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Could my starter be contaminated?

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Janknitz's picture

Could my starter be contaminated?

I had a lovely starter, but I decided a to make a bread that took probably too much of it this past weekend, leaving me only about 12 grams.  To add insult to injury, I'd transferred it into another container so that i could clean its crock.  So the old, dried starter that clings to the side of the crock was not there to help. 

I added 20 grams each of flour and water immediately  and let it sit for most of the warm evening.  Then I added an additional 50 grams each of flour and water (without discarding), and refrigerated as usual.

It just doesn't smell good anymore--more like gym socks than the clean, sour smell it used to have.  I decided last night to take it out and feed it twice daily on the counter for a while--sort of sourdough starter ICU. 

This evening, though, there is an unusual amount of bubbly activity--almost a foam of bubbles on the surface instead of the big, heavy bubbles that usually sit in the starter (there are those, too).  Is this a sign that some bad baccili have gotten a stronghold? 

Is there a way to restore the balance--perhaps by acidifying the environment with some pineappple juice?

I do have both frozen and dried samples of the starter when it was going well.  Would it help to add some to the current starter, or should I consider (if I can get the dried starter revived) to just start over?

Boo Hoo--I was so happy with my "Baby Bobby". 

Janknitz's picture

I just fed the starter for the night, and besides being very bubbly  it was very liquid-like.  Instead of marshmallow-like gluten strands, it was all liquid like pancake batter and it did not stick to my spoon as usual.  It's a 100% hydration starter, and usually it's thinner when its feeding time, but not THIS thin.

On the plus side, it did smell better after I fed it. 

I realized how it must have come to be contaminated (if that's what the problem is).  I bake all weekend, so I keep a metal bowl on the counter with "bench flour".  When I fed the starter this morning, there was still just enough flour in the bowl to feed the starter, so I used it.  I think that was a BIG mistake!  This is flour that has been sitting out exposed to the air (windows open, and the  occasional misquito flying around) for about 3 or 4 days.  I wouldn't be surprised if there were nasty critters in there (of the bacterial species). 

So my question still stands--can this starter be saved, or am I better off to revive some of its frozen or dried progenitor? 

Jw's picture

I second that opinion: just keep feeding, it should be fine. I have frozen (ice-cubed) my starter before a holiday and was able to revive it. Rely on the smell.

In my opinion, if the smell is not sour, and you see no bubbles, you are underfeeding. Start with 2x daily feeds for a few days.... I was able to revive my starter..


SourdoLady's picture

I'll bet it will be fine after a few good feedings. I had a starter that acted the same way recently and it took a couple of days of babying but it came back to its old self. The thin consistency is, I think, because the starter has gotten very acidic and it just destroys all the gluten. Don't give up on Bobby just yet!

Janknitz's picture

Thanks--that's good news and gives me hope. 

I'll keep feeding it and see what happens.  I'm hoping to be able to bake with it Thursday night to make another KAF mild sourdough loaf, BUT this time I'll make sure to feed it up so that there is plenty left in the crock!

Other than baking with it, is there any way to "prove" sourdough to make sure it still has leavening power?  Because of my work schedule, I can't afford for it to fail on Thursday night because I promised to bring home made bread to an after-work gathering on Friday. 

I suppose I could make another (non-sourdough) bread Wednesday night and freeze it for insurance.  Oh darn, I'll have to bake another loaf (I love it!). 

Just Loafin's picture
Just Loafin

When you're going to use a large amount of starter, it's best to clone yours in a seperate container with as much as you intend to use, or what most do, feed your starter more than you usually do. You'd want to feed it enough to cover what you will need, plus what you usually carry over to a new feeding. Both accomplish the same thing, and being a 100% hydration starter, both are extremely simple to do.

Having a small amount (12 g) of inoculate shouldn't be a problem, but it will take longer to double/triple. Anywhere from 8-12 hours. I've never heard of contamination from bench flour, but I guess you never know... one thing that is known is that a robust starter can defend itself just fine, so you shouldn't need to start from frozen. The way you 'prove' your starter is by feeding it and seeing how long it takes to do its usual business and its usual volume. You already know that smell and color are strong indicators as well, and should be normal before baking with.

Take 26 g of water and add 10 g of your starter to it. Whisk air into it briskly. Add 40 g of flour and combine with a fork until a fairly stiff dough forms. Lightly knead the little ball of dough (slightly larger than a golf ball), add pinches of flour if it's too sticky. Once it's holding a ball shape well, place in a small bowl and lightly cover with plastic wrap or whatever. It should triple or quadruple in about 8-10 hours. If it does, then your yeast is in good enough shape. There's no way to test (that I know of) for the proper acid balance (sour taste) other than baking with it.

Best of luck! Just be patient!

- Keith

Janknitz's picture

I'll try to make a little ball tonight and see if it it will grow. 

This morning it had a little more gluten structure than last night, but still lots of foamy little bubbles in addition to the usual big ones.  I might have let it go too long between feedings and the weather was warm--maybe that's why it got so runny. 

I know that Susan of Wild Yeast says that somethimes you have to increase the frequency of feeding if the kitchen is warm, but I'm away at work when that would need to happen. 

It is gradually smelling better, but the flavor is not like it was when I taste it. 

Janknitz's picture

I THINK what's happening is this starter is really taking off, perhaps for the first time.  Our kitchen is warmer than it has been in the months since I propogated the starter, though by no means hot. Our kitchen is running in the high 70's--it had been only in the mid-60's up until last week.  We are having a slow and mild start to summer (which will probably end in a hot and miserable early fall).

Anyway, I decided to do a test run of the bread I'm making tomorrow night for our Friday evening social (KAF's rustic sourdough) to see how it came out. 

YOWSA!  This rose a lot compared to the same loaf I made over the weekend, and the dough was a bit stiffer (surprising, since the starter seems thinner) and easier to work with (I used bread flour this time, too).  The oven spring was incredible, and it smells great.  I'm looking forward to cutting into it to check the crumb and taste it--probably tomorrow morning.  (I'll post pics after I can photograph the crumb).  

There is yeast in this recipe in addition to starter, so I can't attribute all of the leavening to the starter, but clearly whatever condition Baby Bobby is in did not HURT the leavening at all.  

Meanwhile, my usual feed (60 g each of flour and water) of Baby Bobby is not only more bubbly than usual, but is rising much higher in the crock than usual.  

Baby Bobby seems to have entered adolescence (so THAT explains the gym socks smell!).  Next thing you know, he'll be asking me to call him "Bob" and want to borrow the car!