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How old can a starter REALLY be?

ElPanadero's picture

How old can a starter REALLY be?

Couple of other threads are branching off into discussion of the yeast Saccharomyces cerevisiae.  I thought therefore I would open a new one for better organisation and focus of topic.

I want to ask, just how old can one claim a flour-water "starter" to be?

First a couple of factoids about Saccharomyces cerevisiae.

1. The yeast cells double every 90-100mins or so

2.  The mean life span of a cell is 26 generations


100min x 26 = 2600 mins  which is 43 hours which is just short of 2 days.

Like our own human bodies, every cell that makes us what we are, dies off in time, but thankfully the cells are  replicated before that happens.  The replication time for our various cells varies tremendously but it is believed that the cells with the largest replication cycle are 10yrs.  The implication of this is philosophically intriguing.  It means you are no older than 10yrs no matter how old you believe you are, or at least there is no cell in your body older than 10yrs !  A counter philosophical thought is that everything that is "us" is made up of matter, and since matter can neither be created nor destroyed then all the matter that makes up our bodies has been here since the dawn of the universe itself, in which case we are many billions of years old.

What we choose to define as the "human being" defines how old we are.  If it's our cells, then we're 10yrs old, if it's the primordial matter, then billions of years old.

And so back to wild yeast starters and our good friend Saccharomyces cerevisiae.

If each yeast cell lives no longer than a couple of days, how in any true and just sense could it be said that there exists a "20 yr old grandmother starter"?   In looking for possibilities, I wonder whether this refers to some other elements of the starter that actually ARE 20 yrs old or is the whole notion simply a lot of kidology and hocus pocus?

Consider this.   I light a wood fire in the chimenea in my garden and feed it with a constant stream of new fresh fire wood.  For 20 years I keep it going and never once let the fire go out.  Tell me, is my fire 20yrs old?  Is there any part of it that is truly 20yrs old?   It has had new fresh wood constantly, and new fresh oxygen constantly, so surely the flames I am seeing are new fresh flames and all the gasses and products of combustion are equally being given off freshly.  Nothing in there is 20yrs old unless perhaps the ashes produced linger on for that length of time (but then do the ashes constitute the fire?).

I'm intrigured by this notion of these very old starters given that any starter is a symbiotic balance of yeasts and bacteria that are constantly fed, which replicate for a finite number of generations and then die.

Common sense says there must be "something" in these starters aside from the yeasts and bacteria that does somehow survive through the years or else it's all a bit disingenuous. 

Can anyone tell me what that "something" is?







adri's picture

Are you searching for a soul in sourdough starters? ;) This seems to be a more philosophical question and I'm not sure whether I can write something about it because of my English as a third language skills or.... well I'll give it a try.


I'm not sure for yeast, but for other fungii, spores can survive quite a long time. That our yeast forms spores you can see here:


ontopic again:

What do we want from a starter? That it has a good taste, gives good rise, ... And we want it to be stable. But what does "stable" mean?

In my opinion: It should give reproducible results. It should be strong against other germs. If neglected for a while it should recover.

You can see this as an ecosystem or society. The typical schoolbook example with insects and birds: If there is a lot of insects, birds have a lot of food. More birds will survive the winter and have more children. They will eat more insects therefore soon there will be less food for the birds. Therefore less birds. Therefore more insects.... An now add birds of prey, and plants eaten by the insects, ... and you'll have an ecosystem.

Such an ecosystem has more a moving equilibrium than a steady state. You can influence it from outside e.g. when a winter kills a lot of insects and the migratory birds won't find enough food in spring.

A "stable" ecosystem should be able to recover from that. It needs more to influence it (like Monsanto, Sygenta and Bayer killing all insects.) An unstable ecosystem can easily be disturbed. In such a stable ecosystem, after a few years it won't be the same insects and same birds, but their children, grandchildren, great-grandchildren... and so on. But it is still the same ecosystem.

From an outside view: I'd say, if an ecosystem has been able to recover from a lot of turbulences like hard winters, hot or cold summers... and does not diverge in one direction if the outer parameters stay the same for a while (... and a while more)... you can consider it stable.

