing and producing all kinds of enzymes that digest the flour. Not good for breadmaking.

Janetcook's picture

Color is great and so is the consistency. Looks and acts just like starter....just the hint of rotten egg once it hits peak and beyond.

Last night I tried doing a 10:10:10 feeding to see if it made a difference. It is a very strong starter and had just about doubled in about 2 hours.  I put it in the refrig. because I was headed to bed and didn't want to let it ripen any more without me being able to observe it as it changed. It smelled fine at that point.

This morning I took it out and am letting it warm up on the counter before I feed again at the same proportions to see if it changes any before I dump it....The egg aroma is there but not as much as it was before.

As you suggest I won't use it in baking unless it shapes up....but I am using it as an gather more information about starters since I am very new at this and REALLY new at leaving them out on the counter.


cranbo's picture

I agree that it shouldn't smell like rotten eggs (probably some bacteria in there) but I wouldn't necessarily throw it out.

Personally I would rebuild it starting with 5g of the starter, then 50g of flour and 32g of water, feed it like this 1x every 12 hours, and see if the smell goes away in 2-3 days. 

If it's not visibly moldy, it's probably still usable, but it sounds like it's not too happy right now. 

Janetcook's picture

We must have been writing at the same time.

Why would I feed it at the amounts you stated?  Do they favor yeast development over bacteria development and hence balances it out?  I haven't fed it yet so I will wait to see what your explanation is so I can try your method and know why it is doing what it is doing....

 I thought to get a starter balanced again equal amounts of all ingredients were recommended....can't remember where I read it but that is why I did the 10:10:10 thing...



cranbo's picture

Hi Janet,

Yes, I do believe that by diluting the starter with a significant amount of food (flour and water), you give the good yeast a chance to thrive, so that hopefully it overtakes (and eventually drives out) the bacteria that are causing the unpleasant odor. 

The quantities are essentially a scale of 10x greater than your current starter feeding, while still maintaining your 63% hydration. I figured a power-feed might help drive out the bacteria. 

At 10:10:10, you would have a 100% hydration starter and be feeding 5g of starter with 5g flour and 5g water. Liquid starters do help yeasts thrive, but they might let the bacteria grow too. Then again, it may be that the firm starter that you maintain enabled growth of the undesired bacteria, and a more liquid starter might help get the yeast and acid levels in balance to drive them out. Firm starters are supposedly more conducive to yeasts which produce acetic acid, while liquid starters are more conducive to yeasts which produce lactic acid. 

Of course, you could try both out and see what happens, and which technique causes the nasty smell to go away more quickly. I'd love to hear what worked for you!

And if all else fails, I recommend considering feeding with some pineapple juice to help re-acidify the environment .

Janetcook's picture

Thanks for the information.  After reading your previous post I looked around in old threads to see if I could find any more information on feeding to balance things out.

My search was rather random and I came up with several ideas that confer with what you have stated above.

Based on what I read I did feed again but not quite as big of a leap as you suggested.  I did a 1:4:5 ratio starting with 5g of starter.  I got these ratos off of a forum piece by bwraith on maintaining a starter.

In another thread, I can't recall which one, someone mentioned the acid piece you wrote about and recommended using clean hands when mixing rather than utensils as the bacteria on our hands tend more towards the lactic strain than the acetic critters.  I did that.

The final piece I got was in relation to temperature and hydration.  Seems that dry, cool environments favor the acetic acid over the lactic acid.  That really fit for how I have been maintaing this starter.  After feeding I put it out into our family room on a shelf by the fire where the temps are in the mid 70's.  (Kitchen counter temps range from 64° - low 70° only)

It has been 2 - 3  hours now and my starter is growing.  I know the yeast are strong.  The aroma is still pleasant and that of wet flour.

It is rewarding to know what is happening and that I may be able to 'help' my starter out provided I respond appropriately.  You have given me a great lead to follow and now to wait and see what happens.

If all works out I think I will start keeping my 'counter' starters in my oven with the light on so that they have a more stable environment ...The fluctuations in temperature just maybe too much for them to deal with....The rotten egg aroma being their way of trying to get my attention.  :-D 

HUGO's picture

Janet in all food service use the rule '' WHEN IN DOUBT, THROW IT OUT ''.

For almost a year i used a '' SOUR DOUGH LADY PINEAPPE STARTER '' It levined as good as yeast''.  However, not much sour taste.   I tried everything even vinegar!  Two weeks ago I decided to try a FRESH GRAPE STARTER.   I crushed 1/2 lb store bought from CHILE red seedless grapes, added 1 cup unbleached CAF and 1 cup of well water from my system, mixed it all up and let it ferment 5 days at 65 degrees room temp.   I then strained it w/ a callander into a glass covered jar adding 1 cup flour and 1 cup water.  next day i just added flour as it was soupy. Once the tiny bubles appeared I fed it daily to the constency of a thick batter.   A bout day 10 I took 1 full cup of starter as follows;





1 tsp SEA SALT











cranbo's picture

pretty funny advice in the same thread:

in all food service use the rule '' WHEN IN DOUBT, THROW IT OUT ''.

and then


Happy the bread turned out well anyway though!

gary.turner's picture

That's a good sign your yeast is underfed. It's a by-product of trying to digest proteins (even its own) due to a lack of available carbohydrates. It's called ketosis or acetonemia, and is something diabetics, and others on a low carb diet have to watch for.  Ketones will be reabsorbed by the yeasty beasts if well fed for a while. A further by-product, resulting from anaerobic bacterial digestion of the esters, can be butyric acid which gives off a rancid butter aroma and taste. Only a very small amount of the butyric acid will be re-absorbed. Probably, continued refreshment of the mother will rid the culture of this foul smelling abomination* (it has its uses, in cheeses for example, but not in sourdough), but better not to underfeed the culture to begin with.



