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General Category => Yeast and Fermentation => Topic started by: gmac on October 10, 2012, 09:13:16 PM

Title: Over pitching/under pitching experiment
Post by: gmac on October 10, 2012, 09:13:16 PM
I did a 10 gal batch of pale ale yesterday split into two pails.  I had a cake of WLP007 in the fridge.  It had been there about 5 days so it had really settled into a hard cake and I dumped off the remaining beer.  Being the idiot I am, I tried to pour half of it into each fermenter but instead, I brick of WLP007 went splashing into one bucket and there was about a teaspoon of yeast left in the container (probably about as much as in the original tube minus the liquid).  So, it got dropped into the other. 

I am tempted to leave them as is but what do you think would happen.  I can't do anything for the over pitched but I can top crop some over to the under pitched if necessary. 
Title: Re: Over pitching/under pitching experiment
Post by: duboman on October 10, 2012, 09:18:36 PM
I'm intrigued to find out how each beer turns out.....staying tuned in for this one :)
Title: Re: Over pitching/under pitching experiment
Post by: davidgzach on October 10, 2012, 09:47:06 PM
Let it fly and see what happens to the underpitched one.  If there is no activity in ~48 hours you can always add more yeast. 

Dave
Title: Re: Over pitching/under pitching experiment
Post by: ethalacker on October 10, 2012, 10:56:41 PM
I had a similar circumstance happen to me.  I put a blow off tube on the overpitched fermenter and attached it to the underpitched one.  Both beers came out great.
Title: Re: Over pitching/under pitching experiment
Post by: euge on October 11, 2012, 12:01:42 AM
It'll ferment. You might see a big lag. Interesting to see the difference in taste and quality when it turn out. You must report back!
Title: Re: Re: Over pitching/under pitching experiment
Post by: Mark G on October 11, 2012, 02:35:26 AM
I had a similar circumstance happen to me.  I put a blow off tube on the overpitched fermenter and attached it to the underpitched one.  Both beers came out great.
I like this idea. It's top cropping without any of the work. And odds are, with the huge pitch on the first half, it will be spewing yeast over within a day or two.
Title: Re: Over pitching/under pitching experiment
Post by: tygo on October 11, 2012, 02:49:14 AM
Yeah, blowing off from the overpitch to the underpitch is a great idea.  On the other hand, I would be tempted to let it ride for experimental purposes.
Title: Re: Over pitching/under pitching experiment
Post by: euge on October 11, 2012, 03:06:12 AM
I hadn't thought about that approach. I guess theoretically you could just go on forever by timing your batches every three days or so!

Of course this doesn't take into account any mutations and bacteria.
Title: Re: Over pitching/under pitching experiment
Post by: gmac on October 11, 2012, 03:47:26 AM
Ok. I will let it ride.
First report is that the overpitched is bubbling frantically with a huge krausen 24 hours after pitching. The under pitched still looks like wort with a few bubbles.
Nothing earth shattering there.
OG on this was 1.058 by the way so it's not a huge beer anyway.
Title: Re: Over pitching/under pitching experiment
Post by: beersk on October 11, 2012, 07:48:34 PM
Can't wait to hear the results.
Title: Re: Over pitching/under pitching experiment
Post by: morticaixavier on October 11, 2012, 08:13:09 PM
I'll stick my neck out there and make a prediction.

Overpitched will end up with more esters
underpitched will end up with more fuesels and possibly higher TG
Title: Re: Over pitching/under pitching experiment
Post by: euge on October 11, 2012, 09:57:42 PM
You could top-crop and screw the experiment! Save the Beer!
Title: Re: Over pitching/under pitching experiment
Post by: gmac on October 11, 2012, 10:47:52 PM
After about 36-38 hours, the over-pitched beer has actually started to slow down dramatically.  I think it could be on the way to done but I've gotta pull a hydrometer sample to see.
The under-pitched is actively working and I'm not gonna top crop cause it is going strong but it is probably way behind.  Again, the hydrometer will have to tell the tale. 
I've gotta keg some beer tonight so when I have things sanitized I'll pull some samples but I figured an observation was probably due.
Title: Re: Over pitching/under pitching experiment
Post by: davidgzach on October 12, 2012, 12:53:51 PM
I had a similar circumstance happen to me.  I put a blow off tube on the overpitched fermenter and attached it to the underpitched one.  Both beers came out great.

