Can I stretch my yeast supply with a levain?
Hi all,
I am lucky enough to have a bag of active dry yeast in the fridge, but I'd like to keep a yeast pre-ferment along with my sourdough pre-ferment in order to make my supply last longer. I imagine after long enough and multiple feedings it will start to turn into a sourdough. That's ok, I'll just add it to my sourdough and start another batch. Is there a write-up I can look at somewhere, or does anyone have any tips? Here is my basic idea. Please let me know if you think this will work, or point me to any instructions you know about. Thank you!
Basic idea:
Combine 2 or 3 grams of active dry yeast with 300 grams of fresh-milled whole wheat flour and 290 grams of lukewarm water. Leave at room temperature until double. Stir down and place in the fridge.
On baking day, take out of the fridge. Use 150 grams or so as leavening for my bake, and feed mother levain with 100 grams flour, 95 grams of water. Let mother levain double in size before stirring down and placing in fridge.
I should add that I bake bread about every 2 to 3 days, using 100% fresh-milled whole wheat, and the above is an outline of my current sourdough starter maintenance regimen. I feed the sourdough with whatever I'm using in the bread, since bugs got into my rye and I had to throw it out.
It takes 100 to 150 grams of my sourdough starter, straight from the fridge, to raise a 550-grams-of-flour dough in around 6 to 8 hours (for the first bulk proof.) I'm not making sourdough every time, so the starter comes out and gets used and fed about 3 times a week.
What do you guys think? Can I just make a little yeasted dough ferment and treat it like sourdough?
That is pretty much exactly what I have been doing for roughly two weeks, now. So far, so good (whew!) it seems to be working. Best wishes, on yours!
I hope it stays alive and rising for you!
short answer: No.
You're conflating commcercial yeast with wild yeast. They are different animals.
Wild yeast can be maintained in a symbiotic relationship with lactic acid bacteria. The acid from the LAB keeps other bacteria at bay. They live happily together in a wet flour (batter/dough) environment when properly fed and refreshed, based on storage temperature.
Commercial yeast does not, cannot, have that "ongoing relationship" that allows _indefinite_ existance after being activated. If it did we wouldn't have to go through all the hassle, and two weeks, of creating starters from scratch, coaxing wild yeast and LAB to bloom.
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If you make a "levain", or pre-ferment, with commercial yeast, to multiply it, there is nothing wrong with that -- cookbooks have plenty of those formulas.
BUT.... the "CLOCK" starts, and you better use that batter/dough within a certain time frame (several days, refrigerated, according to Hertzberg/Francois) or it will spoil.
If it does "just happen" to regenerate/continue on (and in a healthy manner), then it is only because naturally ocurring LAB and wild yeast from the flour have taken it over, and then you have a _sourdough_ starter.
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The best way to conserve/preserve _commercial_ yeast is to leave it in its dry state, fridge or freezer, and use pre-ferments (levain, etc.), or long-rise straight doughs that multiply its efectiveness. That's what I do, I use only 1/4 tsp commercial yeast per loaf, not the standard 2-1/4 tsp or 7 grams, when I make a commercially yeasted loaf.
BUT... that pre-ferment is not "immortal" like sourdough. It lacks the LAB, and commercial yeast does not (cannot) enter into the long term symbiotic relationship with LAB that wild yeasts do.
(When I say "indefinite" and "immortal", I don't mean the individual cells live forever. Rather, they reproduce and eventually die off, and the "circle of life" continues.)
(I invite mwilson and Debra W. to please weigh in.)
Thanks for your informative comments, Idaveindy.
It occurs to me that there are lots of instructions around on how to preserve sourdough (mostly by drying, if I remember correctly.) I wonder if we could propagate and then preserve yeast by drying a pre-ferment and keeping it in the fridge, then treating it as if it were cake yeast. Have you heard the stories of people who take a ziplock baggie of desiccated sourdough starter with them when they travel?
Here are the King Arthur Flour instructions on drying sourdough starter to preserve it.
https://www.kingarthurflour.com/blog/2015/05/01/putting-sourdough-starter-hold
"I wonder if we could propagate and then preserve yeast by drying a pre-ferment and keeping it in the fridge, then treating it as if it were cake yeast."
Without LAB, there's still a countdown clock on it. Fresh/cake yeast is dated, and when you open it, then a shorter countdown clock starts.
A lot of packaged-refrigerated food behaves like that. The expire date might be (for example) 30 days in the future, at the time you buy it. But once opened, you have to use it up in 5 to 7 days.
I think fresh/cake yeast is like that.
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Re: drying out sourdough for storage. Yes. I do that. But sourdough (wild yeast and LAB) is a different animal, or system, than commercial yeast.
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Come to think of it, the yeast makers likely chose their particular strain of yeast so it could not be maintained indefinitely in the home. They want repeat sales.
If commercial yeast strains could be kept indefinitely by home bakers, I'm sure some ingenious bakers would have figured it out.
Who knows? YOU might be that ingenious baker who finally figures it out!
I've raised two breads with my poolish so far, and given it two refreshments. It seems to be working fine and keeping fine, but I think I'm going to switch to a yeast water for my non-sour leavening culture so I don't have to keep two flour-based ferments going. I'd forgotten about the option of yeast water as a substitute for commercial yeast. If I remember correctly it was pretty easy to get it going.