* It only takes about 10 ppm to be noticeable.

LeadDog's picture

I agree the starter is underfed and has run out of food.  The yeast are eating themselves.  The same thing happens in winemaking.  We will have batches of wine were the yeast run out of nutrients and a rotten egg smell will start.  We just add some yeast food and the smell goes away.

Mini Oven's picture
Mini Oven

I've mentioned it before and I will mention it again because I think it's worth mentioning.

One level teaspoon or 5g of starter is not a lot to work with.  It will work but Weird things tend to happen more often than when using 10g of starter or a more rounded to heaping teaspoon.  It might have to do with margin of error on the ripeness of the starter.   

There was a time when some of us old timers were having lots of experiments going and found that 10g was about the lowest we would go for an inoculation in cooler temps.  

Here is a Link:  Enjoy uestion-about-how-recognize-ripe-levain

Janetcook's picture

Thanks for the link Mini...

As soon as I read your words on using more than 5g of starter it came back to me in a flash....I had forgotten....

My kitchen cupboard is covered with sticky notes.  My 'starter' log book sports several too...and then there are my binders where I have filed threads that I have printed out on so I can read them more easily than trying to read on my has 'flags' throughout....I have also resorted to sticking a sticky note or 2 to my body when things are really busy here....I should have invested money in sticky pads....

I trudge on...Today I am feeding my refrig. storage starters...something I have mastered.  I am thinking of simplifying and just sticking to them and forgetting about trying to do the counter is driving me nuts!

But I will go back to the 10g amount and give it another try...keeping temps more stable before I completely throw in the towel and take down my notes...


Mini Oven's picture
Mini Oven

And if you threw out all those sticky notes, you'd be surprised how much detail has stuck with you.  I grew up thinking one could never write on printed books or pages, but I got over it and put notes in my cookbooks and articles whenever I feel I don't want to forget a tweak or tip.  After all, they are mine to do with as I please.  

One of the main reasons for refrigerating a starter is to have some time for yourself and not feel like a slave to a feeding schedule.  If you bake often, or have a cold kitchen, keeping a starter out is economical.  The starter does fall into a schedule after a week and becomes predictable and easier to manage.

In cooler seasons, it is always good to warm up the starter when feeding either with warm water or a warm spot for the first hour or two and then move it to a cooler spot to slow down the feasting.  If the starter seems to be loosing vigor, with the next feed, give it longer warm feasting time.  (too vigorous, shorten the warm time) You can manipulate warm and cold to fit your baking schedule so that the starter is ready to go when you are.  Then all you have to do is remove what you need for your recipe, feed it and park it into a warm spot for the 1-2 hrs (or more) before moving it to the cooler spot.   Rye is pretty quick, wheat may take longer.  Seasonal changes will occur so when the temp rises in the kitchen, the warm feeding looses its importance.  

Even if you "throw in the towel"  it will not be in vain, for you have picked up some valuable information in doing all of this.  Sometimes it is also good to let your family see you return to a semi-normal state for a little while at least until you throw yourself into the next project.   :)




Janetcook's picture

A new day dawns and I am still hanging in with my starters.  Yesterday I settled on a proportion suggested by bwraith in an old thread on starters that was quite detailed and all my experiments were fed 10g starter:37g water:50g flour.

All are in glass containers so I can see what is happening.  All are 'behaving'.

They were kept by the fire and the temp in the room was about 74°.  Did start out cool - 60° but I did the warm water trick because I did remember that from somewhere... 

They all doubled and peaked before the 12 hour mark so I know they are okay. 

This morning I dropped the hydration level down to 70% to see if they will go 12 hours before needing to be fed again - that fits my schedule better...They were all fed 10:35:50. Shelf by the fire is 68° but the fire is just taking off and the temp. should be into the 70's within the hour.

The oven gets to about 80° with the light left on and that is just a bit too warm for me but I know I can use it as you suggest for the first couple of hours when the house is really cold....we are moving out of that season now and into our warmer weather.....I see green grass popping up in my lawn!

While doing all of this which was started by my starter smelling a bit off to me I realized that the starter I was using on my counter was a new starter that I had just gotten going...It was started using 'Carl's Sourdough Starter' that I sent away for in the mail....I realized that it is going to have a different aroma because it was 'grown' in another environment - different beasties all around.  Realize it will morph into what I had been using but it will take time....

Yes, I do seem to be learning something but there is so much ahead of me it is hard to see what I have gleaned....

My cook books look like yours....pages dog-eared....whole sections taped back in where the binding has given away....I can't bear to part with the old and buy a new because I would loose all of MY notes!!!

When I bake I have a baking sheet where I list all ingredients, times, temps and notes.  All is recorded and kept in my binders....never too old for a binder! They are like gold to me and I would be lost in my kitchen without them!  

I love all the colors available now in binders.  That way mine are color coded so I know which hold sourdough recipes or starter charts or commercial yeast recipes...just a glance and I can grab what I need quite easily...

Sometimes it is also good to let your family see you return to a semi-normal state for a little while at least until you throw yourself into the next project.   :)

I think I have passed the point of no return on this are teenagers and to them I will never be 'normal'....and, I am not sure I have ever been 'normal'  I mean who in their 'right' mind looses sleep over bread doughs...Who in their right mind gets excited about colorful binders to color code their baking recipes...the list could go on and on.....too late for me.  At least I am one who enjoys my insanity :-D