How did you release the pressure?  I'm picturing a blowoff tube from one grommet to another.  If that is the only outlet for each, how did you account for the change in pressure going in to the underpitched batch?  Or am I missing something obvious?  Happens to me sometimes..... ???

Dave
Title: Re: Over pitching/under pitching experiment
Post by: DrewG on October 12, 2012, 03:22:02 PM
Quote
How did you release the pressure?  I'm picturing a blowoff tube from one grommet to another.  If that is the only outlet for each, how did you account for the change in pressure going in to the underpitched batch?  Or am I missing something obvious?  Happens to me sometimes..... ???

Carboy caps would work, methinks. Airlock in one hole and a tube in the other?
Title: Re: Over pitching/under pitching experiment
Post by: weithman5 on October 12, 2012, 03:47:39 PM
i would think this would work well from one bucket to another as the pressure would not likely be as much a concern in terms of breaking a carboy. the active ferment would have the higher pressure and discharge to the lower pressure system.
Title: Re: Over pitching/under pitching experiment
Post by: gmac on October 12, 2012, 04:28:09 PM
If I were going to do it, I would just put the hose in the top of the carboy and cover it all with foil.  It's not gonna be on there for long, you don't want to over pitch the receiving carboy either.  I'd say an hour would be more than enough.

For a bucket I wouldn't do this.  You'd be better to top crop and be done with it in 5 minutes.
Title: Re: Over pitching/under pitching experiment
Post by: dimik on October 15, 2012, 01:47:32 PM
Jason did a nice experiment about that a while back. Take a look:
http://sciencebrewer.com/2012/03/02/pitching-rate-experiment-part-deux-results/
Title: Re: Over pitching/under pitching experiment
Post by: kylekohlmorgen on October 16, 2012, 01:27:01 PM
Jason did a nice experiment about that a while back. Take a look:
http://sciencebrewer.com/2012/03/02/pitching-rate-experiment-part-deux-results/

This is a good read - make sure you get to the bottom for Garrett Oliver's advice!
Title: Re: Over pitching/under pitching experiment
Post by: tschmidlin on October 20, 2012, 06:44:11 AM
Jason did a nice experiment about that a while back. Take a look:
http://sciencebrewer.com/2012/03/02/pitching-rate-experiment-part-deux-results/

This is a good read - make sure you get to the bottom for Garrett Oliver's advice!
My only issue with what he says is this
Quote
Conversely, overpitching ages the culture – fewer daughters, over time, leaves you with a lot of battle-weary scarred cells with inflexible membranes that are no longer at their best. And not as many young, scar-free new cells.
If there are fewer daughters because the yeast aren't dividing as much, then the mothers will have fewer scars - the scars come from budding which is why they are called bud scars.  He is really talking about two different kinds of yeast aging, chronological and replicative.

There will be just as many scar free cells when you over pitch vs. under pitch - half.  1/4 will have 1 scar, 1/8 will have 2 scars, 1/16 will have 3 scars, etc.

His point is still fair though - older cells don't perform as well.
Title: Re: Over pitching/under pitching experiment
Post by: Kaiser on October 20, 2012, 12:17:27 PM
There will be just as many scar free cells when you over pitch vs. under pitch - half.  1/4 will have 1 scar, 1/8 will have 2 scars, 1/16 will have 3 scars, etc.

This is exactly what I said when Jason pointed me to Garett's comment after I commented in the surprisingly low gravity of the underpitched beer. He didn't let me disagree with Garett and I ended up researching the topic on-line. I found that a yeast culture will have the distribution Tom mentioned unless sedimentation creates an uneven age distribution. Older cells are bigger and heavier and as a result will settle first. But that doesn't apply here.

Kai
Title: Re: Over pitching/under pitching experiment
Post by: dimik on October 22, 2012, 04:43:29 AM
I've had my share of disagreements with Jason (purely healthy scientific discussion) and I respect his results and observations even if I disagree with them sometimes.
Title: Re: Over pitching/under pitching experiment
Post by: tschmidlin on October 22, 2012, 06:29:48 AM
There will be just as many scar free cells when you over pitch vs. under pitch - half.  1/4 will have 1 scar, 1/8 will have 2 scars, 1/16 will have 3 scars, etc.

