The Fresh Loaf

A Community of Amateur Bakers and Artisan Bread Enthusiasts.

Acetone Starter Odor

JayDubs's picture
JayDubs

Acetone Starter Odor

I've read previous posts by people with the same problem, but mine has a unique twist:

My 100% hydration starter was thriving in a one-pint, wide-mouth mason jar covered with a paper towel and rubberband (once/day feeding, 1:2:2 starter:water:flour, using 50/50 whole wheat and rye flour), but it regularly got a hard brown skin that I thought might be inhibiting its ability to "breathe" and rise fully. After reading a bunch of recommendations for keeping the moisture up, I ended up getting a 3/4 L Bormioli Rocco Fido canning jar and keeping it with the lid down, rubber gasket removed, unlatched.

The first day the starter lived in its new home (which I washed ahead of its first use), it developed a strong nail polish-remover smell. I transferred it back to the ol' mason jar after its next feeding -- into which I added 5mL of lemon juice, per past forum posts -- and the starter went back to its usual bready odor.

Out of curiosity, I put it back in the Fido jar, and it smelled like acetone again the next day. Then I put it back in the mason jar with a paper towel lid, and it was back to normal a day later.

The easy solution is obvious: keep using the mason jar and paper towel lid, and deal with the crustiness. But does anybody have an explanation for what might be going on here? Is anyone else's starter this sensitive to its container?

drogon's picture
drogon

acetone smell means its hungry, so feed it more.

I don't move containers though so not much use there, but since day 1 I've been using 1 litre kilner jars WITH the rubber seal and with the lids latched closed. My starters live in the fridge and are used 5 days a week. I don't top-up/refresh when I don't use them. They've yet to explode - thee jars are designed to keep gas out (hot filling with pickles, etc.) not in. I do get a "psssht" of gas escaping when I open them, but I've also found the rye all over the fridge in the past when it got a bit too active...

-Gordon

JayDubs's picture
JayDubs

Thanks for the advice!

Interestingly, my starter develops the smell before it's risen to its highest point. I feed in the morning, come home from work around 6, notice an acetone smell but an active starter that continues to rise another quarter inch or so before falling slightly overnight. This suggests to me that it takes on the odor before it gets hungry, right?

Tangentially: I'd always assumed the rubber gasket was removed not only to let CO2 escape, but also to let O2 in. You're saying the starter doesn't need to "inhale," only to "exhale?"

drogon's picture
drogon

I've rarely had the acetone smell - until recently that is when I've started to feed my spelt starter with my home milled and sifted flour. I just give it a stir and use it (directly from the fridge most times)

As for gas - give yeast oxygen and you get more yeast, remove the O2 and it starts to digest sugars into CO2 and alcohol... I give my starter jars a good stir when I top them up, but that's more to mix the flour & water than anything else, otherwise haven't really thought about it...

However I am also working with a local microbrewery and they are much more concerned about it when they make their yeasts up - they spend a day or 2 making yeast with lots of air being bubbled through the mix to make more yeastys before it gets pitched into the wort - even then, they aerate the word once it's cooled out of the boiler before pitching the yeast..

The only remotely similar thing I've seen in the bread world is Richard Bertinet talking about adding air to the dough with the French slap and fold method of kneading. That's too much like hard work for me and anyway, I don't want more yeast, I was the gas!

-Gordon