Transferred to sourdough starter: If it's been there for many years and always performed well, it is likely to have created a good and stable ecosystem.

Just my thoughts about it.


ElPanadero's picture

Appreciate the thoughts.  Not entirely sure you understood the question.  Let me try again.  In your last statement you said :

"If it's been there for many years and always performed well, it is likely to have created a good and stable ecosystem"

My question is, is there any part of that good and stable ecosystem that is actually years old?  I'm suggesting that any yeasts in there will no no older than 2 days.  Do you agree?



adri's picture

The US American society is no older than 114 years and 252 days as it is the age of Jeralean Talley is the oldest citizen?

MisterTT's picture

point of view I could say that there is still a portion of flour and water that were used to start the starter, and a portion of flour and water of subsequent feedings. This is pretty simple to realize, knowing that the amount of initial flour/water decreases exponentially (assuming a perfectly homogenous starter), but the exponential function is always positive and is only zero "at infinity". This is limited, of course, by the elementary parts (molecules, atoms, whatever you would care to take into account) of initial flour/water, that is, when you get less than half of an atom remaining (by calculation, in practice this isn't actually possible), the original flour/water mixture is extinct.

This is all moot, however. Exponents die down so quickly that an AP starter can get converted to rye in about three feedings, so there is no practical use to these considerations. I'm no biochemist, but I think that when a stable ecosystem of various microorganisms is reached in one starter or another, it stays very much the same if not messed with too much. The notion of "old" starters is much more romance than fact in my opinion.

Joyofgluten's picture

"The notion of "old" starters is much more romance than fact" I'm with you fully on that.

srulybpsyd's picture

This sounds like some deep stuff!

Would a practical appliication of this question be: What is the benefit of maintaining a starter over long periods of time, unless one bakes with it very frequently?

(For instance, if I only bake sourdough bread every once in a while, is it worth expending the effort (and money) maintaining it, or would it be the same if I started from scratch each time?)

MisterTT's picture

by maintaining it rather than starting a new one each time :) That's the best reason to maintain it that I know. However, there are some archaic recipes that just call for flour and water and are done over several days, I've seen a thread about one not too long ago.

DavidEF's picture

As far as I can logically deduce, there is no part of the starter that can be years old. It would have been diluted out in days, if fed every day, or at least in weeks or months. But, the ecosystem is the surviving part. The U.S.A. is hundreds of years old, some of the individual states are older than the U.S.A. and some younger. Cities have an even wider range of ages. But the people, plants and animals are different now than they were then. Only the ecosystem is the same, and not even that is completely so, as the character of the ecosystem is influenced by the current generation living in it.

There is a benefit to an ecosystem getting older, whether it be a human governmental organization or a sourdough starter. That is, the changes that take place in the environment, especially catastrophic changes, tend to strengthen the ecosystem by weeding out the weakest elements and catalyzing adaptation in the survivors. Survival of the fittest, so to speak. But not just survival, thriving.

Look at the ever present problem of sickness and disease. We try to kill the germs, but a few survive and multiply. Their children are resistant to the thing that killed the others, so we have to keep coming up with new ways to try to kill an ever-adapting ecosystem. That ecosystem gets stronger as it faces trials, because the weaker elements of the ecosystem are being reduced, leaving the stronger elements to reproduce.

ElPanadero's picture

Whilst I don't disagree with your thoughts there, my feeling and thus assertion here is that if a company wants to sell me something they call a 10yr old starter, they are in fact being very disingenuous.  All they are really selling is a very fresh (or fairly fresh)  stable culture/environment/ecosystem call it what you will, and no part of it whatsoever is actually 10yrs old.

Yet a quick glance on eBay for example shows the following for sale:

"Authentic fresh 14 year old  San Francisco Wild Yeast Sourdough Starter"

"120g Fresh 15 year old Derbyshire Wild Yeast Sourdough Starter - Organic"

"100 plus Year Old Alaskan Sourdough Starter (whole wheat)"


Now, I can imagine that by taking an active stable sourdough culture and drying it out and grinding it to a powder (maybe also freezing it), it could be kept for a significant period of time, but 15-100yrs ???  Now that does seem to be somewhat of a stretch don't you think?


