April 23, 2010 - 11:52pm
warmer fermentation = more sour flavour...?
I wonder if anyone else has had this experience. I like the sour flavour and want to maximize it. I've tried multiple long fermentations at lower temperatures and I have pretty universally been disappointed. The other day I ran out of bread altogether - eek! emergency! So I made the whole loaf in just a day, which is unusual for me. I did all my fermentations in an 85 - 90F environment. The bread came out more sour than when I had done 2 or 3 12 hour fermentations at lower temperatures.
Anyway, I was surprised by the results and I wonder if others have had similar experience.
:-Paul
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I think there are others who can give you a more cogent answer, but I"ll take a shot at it. What I've found searching online is applicable to the yeast and bacteria specifically related to San Francisco sourdough. That symbiosis has been studied extensively, probably because the baking industry is willing to fund the research. The results are also, according to some experts, good guidelines for other sourdough yeast/bacteria communities as well. Temperatures near 90°F favor bacteria growth, temperature near 82°F favor yeast development. However, yeast development falls off rapidly as the temperature approaches 90°F while bacteria growth continues to increase in the same range.
I think the myth (my word) that sourdough grows more sour at low temperatures is misinterpreting findings that bacteria that produce both acetic acid and lactic acid create more acetic acid at the lower temperatures. But the total acid produced is less at lower temperatures than at higher temperatures. given the same density and ratio of yeast and bacteria.
Of course, its not that simple because the yeast and bacteria populations are growing (or shrinking) depending on the temperature, and at different rates. Bacteria also experience a "lag time" each time you feed your starter.My head begins to hurt when I try to visualize that many dimensions; it approaches string theory ;-), but there is one erudite paper that, after many readings, I think I understand it a little bit--maybe.
http://aem.asm.org/cgi/reprint/64/7/2616
and here's another site that gives a more laymen's view, written by one of the author's of the above.
http://www.nyx.net/~dgreenw/whatistherelationshipbetwe.html
Neither of these address the lag time. I found a discussion of it in some other reference (lost to me now in cyberspace), I didn't save it because no practical numbers were given. I still don't know whether it's seconds, minutes, hours, or fortnights.
I don't know if this helps. If I were you, I'd just keep doing what works, and ignore the many myths (some terribly wrong) that seem to surround sourdough.
Now I've probably offended more than half of the TFLers who read this post.
David G
I've tried to create a more sour starter by building it at 90°F, for approximately sixteen hours. Subjectively, when it peaked it smelled decidedly tangier than the seed starter, And the bread had a noticeable tanginess, but it wasn't "in your face tangy" like some commercial San Francisco sourdough bread I've tasted.
I've never proofed a loaf at those high temperatures. I'm still working on my proofing box. Life's been interrupted by minor surgeries--stints in my leg arteries--I've had two catheterizations since we last exchanged postings, and I'm scheduled for a third (and last) next Friday. They've put a dent in my projects, because I have to baby myself for a while after each one.
Happy Baking, Paul
David G
Thanks for the info David. Good luck with your medical procedures, I hope it all goes well and that you heal quickly.
:-Paul
Save a two day old slice from your last sd loaf (you may have to freeze it to protect it) don't let it get too old before you use it either. Crumble it into your refreshed starter to use in the next loaf. Let the crumbs ferment with the sponge and see what it does to the sour flavor of your loaf.
Mini
Thanks Mini, that's very interesting. I used 50g of heel from the last loaf in this one. It added a toasted flavour to the whole loaf as well as some colour. It's certainly no less sour, perhaps a bit more, I'll keep playing with it. That's 50g of old bread added to 750g flour and 500 g water. I'm just starting another sponge now and using 80g of old bread. Any suggestions on amounts?
Thanks again,
:-Paul
I have used more crumbs than I thought a 100% hydr. starter could handle, doubling, tripling the visual amount, and still amazed all the crumbs got wet. The starter was looking more like dark paper mache and stiff but by the end of fermentation 12 or more hours later: softer, sour and lifted with bubbles throughout. One could make it wetter to speed up fermentation. I have let a rye starter like this ferment for 24 hours without any problems. Had even tucked it into the fridge for another day! The last loaf I made in Korea went that route. My husband wanted a bread crash coarse so I put the starter into the fridge for another day until he could mix up the dough. Very rich sour!
I'm cranking out my first loaf today. A 50% rye with spelt and cooked carmelized spelt berries. The old bread is a sunflower rye. Old bread with rye is the best, the more rye the better or am I just partial?
Mini
That's some great encouragement for experimentation. I've been pretty timid I see. I did add a little extra water to the sponge this evening. I like leaving it out on the deck overnight - to sort of tune in to the local temperature and also to slowly change temperature down and up. As long as the low is above freezing, and it's quite mild here now.
"last loaf in Korea"..."cranking out my first loaf today" you've moved?
:-Paul
Paul:
Like you, I prefer tangier loaves. Usually, I can accomplish a very tangy loaf by using a firm, 50% hydration starter and cooler fermentation. However, fermentation took place under high temperature (from 86F - 96F) usually did not produce tangy loaves for me. That's why I've been using high temperature fermentation in conjunction with a 100% hydration starter to produce loaves with very mild, subtle tanginess that my husband prefers.
Yippee
Thanks Yippee,
That's what I thought was generally agreed; longer, cooler fermentation resulting in more sour flavour. Since I got the opposite result I was wondering if anyone else did as well.
:-Paul