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KAF starter going acetone

paul0130's picture
paul0130

KAF starter going acetone

I ordered King Arthur’s starter about a year ago, and it has been consistently great with very little maintenance. Survives long stretches in the fridge, etc. The last time I had it out the fridge about a month ago, I think something bad got in there because I noticed the acetone smell. I was a little concerned when I took it out a few days ago because there was no hooch. Also, there was barely any activity after feeding it. But sure enough, by second feeding it was going crazy again, but that smell came back.
I’ve been feeding it 1:5:5 ratio twice a day. Then I tried 1:8:8, and this morning 1:10:10. Still have that smell. It has no problem doubling in size, so I guess the yeast is healthy.
I did manage to get the smell to go away once by keeping it at about 90 degrees for the evening in the oven. Next morning it smelled pretty good, but the acetone came back after that.
I have read several articles on acetone, but it seems the solution can vary depending on situation. Not sure if I should go with the salt method, or lemon juice, or something else for this particular case, but I’m hoping I offered enough data that the experts can figure it out :) . Thanks!

Mini Oven's picture
Mini Oven

:)  Rye?  wheat?  combo?

http://www.thefreshloaf.com/comment/239621#comment-239621

You need to lower the pH in the starter to combat the particular bacteria making the acetone aroma.  The rise is most likely bacterial as you said you fed 1:10:10 and the rise only doubled.  Could be that the starter is to thin to rise further but I would expect more rise from yeast.

Are you letting the fed starter peak in activity and then decline before feeding again?  This gives the starter the chance to increase acids and defend itself better.  Heat helps the bacteria population and increase acid in the starter, perhaps why the 90°F rise helped.  Try the lemon juice in your starter.  While your are at it, start a new starter now, just in case, without the stress and let it take it's time maturing while you use the lemon juice starter.  Keep them separated and don't mix spoons, jars or covers.

paul0130's picture
paul0130

I'll go ahead and start another starter with the lemon juice today. I built up a cup of starter last night, just leaving in the 90 degree oven (which cooled to 70 overnight) and it smells pretty good this morning. It has a nice fruity smell. I'm assuming this is OK to bake with? I'm going to start the sponge here shortly. I had my regular starter on the counter which actually smells not too bad this morning, but still a hint of acetone. I read a rather discouraging article which claims acetone smell is irreversible, and once it's in there, it can be controlled, but can come back quickly if not well maintained:

http://www.sourdoughhome.com/index.php?content=revivingastarter

I suppose that means that bad bacteria is in there, and can be dominated for a while, but if my feedings aren't correct they will come back? Something like that?

BTW, thanks for the reply Mini. You helped me out with my Myrtle Beach "Sandlapper" starter a while back. That one is still going strong, but doesn't have the same rising power my 200 year old KAF starter has. It does have a more sour flavor however... but that's a different thread :)

Mini Oven's picture
Mini Oven

out of my head... "We are good Sandlappers...."  

Well you know what you have to do to make it stronger.... feed often and always to peak.  Cranbo has a nice formula for boosting.  Saw it a few days ago.  We're having fun in Bali with it right now.  doing a few 1:1:1 AP feeds every 4 hours in warm weather, then a long overnight feeding with lots of flour.  Kicking  those ol slowpoke yeasties in their micro organismic butts we are.  :)

Does your KAF starter have a name?   it might be a pure starter and not a wild one.  Meaning a specific one.  I remember a lot of beating air into the mixture and waiting for the bacteria to clear the starter of the offending organism.  I think once they are completely wiped out, they are out of the starter.   The trick is getting them all and preventing them from coming back.

You might want to send a private note to Mariana and see if she knows something that would help.

paul0130's picture
paul0130

I'll have to find Cranbo's formula and give that a try with the Sandlapper. My KAF starter has no name... maybe that's bad luck :) I usually just call it "my good ol' KAF starter". What about the lower hydration trick? I keep a 100%. What if I tried 75% for a while see what happens? Would that help balance things out? I just checked it again and that dang smell is coming back. BTW, I'm assuming this is OK to cook with right? I have the sponge going right now. Also, I always just use KAF AP flour with my starters.