This is exactly what I said when Jason pointed me to Garett's comment after I commented in the surprisingly low gravity of the underpitched beer. He didn't let me disagree with Garett and I ended up researching the topic on-line. I found that a yeast culture will have the distribution Tom mentioned unless sedimentation creates an uneven age distribution. Older cells are bigger and heavier and as a result will settle first. But that doesn't apply here.

Kai
He didn't let you disagree? ::)  That's lame, I don't know Garrett but I imagine he would have listened to your point.  The fact that Jason wouldn't listen doesn't speak well for his scientific mindset.  In the end I guess it was worth it because you proved something to yourself.  Did you ever go back to him with evidence, or did you decide it wasn't worth your time?
Title: Re: Over pitching/under pitching experiment
Post by: nateo on October 22, 2012, 12:20:55 PM
His point is still fair though - older cells don't perform as well.

How old is "older?" Would that happen in a single batch of beer, or are you talking about repitching?
Title: Re: Over pitching/under pitching experiment
Post by: gmac on October 22, 2012, 02:03:19 PM
Gonna keg this today and keep some for re-pitching.  Based on this, would it be better to keep the yeast from the underpitched or the over pitched for a porter (WLP007).  Gonna keg today and brew tomorrow.
Will update with FG and comments later.
Title: Re: Over pitching/under pitching experiment
Post by: davidgzach on October 22, 2012, 04:39:20 PM
Gonna keg this today and keep some for re-pitching.  Based on this, would it be better to keep the yeast from the underpitched or the over pitched for a porter (WLP007).  Gonna keg today and brew tomorrow.
Will update with FG and comments later.

I would say overpitched but can't wait to hear other responses on that.

Dave
Title: Re: Over pitching/under pitching experiment
Post by: davidgzach on October 22, 2012, 04:41:15 PM
Quote
How did you release the pressure?  I'm picturing a blowoff tube from one grommet to another.  If that is the only outlet for each, how did you account for the change in pressure going in to the underpitched batch?  Or am I missing something obvious?  Happens to me sometimes..... ???

Carboy caps would work, methinks. Airlock in one hole and a tube in the other?

That makes sense.  There has to be a way to relieve the pressure from the combined system.

Dave
Title: Re: Over pitching/under pitching experiment
Post by: davidgzach on October 22, 2012, 04:44:21 PM
If I were going to do it, I would just put the hose in the top of the carboy and cover it all with foil.  It's not gonna be on there for long, you don't want to over pitch the receiving carboy either.  I'd say an hour would be more than enough.

For a bucket I wouldn't do this.  You'd be better to top crop and be done with it in 5 minutes.

That makes sense too!
Title: Re: Over pitching/under pitching experiment
Post by: tschmidlin on October 22, 2012, 06:07:36 PM
His point is still fair though - older cells don't perform as well.

How old is "older?" Would that happen in a single batch of beer, or are you talking about repitching?
This is a more complicated question than it may seem :)

There are two ways that scientists talk about how old a yeast cell is - replicative lifespan, and chronological lifespan.  Neither of these is investigating the health of cells that are fermenting without dividing over time so the results may not be directly applicable.  With that caveat . . .

The replicative lifespan of yeast is roughly 25, meaning it can divide 25 times before it stops.  I am making a broad generalization here because it is strain specific.  This number comes from my old labs' work on strains BY4741 and BY4742, common lab strains that are the opposite mating types but otherwise the same.  I never did lifespans on any brewing strains because it is a huge pain and requires a dissecting microscope - basically, you plate cells, use the dissector to move individual cells to their own spot on the plate, then incubate for 2-4 hours.  Then you go back to the scope and pull the daughter cell away from the mother, put it in a garbage area, and count that as one.  You do this again and again until the mother stops dividing.  You can't let it grow too long or it can become hard to tell the mother from the daughter, or you may count the daughter's daughter as a daughter of the mother.  It is very labor intensive - we had a group of people who did nothing but pick daughters all day long because they went through the entire yeast deletion collection, ~5000 strains that are the same as above but with a single gene deleted, plus controls, etc.

