November 2, 2014 - 7:10am
I'm sure it's been done before but ...
... if it has I'm having a bit of a hard time finding it.
Has somebody ever posted a concise, easy to follow "smell guide" for starters? Something that explains, in terms that are easy to understand by somebody without much of a background in organic chemistry, what is happening when a starter smells a certain way, which smells are indicative of a problem and how to address those?
Cheers.....
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Here's one thread:
http://www.thefreshloaf.com/node/28754/does-sourdough-starter-always-smell-so-bad, but it's a bit scattered.
Here's my take on sourdough starter smells:
No aroma, just smells like raw dough: starter is probably too young to use. Solution: wait longer to let your starter mature.
Dirty sweat-socks, vomit, light banana smell, stinky cheese, Parmesan cheese, blue cheese, rotting fish/meat, rotten/spoiled milk, musty/moldy: starter is going thru a transitional period with some nasty bacteria like leuconostoc competing with the lactobacilli, or is otherwise unhealthy. Solution: either feed with pineapple juice or other acid fruit juice (a la Debra Wink) to speed up acidification of the environment, or wait to see if the stage will pass thru more regular feeding.
Alcohol, Acetone, Paint thinner, Nail polish, heavy/overripe banana smell: underfed, but generally active & probably healthy. Solution: feed it more and/or feed it more often.
Vinegar: it's a toss up. Could be healthy but more acetic acid due to feeding technique/firmness/flour/storage, if you like a more San Francisco style sour sourdough. Or, if vinegar is more like "dirty sweat socks" could be unhealthy. Solutions: change feed frequency/firmness/temperature/flour to reduce acetic acid OR feed temporarily with acidic liquid (such as pineapple juice a la Debra Wink.)
Sweet, yeasty, ripe fruit, champagne, pleasantly beer-y, generally pleasant: starter is healthy and likely ready to use.
NOTE: if your starter is a fruit yeast water starter, all bets are off. Aromas will be heavily influenced by fruit you use to feed it. Generally should smell yeasty, champagne, sparkly, and taste sparkly and somewhat dry/tart/sour.
Thank you! My starter has never seen anything other than flour. I started out with organic rye flour but these days I use white wheat flour as it's a bit more versatile for how I use it (I make white bread sometimes, and light brown bread at other times. I do make the occasional rye bread but I'm happy to build up the rye starter in three steps from a small amount of my usual starter).
I'm not entirely sure what acetone would smell like. How would you describe it? When I forget to feed, sometimes, I do get an unusual smell alright, not really vinegary, certainly not "dirty sweat socks" or anything like that, but kind of mildly "chemical". Not as strong as "nail polish", though.... That's when I get a bit worried.
That could be the chemical smell you're detecting.
Acetone smells like...acetone :) which is the primary ingredient in many nail polish removers. Some people say acetone/nail polish remover smells like very ripe bananas, and they're kinda right: in fact bananas produce a type of ethyl acetate as they ripen.
If you want to know what it smells like, let a banana ripen until it's basically black, and/or buy a bottle of acetone-based nail polish remover (it's cheap). Otherwise a bit hard to explain, kinda like trying to explain what an orange tastes like :)
Maybe my nose is different, but I never perceive these odors others describe. Even after sitting in fridge for months I never smell dirty socks. Mine goes through a nutty stage, then a fruity, then vinegary stage. The nutty is the first key the starter is getting usable.
I know, I can't say I've ever smelled dirty socks myself. Interesting, dirty socks smell is a combination of ammonia, isovaleric acid and lactic acid.
I have experienced the putrid/vomit stage on several starters I've built. The ones that have been worst are the whole wheat starters that were created at very warm temps. The organic grape starter I built years ago a la Nancy Silverton had a distinctive sharp-cheese quality at an early stage, which went away as the starter aged.
Usually these strange odors arise when making a new starter. I think using whole-grain flours tends to make smellier mixtures. The absolute worst I smelled was from rye starters I made at 77 F. Not expecting anything particularly unpleasant, I took a deep whiff of one the first time I checked on it and nearly gagged. After a few days of feeding at normal room temperature, the smell fortunately went away.
The only other memorable smell I've encountered is the acetone/paint-thinner one. I don't think this was due to underfeeding because the smell remained even after several very generous feedings.
So ... did you chuck out your starter then?
I already had a starter, which is the one I still use today. I was making the new starters just as experiments, so I did end up throwing them out. Supposedly, you can salvage the ones that smell like acetone with continued feeding, but I didn't have the patience for it at the time.
What I've always wanted is an odor key for established starters, not new ones. There is a wide range in which starters can work, producing different characteristics. In 70s and 80s room temperature, when I use the float test (with liquid starters, obviously) I find there is very little soul to the bread, although rising is fine. ("Soul" meaning I want to keep eating!). If a liquid starter smells buttery/nutty (which is the next stage, and I've attributed to lactic acid) the flavor is much better. This stage seems quite narrow, maybe half an hour to an hour. Then the smell starts to get gradually more vinegary. That can work too, depending on the bread. ( At that point the dough strength/runniness seems a more significant marker than odor.) Stiff starters have similar odors, just less pronounced. And whole wheat and rye are different too. After more than a decade baking I still don't have a good handle on this.
Very good questions. I like your "nutty" or "buttery" descriptors. I've experienced "nutty" but not "buttery" in ripe starters.
Descriptors are such a funny thing...people perceive smells in wildly different ways, not only at different sensitivities, and context is everything. I remember sitting in a wine tasting class a few years ago with a bunch of wine professionals and hearing "plastic bandage", "iodine", "can of creamed corn" as wine descriptors. Then again, some things might smell exotic to others. If you've never smelled "lychee" it's hard to describe what that means.
My starter is 14 months old now. I think I can call it "established" alright. Most of the time it's well behaved but it has the occasional "temper tantrum" ... Sometimes I know I've been negligent, and I forgot to feed it one day. Other days I'm not so sure.