Do yeast cells reproduce in a starter or dough?
Hi all, this is my first post on TFL.
First of all, I have, with great pleasure, been reading TFL for many years and I have read multi-hundreds of forum posts about sourdough and I'm grateful with all the things I have learned by reading those posts. I especially do appreciated the messages of Debra Wink.
But there is one thing I never came across (but maybe I missed it): the answer on the question "do yeast cells multiply after refreshing the starter (or mixing a starter part in a dough)?"
And because I never seen this answer, I still can't really grasp the science behind refreshing a starter many times to make it active enough to use it for a dough to make sourdough bread.
I'm especially interested what happens to the number of yeast cells after every refreshment of a starter. I already understand about the curve of activity: the lag, the growth, stationary and death phases.
Some things I learned (but maybe I'm wrong), lets call them assumptions:
1. LAB can / will reproduce themselves in an anaerobe environment.
2. Yeast cell can reproduce themselves only in an aerobe environment.
3. Soon after refreshing/making a dough that include a part of your starter, all oxygen is used.
4. Yeast cells are mainly responsible for the lifting power by producing carbon dioxide.
5. LAB (some types?) will produce carbon dioxide but there lifting power is neglectable.
(I neglect, for now, that LAB do produce acids and yeast cells do produce ethanol, because my focus is carbon dioxide - lifting power)
So my confusion is: if we discard 50% of the starter by refreshing, we also discard 50% of the LAB and yeast cells. Soon after the refreshing the oxygen is used so yeast can't reproduce, but still I learned that frequent and timely refreshing delivers a starter with strong lifting power, but where does this lifting power comes from as yeast cells are decreased by 50% after every refreshment?
Can someone shine some light on this dilemma?
And possibly have answers on the following questions?
A. Do yeast cells (in a normal yeast dough, not sourdough) continue multiplying itself or is this almost immediately stopped after kneading?
B. Do yeast cells (in a refreshed starter or dough with just added starter) continue to multiply or is it stopped rapidly after mxing?
Wim
Assumption #2 is incorrect and therefore the answer to both questions is yes, they do continue to multiply.
https://www.youtube.com/watch?v=-NspiG3y1R0&list=LLEXjTDXma4EYjuh1cqGpYDg&index=4&t=0s
Please... so yeast? There is no yeast... is a starter (if he is right, and HE IS, i tried, ill post down a picture with an 90% hidration dough, un-laminated cause the time was random and never had time...) but he tells u basically that the starter itself is a dough, and actually u can do in theory ... very far stretched (or not? MYTHOLOGY!!!And like a perpetuum-mobile).. .but the truth is that you can bake bread as u wish and it will be amazing, so dont ask yourself this questions until you know (i am joking, here since forever, but baking time to time... hated that stickyness).... but is an infinite hidration dough possible? even in theory!
Which was the most hydrated thing used here, actually dough... all is dough, even if not salted, but even the starter itself, if starts with just water and flour... is a dough, it will proof..... at a certain time a certain amount... even if the starter is DEAD! (cause fermentation happens, and u stir something that ferments...)
The fact the dough is basically a dough, and kneading seems to be SO important... can u proof in no time? using a starter with a fairy dust?
Is a motherDough a dough which actually is a starter at lower hydration and recipes over recipes just about handling ferments... and others? so autolyse is a verrrry inactive starter mixed with the starter gives you a dough? or a starter... analogy, levain or dough, but a dough is a doug without a levain or a levain is the same thing as a dough? after that... you can't stop BAKING! is so interesting that your time gives you recipes and the recipes are given by your waitng,,, autolysing at infinity and refreshing or kneading the same thing! just 2 things... a dough... is nice, always! more then two and is good ... and is just fermentation.... anyways, that video speaks about passion... passion and technique is pure art and crafts
Happy bakes in covid times
When yeast make ethanol and carbon dioxide, they are actually doing so in an anaerobic reaction. They evolved to eat lots of sugar really fast, multiply like crazy and kill their aerobic competitors with booze. Pretty cool beasts!
This is a bit late but here is my limited insight. I became curious as a well after reading in Ken Forkish's book FWSY, that "once a dough is mixed, the yeast replicates until no more oxygen remains in the dough, at which point the yeast cells, as they consume sugars from the flour, begin to produce gases (carbon dioxide and ethanol). I have read from multiple sources since, that yeast populations can grow without oxygen, although less energy is produced which results in a much slower growth. As far as discarding sourdough culture, as you mention, doing so would surely deplete the yeast population if it could not multiply. Discarding is necessary to de-acidify the culture (bacteria and their byproducts greatly outnumber the yeast)
Best Regards,
Tom
Both LAB and yeast multiply. They will be put into a sleep state if the temperature goes above or below a certain threshold, or the salinity, or the acidity, go out of range, or the alcoholic content (in "beer"). Normally, if there is food, they reproduce.
The oven spring is due to both alcohol and CO2 being trapped in the gluten network. Alcohol will be turned into a gas and inflate the dough, too.
Yeasts reproduce better at lower temperatures than bacteria, which means that IMHO those who keep their starter in the fridge for weeks, or years, will skew the SCOBY toward yeast and away from bacteria, yeast will colonize the starter more and more. Ultimately you will have a yeast starter even if you think you have a "sourdough" starter. But that's just my assumption, I don't make sourdough bread and I don't know how it is supposed to be different from "yeast" bread.
You really should check that - and if you come up with the same theory - well - keep checking. Enjoy!