Anyway, older mothers don't perform as well as younger mothers.  Daughters of older mothers don't perform as well as daughters of younger mothers, although they recover after a couple of generations.  I believe in this case "perform" means grow, they were not checking for fermentation performance or anything like that.

The other kind of aging, chronological aging, is quite a bit different.  In this case, a strain is grown to stationary phase and let sit for some period of time and then tested to see if it will grow again.  Again, the entire yeast deletion collection was screened by a guy I know (much easier for one person to do).  The normal strain was 50% viable at ~2 weeks.  This is misleading though, because the media used affected the results.  Another guy I know showed later that the effect was almost entirely due to pH, and more specifically the ability of the strain to withstand acetic acid.

So, will this happen in a single batch of beer?  The scales for a single fermentation are too short to apply to either one of these sets of data.  If you are constantly repitching replicatively older cells I think you will notice in your fermentations.  But isolating replicatively older cells is a real pain, labs have spent years trying to figure out how to enrich a culture for older mothers.  If you are harvesting from a carboy don't worry about it.  From a conical, as long as you are blowing out the first bit to get rid of the trub, don't worry about it.

If you are constantly over pitching and re-pitching from an over pitched batch, you may be increasing the chronological lifespan of the culture.  However, the data there are not good enough to give a definitive answer.  We know there are pH effects, but the final pH of the research media is not in the same range as beer, the finished culture ends up much lower than beer (under 3) while the buffered cultures they used are higher than beer (pH = 6).  And they didn't do anything with serial repitching of these cultures.

I think I typed all of this stuff and didn't answer the question.  Bottom line - if you follow standard practices you should be fine.  Make starters, aerate well, pitch in the suggested range, etc.  If a culture gets old by sitting for a while, refresh it in a starter.  Don't worry about bud scars.
Title: Re: Over pitching/under pitching experiment
Post by: dimik on October 23, 2012, 01:43:36 AM
His point is still fair though - older cells don't perform as well.

How old is "older?" Would that happen in a single batch of beer, or are you talking about repitching?
This is a more complicated question than it may seem :)

There are two ways that scientists talk about how old a yeast cell is - replicative lifespan, and chronological lifespan.  Neither of these is investigating the health of cells that are fermenting without dividing over time so the results may not be directly applicable.  With that caveat . . .

The replicative lifespan of yeast is roughly 25, meaning it can divide 25 times before it stops.  I am making a broad generalization here because it is strain specific.  This number comes from my old labs' work on strains BY4741 and BY4742, common lab strains that are the opposite mating types but otherwise the same.  I never did lifespans on any brewing strains because it is a huge pain and requires a dissecting microscope - basically, you plate cells, use the dissector to move individual cells to their own spot on the plate, then incubate for 2-4 hours.  Then you go back to the scope and pull the daughter cell away from the mother, put it in a garbage area, and count that as one.  You do this again and again until the mother stops dividing.  You can't let it grow too long or it can become hard to tell the mother from the daughter, or you may count the daughter's daughter as a daughter of the mother.  It is very labor intensive - we had a group of people who did nothing but pick daughters all day long because they went through the entire yeast deletion collection, ~5000 strains that are the same as above but with a single gene deleted, plus controls, etc.

Anyway, older mothers don't perform as well as younger mothers.  Daughters of older mothers don't perform as well as daughters of younger mothers, although they recover after a couple of generations.  I believe in this case "perform" means grow, they were not checking for fermentation performance or anything like that.

The other kind of aging, chronological aging, is quite a bit different.  In this case, a strain is grown to stationary phase and let sit for some period of time and then tested to see if it will grow again.  Again, the entire yeast deletion collection was screened by a guy I know (much easier for one person to do).  The normal strain was 50% viable at ~2 weeks.  This is misleading though, because the media used affected the results.  Another guy I know showed later that the effect was almost entirely due to pH, and more specifically the ability of the strain to withstand acetic acid.

So, will this happen in a single batch of beer?  The scales for a single fermentation are too short to apply to either one of these sets of data.  If you are constantly repitching replicatively older cells I think you will notice in your fermentations.  But isolating replicatively older cells is a real pain, labs have spent years trying to figure out how to enrich a culture for older mothers.  If you are harvesting from a carboy don't worry about it.  From a conical, as long as you are blowing out the first bit to get rid of the trub, don't worry about it.