 

 

Mini Oven's picture
Mini Oven

flavour by dropping some in a hot pan for a tiny pancake, see if the taste is there.

cranbo's picture
cranbo

here was my post about boosting a starter:

http://www.thefreshloaf.com/comment/316257#comment-316257 

paul0130's picture
paul0130

Perfect! Thanks, I'm definitely going to try this.

Ford's picture
Ford

Just to emphasize Mini Oven's response.  I think you might be overfeeding.  The weight ratio of 1:1:1 works for me in my refreshing routine, with 8 to 12 hours for fermentation before refreshing again at room temperature, about 75°F.  I store my starter in the refrigerator for up to 3 weeks between baking and do two refreshments at room temperature before I make my dough and bake.

Ford

paul0130's picture
paul0130

Oh well, I cooked with it anyway and it was awful. The bread had almost a metallic taste to it. I ended up throwing it out. Also, I was having issues with bottom heat on a previous loaf and moved the grate to the bottom level. Unfortunately, I also added a large baking sheet with water in it at the bottom of the oven. This make for a pretty loaf, but the bottom was under cooked. Anyway... just for the heck of it, I changed the starter to a 75% hydration and made just enough to cover the bottom of the mason jar. The next day it grew to about a 1/4 of the jar, smelling like acetone. What ever is in there, is crazy! I just switched it to a smaller jar and added a few drops of lemon juice and went back to 100%. I'll see what happens from here. BTW, I remembered when this all started. My wife used the wooden (bamboo) spoon I normally use for spaghetti sauce. I tried cleaning it as well as I could, but couldn't get that spaghetti sauce smell out of there. Right after I used that spoon is when this acetone smell first started!

Mini Oven's picture
Mini Oven

the starter, keeping it out.  Try not feeding it for a few days. let if ferment like crazy.  I suspect what you think is yeast is bacterial growth.  How big is the starter, you might need more lemon juice? You might want to try beating lots of air into the starter, with one mixer beater for several minutes.  Could back up to 100% hydration too.  

I don't think the spaghetti spoon did anything.  That's just grasping at straws.  :) 

doughooker's picture
doughooker

I remembered when this all started. My wife used the wooden (bamboo) spoon I normally use for spaghetti sauce. I tried cleaning it as well as I could, but couldn't get that spaghetti sauce smell out of there. Right after I used that spoon is when this acetone smell first started!

Do you think a little spaghetti sauce crept into your starter?

You're working too hard trying to salvage what may be a lost cause. Forget monkeying around with lemon juice. Just begin a new starter.

paul0130's picture
paul0130

I think at this point I'm in it for the challenge and the learning experience. I put a few drops of lemon juice yesterday and that definitely calmed activity. I think Mini is right, that it's the bacteria causing the activity and not the yeast. Also went back to 100% hydration and 1:1:1 ratio. Did another refresh this morning with a little lemon juice again and I think I will try Mini's suggestion and leave it until Thursday morning to see what happens. Again at 100%, 1:1:1. But I also busted out the old Sandlapper to try and strengthen that one up a little. Trying a sourdough cornbread recipe for a chili contest Friday which I am hoping will push me over the edge toward victory :)

doughooker's picture
doughooker

Lowering the pH with citrus juice suppresses leuconostoc activity in the early stages of a starter, but that's not the case here. You don't know what's causing this acetone odor; you just have a couple of people guessing at it, and they're not even educated guesses.

There's no law against spinning your wheels.

Mini Oven's picture
Mini Oven

This acetone aroma is a tricky thing especially for a non-chemist like myself.  But I have enough understanding to know that there are different causes for acetone like aromas.  Many involve the fermenting of sugars and alcohol.   