Antilope's picture

you dilute it until you can't detect it anymore. Then you have to believe. ;-). Placebo starter? Just kidding! 

David Esq.'s picture
David Esq.

I saw a circus claiming to be the greatest show on earth. Seemed a bit of a stretch. Indeed any advertisement seems so to me. 

dabrownman's picture

now 40 years old and a real SF one at that.  Over the years I have folded in a countless number of other starters, fed it all kinds of strange 'flours' and liquids, nearly killed it many times, sent it all over the world more than once,  revived it from frozen and dry storage, folded them in too.  I like to say that I have a 40 year old survivor instead and what it survived was humans:-)

It isn't anything like it was when new or even last year for that matter - it changes all the time - from feeding to feeding - day to day.  It makes the perfect working pet.  Doesn't eat much and there is never any waste, since I store a small amount in the fridge and use it all, recovers easily when ill without any vet bills or medications, is nearly impossible to kill accidentally but easy to murder.  It could outlive me several times over no problem if I can find it a new master and so on,  easy to house train, does the right thing and what is supposed to do it every time too.  No education required but that is not why it isn't much of a talker, thinker or writer but an artist it is indeed.  Doesnlt hold a grudge, never complains and doesn't wear cloths, is not addicted to shoes or needs to have its fur washed either.  It won't try to hurt you unless you try to feed it too much or too often or you hurt it - which is only fair.  It is pretty much on an even keel, isn't much of huger or lovey or even emotional in any way, but it is very easy to travel with and transports anywhere without problem and would never do a #! or #2 that messes the car and you don't have to find and pay for a mate to reproduce it or pay to entertain it in any way  - just perfect really.

I would be surprised if many SD cultures had much if any Saccharomyces cerevisiae in them since it is hardly ever found in SD cultures - Candida humilis or Saccharomyces exiguus usually populate sourdough cultures according to much research but your particular one could have one or more of many living together.. 

Yeast can live longer than 2 days depending on the temperature and hydration mostly.  I like to put 7-8 days on the yeast in my culture rather than 2 but i have no way of knowing for sure.  I would also like to think that human civilization has lasted thousands of years even though the original folks are long dead.  SD cultures are like yeast and Lab (and who knows what else.) civilizations would be closer to the truth.

I do know that I have frozen and dried version of my SD starter that are much older than a week too and perfectly alive and well due the temperature and or hydration.   Yeast can also reset their biological clocks back to zero depending on what happens to them and circumstances.

Yeast is probably the most scientifically studied living thing on the planet but still we know so little and what we though we knew has been proven proven wrong:-)  Not too long ago some scientists of the era  didn't think yeast was even a living thing,   my how things change.  I do predict that when we find life on another planet it will much more closely related to Lab and yeast living comfortably together in a civilized way than a cute ET, loosely resembling humans,  that has a finger that lights up.

Yes, it is a 40 year old surviving, if primitive, civilization....

ElPanadero's picture

eloquent and witty.  But if I cherry pick the salient part you say you estimate your yeast's lifespan at 7-8 days which is fine.  My question however is whether or not it is true to claim that anything in your starter, any part of it at all, is actually 40yrs old.  No-one so far has been able to identify or cite anything in a flour-water starter that could possibly live for more than a few days let alone many years.

What we have had are some notions concerning alternative definitions of things which we might claim are many years old, for example the American Society or your "human civilisation".   The thing is you can't bag, tag and sell a "human civilisation".  But we do seem to be able to bag, tag and sell something that purports to be a 15yr old starter.  What do you think about that?  Do you not think it is somewhat disingenuous?  What is there that can be 15yrs old in such a product ?  EVen if we consider your notions of things that have survived within it, they have surely only survived for a handful of days as before that the hadn't even been born so to speak.

