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Acetone smell in starter

rjstucker's picture
rjstucker

Acetone smell in starter

It seems my newest starter, the one I just baked my first loaf with yesterday, might be going bad again. :( I kept it on the counter and fed it regularly, just after starting to fall, for 3 weeks, in order to make sure it was good and strong before refrigerating. I put it in the frig for 3 days, took it out, fed it twice, then fed again after taking out what I needed for baking yesterday. Since there was very little sour taste to that loaf I decided to keep it out and change the refreshment ratio to 1:1. I fed it last night, and this morning, within half an hour of it starting to fall went to feed it again and it smells to me as though it is starting to take on an odor of acetone, the same thing that ruined my last starter. I went ahead and fed it again, keeping only 1oz, and included 0.10oz of lemon juice, which was recommended in several comments to a post I found here on The Fresh Loaf.

So, three questions: 1) What is the best way to keep this from happening; 2) Though I know the processes going on in the starter are anaerobic, is it possible that keeping the jar sealed, which would change the pressure within the jar, have something to do with it? Previously I had covered it with plastic wrap with small holes punched in it; 3) Should a starter fed at a 1:2 ratio have a sour smell to it? That is the ratio at which I was previously keeping it, and after 4 days of refreshments the aroma changed from a wheaty, fruity smell to sour.

Ford's picture
Ford

Don't worry, just keep your regular refreshment schedule.  I feed my starter in the ratio of 1:1:1 by weight.  The acetone odor will go away when you bake with the starter.

I store my starter in the refrigerator and refresh it on a biweekly schedule, if I am not using it before.  The day before I bake I refresh the starter, and then that evening I refresh again, both times at the 1:1:1 ratio by weight.  The next morning my starter is ready to go and very active.

Ford

richkaimd's picture
richkaimd

I use sourdough starter only as a carrier of the leavening agent (yeast), not as a carrier of taste.  Thus, I generally use very little of it.  I get my sour taste, more or less of it, by varying the duration and temperature of the bulk rise.  Thus, for example, I can use my sourdough starter as the leavening agent for challah and, because I put it in a warm place for the bulk rise, get absolutely no sour flavor.  I use my starter to make a Tartine-style loaf and allow that to rise sometimes at 60 degrees.  That loaf is pretty sour.  When I make a sourdough starter leavened Pain a L'ancienne from Reinhart's Bread Baker's Apprentice I do a bulk rise at 40 degrees for up to 18 hours in my fridge.  That loaf's pretty at that point.  Note that I use only about half a cup of starter in all three recipes and get different levels of sourness by varying the temperature and duration of the bulk rise.

drogon's picture
drogon

and cool it down a bit, if possible. It's just a bit hungry. Dump in more flour & water and personally I'd forget about anything else. I store mine in the fridge and take them out, use a portion to make up a more active starter which I use to make bread with. the mother then gets fed and put back in the fridge. I do this 6-days week. Works well for me. Mine are kept in kilner jars with sealed lid. If I were keeping them at room temperature, I may consider removing the rubber gasket though, but plenty of places will post live starter to you in the same type of jar (but smaller) without any issues.

-Gordon

prettedda's picture
prettedda

I agree with the others - just feed it regularly (twice a day) at regular temps (60 to 80) and it should do fine. As to the ratios, seems everyone has their own system. I use a lot less of the old starter than some of the suggested ratios. My feeding is 5 grams of old starter to 40 grams  water plus 20 grams whole wheat plus 20 grams all purpose. If it's a little funky using less of the old starter might work better. It is hard to kill them off. As I said unless there are molds feeding regularly for a few days should bring it around. 

Big Ben's picture
Big Ben

i don't know if acetone is what is am smelling, but I find the best results when I switch my starter to a new container every few weeks. After a few weeks I see dry brown on the top of my container and the smell is not as pleasant. 

drogon's picture
drogon

old fashioned pear drops (probably a UK speciality), or nail varnish remover.

 

-Gordon