Either underfeeding or overfeeding might have caused it and perhaps one or the other or a stable schedule may correct it.  Every time flour is added to water, there is a tiny chance for these bacteria to be growing but with the addition of a sourdough culture, soon overtaken by the starter and put in line or killed off by a rise in acidity.  There exists such a large variety of bacteria and yeast growing in a wild starter it is hard to know the exact cause and if it can be corrected.  One can try several ideas, split up the starter and feed with different amounts at different temps and pH additives or flours and see what works with time & patience and/or simply start up another starter at the same time while playing.  

You do acquire experience with this playing around and hopefully it makes it easier to start and maintain a new starter.   If every starter you start, ends up on this track of bread not only smelling but tasting of acetone, time to look seriously at the way the starter is maintained.   

 

paul0130's picture
paul0130

My Myrtle Beach starter was coming along so nicely I gave up on the KAF starter. The lemon juice seemed to be doing the trick, but maintaining two starters was getting chaotic. Especially after building up the MB starter, it rises like crazy now and smells great! I made two backups and put them in the freeze. One from before the buildup and one from after. It does get a mild, nose burning, acidic smell after a feeding, but besides that it looks pretty good! Experimented with using my pizza stone tonight since the pan of water at the bottom of the oven was affecting the bottom heat. I also got a couple of proofing baskets a few weeks ago, so after they rose, I just plopped it onto the pizza peel and slid it onto the stone. Bottom heat was still not quite enough, but better. They didn't come out too bad, and tasty! Pic below. I need to devise a different method for using water in the oven.

Mini Oven's picture
Mini Oven

can be pungent!   Good looking loaves!   

Right now I have a very old narrow steel loaf pan that sits on the right side, on the bottom of my oven when I'm not using a roaster, clay mould w/ lid, or two woks, or two saucepans.  I put a double layer foil tent over loaf pans.  Have you tried using terra cotta plant pots as covers for breads on stones?  A bolt and a couple of washers in the drainage hole plugs it up and makes a handle.  

paul0130's picture
paul0130

I've never tried that, but sounds like something to try. So if you use a cover, do you not use water? Also, do you adjust bake time and temperature? I did a "no knead" in my cast iron dutch oven once (high hydration), will that work too? While the boules are good looking, I'm thinking about switching to a batard so they are easier to cut. I get nervous when my teens go to cut :) Maybe loaf pans would be best too!

Mini Oven's picture
Mini Oven

I set a pan of water in the oven. Not too much, to preheat with the oven.  I use a variety of ways to get steam.  Every oven needs some experimenting to find the right set up for different breads.   Breads with high hydration will provide their own steam.  The trick is to keep the skin of the dough soft while oven springing in the first 8 to 15 minutes of most bakes.  Then remove the steam (or not add more) so the dough surface can dry/set and heat up to brown.  Too much steam will prevent browning and not enough will cause some splitting around the lower shoulders of the loaf.  Many covers do leak a little so the danger of over steaming isn't a problem.  A pan of water on the other hand can often contain too much water and must be removed if it hasn't gone dry after the initial oven spring.  Depending on how long the covers take to transmit heat to the dough, there will be some added baking time.

I have a dutch oven too, I could flip that over onto a stone (if I had one) to trap in steam.  I often spray cold coverings (do not mist hot glass, ceramics, danger of explosion) with a mister before setting it in place over a loaf.  Go thru the motions cold, with the oven mitts on so you know how to lift it off the hot stone when you need to.  Adding needed handles is always worth the effort.   Slipping a putty knife blade under a rim is also doable.  But if the whole pot proves awkward and slippery cold, it can be nasty when hot.

About those knives, time to teach the kids how to use them and keep them sharp before they cut themselves.  All the safety precautions and handling.  (How to carry and how to walk with a knife, how to lay one down and how to wash and store them.  Respect for dangerous pointy objects.  

Shapes of the loaf are up to you.  I just picked up a large oval grass basket, a good banneton for a 2kg+  loaf.   My clay baker can fit inside it!  I might end up using an up-ended (misted) roaster pan over a baking sheet for that monster loaf!  :)