I'm still open to the possibility that there might still be "something" in a starter that can and does survive for years and years but if so I have no idea what it is.  If there isn't then surely every single sourdough culture or dry mix being sold today is really a fairly fresh one and certainly not years old.  Thoughts?



dabrownman's picture

brought back 10,000 year old ice from Antarctica to make SD bread and a 10,000 year old starter - talk about old - Lucy was very jealous too.  Whole grain berries can be stored for 30 years or more before being used without too many ill effects - if stored properly.  I'm sure I had some of that grain that the government stores for emergency uses which was rotated into the military mess for use to keep their stores less than 30 years old.

The Navy made great bread by the way regardless of how old the grain might have been and the cooks made the best military food by far too - but no sourdough except for dried SD mix for pancakes and waffles.  Wild yeast can also be stored for a very long time and used in a starter and for the first 8 days ,be really old in a SD culture before it dies

One of my dried starters is now over a year old - no worries  It can revived with 3 feedings and be over a year old.  The normal starter would have water, if pumped from from an aquifer that could perhaps be very old too and the grain, sadly, could also be older than we think, and probably is, but we would never know.  So some things in a starter can be much older than 8 days, including the yeast.

I have to admit that I bought some whole wheat berries at Winco when they had their grand opening, for 28 cents a pound  and froze them.  They could eventually become part of the starter in a few years.  I'm guessing i could make a starter out of it too and the yeasts and Lab on the grain would still be viable too so for 8 days it will be a few years old.

I'm pretty sure that if a company is selling a starter that really was begun 30 years ago, no matter how may interactions it has gone through, as a 30 year old starter, you probably couldn't sue them for false advertising and win.   It would surly be considered a nuisance suit.  In your country you would have to pay the costs of the winner if you lose - unlike here - so you want to bring the suit against them here for sure:-)

I don't see any harm or foul in their advertising - so don't put me on the jury!

You are a very interesting person talk with and you get me thinking about things I never would have even dreamt of,

ElPanadero's picture

DA.  Whatever mix of discussion we have, you have a handful of different ingredients to throw in it and zing it up.

We may not reach the answers we are looking for but the journey along the way is worth more than the end result.

I'm glad it gets you thinking . . .

"To wonder is to begin to understand" - (Jose Ortega)

gerhard's picture

A real dilemma which kind of reminds me of products that have original recipe and improved printed on the same label.



wassisname's picture

Fun topic, but first, define the term, “starter”. 

Is it a culture of organisms?  Then, yes, it can be old.

Is it a set population of individuals?  Then, no, it can’t be old.

But where’s the fun in that?

We humans are a sentimental bunch, even if we don’t like to admit it.  So we personify something like a culture of microorganisms to amuse ourselves.  Remember pet rocks? 

We talk about “killing” our starters, too… same problem if you really want to go deep with it.

As long as it raises my bread it can be whatever age it likes :)


Mini Oven's picture
Mini Oven

and the epigenetic factors involved?   Those environmental switches can be locked in for thousands of beastie generations until forced to change or die out.  The DNA isn't changing with each generation.  How the present beasties deal with present conditions changes and that gets passed on.  Evolution.  Still part of the past generations adding age to the starter.  

Those little wild yeasty beasties have been around a long time before they ended up in our starter where we nurtured them.  Where were they before the grain?  and before that?  and before that?   Do you honestly think they didn't have relationships with bacteria before?  These little guys are professional workers breaking down organic materials.

Does discarding into the compost or pouring down the drain end a bacterial strain?  probably not  (Baking does a bit a damage.)

I think these little beasties are older, much older than we are or ever will be.  We humans are just too complicated. :)


ElPanadero's picture

Well Dabrownman, I think Mini just bowled us a "Googly" or is it a "Yorker", I never did follow cricket !

A 45 million year old yeast lying dormant in amber?   That is interesting.   Life finds a way to cling in the most desperate of places it seems.   I wonder if there is a more practical way to harness this "hardiness" of yeast.  The yeasties in our cultures seem to die off if we don't feed them for a few hours or days, yet encased in an amber chamber they can survive almost indefinitely.  Lots to think about here !   Many thanks Mini minx!


dabrownman's picture

poster child for scientific experimentation and genetic engineering- as it was the first thing to have its genome fully discovered.   I was reading a scientific journal that laymen like me should never read, that one genetic mutation of some kind happens in yeast about every 50,000 buddings or so.  Thankful,y these mutations are unusually in parts of the code the yeast no longer uses or needs or it kills of the poor cell that has the problem if serious enough a problem.  For humans, I'm convinced that most of DNA is not used by most of the folks either.  I mean what happened to people with pink, green, blue hair..... to match their eyes like it used to :-)  Never mind,  I jsut saw a guy with pink green and blue hair.

jcking's picture


1. The yeast cells double every 90-100mins or so

2.  The mean life span of a cell is 26 generations

Let's see if I follow. Cell Zero maintains life until gen 26 then Cell Zero dies. No? (how do it know when the 26 gen is born is another question (did you recently watch Blade Runner? "Time to die")) Where does Cell Zero go? Vanish into thin air. Carted off in a "Hurry up Wagon"? Join the rest of the clan in you tasty loaf? Stay behind and check the use by dates of the fridge items? (sorry I'm feeling a little silly and wish not to disrespect EP or any of the posters)

In conclusion/confusion, do the old dead cells that may stick around count?


ElPanadero's picture

Ah yes . . . "Questions... Morphology? Longevity? Incept dates?"   (top top film !)

I did wonder about this too.  The cells replicate for their 26 or so generations and then expire.  They must therefore be in the mix.   I see 2 possibilities here.

1.  The repeated process of discarding and adding fresh flour and water must iteratively remove much of the dead cells.  There is a small chance that after X number of iterations a few dead cells from your "cell zero" generation may remain, but that chance gets smaller and smaller and smaller with every refresh.  I would say then that realistically all the dead cells in any starter are unlikely to be very old.  It IS possible by some amazing fluke of nature that a 10yr old dead cell could survive the thousands of discards and refreshes  but then i's also possible I could win the lottery with its 1 in 14million odds (if I did it which I don't !).

2.  The bacteria in the culture can perhaps feed on the dead cells?  I really don't know about this and maybe someone like Debra can enlighten us.  When things die they tend to revert to their "prima materia" over time and in the right conditions so I would think it possible that they could therefore become food.  Hmmmm

Cheers for the input


jcking's picture

Instant yeast in a dough left to ferment for more than a few hours will produce alcohol, gas and a small amount of acidity. Does this acidity come from dead yeast cells?


Mini Oven's picture
Mini Oven

:)  and dead bacteria and organic matter and some fermentation products...

"Amino acids are the building blocks of proteins, and yeast cells need a lot of them to grow, reproduce, and carry out a strong fermentation...  

Fortunately, a protective dose of amino acids, in the form of lysed (dead) yeast cells, can be added to juices and musts before fermentation begins. These dead yeast cells, sometimes also called “yeast hulls” or “yeast ghosts,” are essentially that: the leftovers of what were once living yeast cells. That may sound a little morbid, but there are a lot of amino acids, nitrogen, vitamins, and other useful goodies left over when yeast cells die en masse as they do after they’re done with fermentation."  


Frequent Flyer's picture
Frequent Flyer

The Meuse River in Europe is considered the oldest river in the world, dating 380 million years.  Yet I've always thought that Heraclitus was right when he said "You can never step into the same river; for new waters are always flowing on you. 
No man ever steps into the same river twice,  for it's not the same river and he is not the same man."

An old, even ancient starter is just some new bugs and yeasts with a noble ancestry.


ElPanadero's picture

Very well put sir.  :)

Frequent Flyer's picture
Frequent Flyer


rozeboosje's picture

This is like the Ship of Theseus all over again! :-)

Frequent Flyer's picture
Frequent Flyer

...the ship.  This thread has been educational and fascinating.


Muskie's picture

you're main point is about the advertising of starters. Assuming this is so;

  1. I purchased a couple of starters that where claimed to be from certain regions. I purchased them based on their claimed properties.
  2. I was told that my starters would evolve over time. The more they were used, the more the flavor would develop.
  3. I therefore assumed, that starters don't taste like they're advertised from the day I receive them, only after I have cultured them some.
  4. I therefore assumed, the taste of any given starter will evolve.

So does that mean it can devolve too?

I abused these starters. I recently revived one from > 9 months in a mason jar in a fridge. No feedings, nothing, just left to sit in a fridge. It took me 6 days, but it came back to life. It was never left exposed to air, and this was done in the middle of I'm leaning towards it was something in the original culture that formed yeast rather than something in the air, flour, or water I used to revive it. It wasn't frozen, and wasn't where'd the yeast come from using your theories?

I have since dried and frozen some of that starter. Its possible it might not get brought out of the freezer for 20 years...would it then be a 20 yr-old starter? Not in my opinion. I'd want it to have been used constantly over that time for me to consider it that old. As we know, the more you feed a starter and use it, the better it becomes. While this may just be selective evolution (we toss stuff that isn't tasty), its the only aspect of starter being old I care about (cause damn it, I want it tasty!)

Of course taste is a subject that comes into it too...

I am with the crowd who say, a workable starter is a starter, anything else is a work in progress. If I can feed it, and in 2 hours its doubled, its a starter. Will I love the bread it produces? Who knows, so many factors will influence that. But I've decided I would rather use my starter than dried yeast...for whatever reason, so its my only way to go.

I think, when I produce a loaf that is so amazing I say; "OMG, I gotta do that again", I will take that starter and dry and freeze it. I will likely do that with several batches of starter. And then I will stop propogating my starter and just keep using the dried and frozen bits to create new starters that, hopefully, will maintain that amazing point.

That will be for my everyday bread, I expect, though, I will maintain that original starter and see when it stops being amazing, or turns into my next amazing OMG starter...;-]

I liked the analogy of a starter being a pet. You can't buy a great pet, but you can nurture one. There's no "good" or "better" starter...just get one and learn to live with what you got, make it your friend, let it lick your hand and make you feel happy.

David Esq.'s picture
David Esq.

Genetic makeup. Genes copy themselves. And do a good enough jobs at it that they preserve memories and instinct  not only across an individual but across an entire species. 

Just like your your ten year old self having memories from 15 years ago. 

The real question is why would anybody about the pedigree of their starter? 

MarkS's picture

Cell 0 (generation 1) divides 90-100 minutes after "birth" into cells 1 and 2 (generation 2). 26 generations later, roughly 2600 minutes or so, cell zero dies.

My math could be off a little here... During the first 26 generation, the number of cells in the starter has grown to 67,108,864 (2^26). Each of these cells lives for 26 generations. Every 90-100 minutes each of these cells divide in two. That means by generation 52, there are 3.135285318820699159646624256897e+203 (3 followed by 203 digits) cells in the starter.

Point is that so long as the starter is fed, there is material for the yeast to consume and grow. The age of the starter has nothing to do with the age of the individual cells of yeast contained within. As an example, the human race is estimated to be 50,000-100,000 or so years old. It isn't a fallacy to say the human race is between 50,000 and 100,000 years old, even though no living human is older than 120 years.

Now, if someone states that the yeast in their 200 year old starter is 200 years old, then they are clearly in error.

ElPanadero's picture

the point I was making in the OP.  So when you say:

" It isn't a fallacy to say the human race is between 50,000 and 100,000 years old, even though no living human is older than 120 years."

I tend to agree (tho not sure about the 120yr part).   You can't bag up the human race and offer it for sale to someone as a 100,000 yr old entity.

Also when you say :

"Now, if someone states that the yeast in their 200 year old starter is 200 years old, then they are clearly in error."

I pretty much agree with this excepting Mini Oven's exceptional link where someone allegedly found a yeast encapsulated in amber that was millions of years old.

The question is however, if the yeasts aren't 200yr old, is there anything else in that starter mix that could be?

For the most part I think this is more romance than reality so when I see websites selling 15yr old starters I confess to being a little dubious and I think there is more than a little poetic license going on in terms of advertising.  Equally when I here about San Franciso bakers transporting their starter with armed escorts one can't help feeling that's a bit of a publicity stunt going on.  I'm sure there are all sorts of things in their starter to give it complex deep flavours and like Coca Cola they keep the "recipe" very secret.