If you are constantly over pitching and re-pitching from an over pitched batch, you may be increasing the chronological lifespan of the culture.  However, the data there are not good enough to give a definitive answer.  We know there are pH effects, but the final pH of the research media is not in the same range as beer, the finished culture ends up much lower than beer (under 3) while the buffered cultures they used are higher than beer (pH = 6).  And they didn't do anything with serial repitching of these cultures.

I think I typed all of this stuff and didn't answer the question.  Bottom line - if you follow standard practices you should be fine.  Make starters, aerate well, pitch in the suggested range, etc.  If a culture gets old by sitting for a while, refresh it in a starter.  Don't worry about bud scars.

THAT, Sir, was probably the most interesting thing I've ever read on any brewing forum. Very nice!
Title: Re: Over pitching/under pitching experiment
Post by: euge on October 23, 2012, 01:54:39 AM
I expect no less from Dr Schmidlin. Only wish this sort of insight was more frequent.
Title: Re: Over pitching/under pitching experiment
Post by: nateo on October 23, 2012, 01:57:40 AM
Tom - So if someone says "budding scars inhibit yeast performance in beer fermentations," that's probably specious reasoning?
Title: Re: Over pitching/under pitching experiment
Post by: gmac on October 23, 2012, 02:00:53 AM
older mothers don't perform as well as younger mothers.
Tell me about it...
Title: Re: Over pitching/under pitching experiment
Post by: yso191 on October 23, 2012, 03:13:29 AM
older mothers don't perform as well as younger mothers.
Tell me about it...

Ha!
Title: Re: Over pitching/under pitching experiment
Post by: tschmidlin on October 23, 2012, 06:02:03 AM
THAT, Sir, was probably the most interesting thing I've ever read on any brewing forum. Very nice!
I expect no less from Dr Schmidlin. Only wish this sort of insight was more frequent.
Thanks :)

older mothers don't perform as well as younger mothers.
Tell me about it...
;D

Tom - So if someone says "budding scars inhibit yeast performance in beer fermentations," that's probably specious reasoning?
Maybe, maybe not.  Bud scars do affect cell flexibility and will likely affect the ability of cell surface proteins to do their jobs.  But there are many changes to yeast cells as they age replicatively, including alterations in gene expression and decreased protein synthesis, so to attribute poor performance to bud scars is wrong in my opinion.  Bud scars are an indication of replicative age, and replicatively older cells perform worse - that doesn't mean that the scars are the cause.  The data I am familiar with indicates mixed results on the ability of scarred cells to get the nutrients they need effectively so that doesn't seem to be the case, but there may be more recent data that proves me wrong on that.

I should also point out that the end of a yeast "lifespan" is not death, it is senescence - the cell does not divide.  Whether it is alive and consuming nutrients or not can be hard to tell on a cell to cell basis, and I am not aware of any studies that came up with an definitive answer for that.
Title: Re: Over pitching/under pitching experiment
Post by: phillamb168 on October 23, 2012, 09:27:12 AM
So, old yeasts never die, they just produce more phenols?
Title: Re: Over pitching/under pitching experiment
Post by: tschmidlin on October 23, 2012, 04:22:38 PM
So, old yeasts never die, they just produce more phenols?
;D

They die of course, I'm just saying the experiments don't test for cell death.
Title: Re: Over pitching/under pitching experiment
Post by: bluesman on October 23, 2012, 04:35:59 PM
Great info Tom!

How would you explain yeast cells recovered from King Midas' tomb to produce DFH Midas Touch. Were they dead cells that were somehow rejuvenated or do the cells go into some sort of hibernation? Inquiring minds would like to know!
Title: Re: Over pitching/under pitching experiment
Post by: euge on October 23, 2012, 05:17:54 PM
Obviously some yeast are able to dehydrate and maintain some sort of suspended animation for lengthy periods. Also, I wouldn't expect all of them to survive- but the billions ought to be able produce a few that the scientists could culture. That would just be a statistical outcome.

Think about the yeasts found in the millions of years old piece of amber that have been grown- amazingly this particular strain shares the same DNA found in lager yeast.
Title: Re: Over pitching/under pitching experiment
Post by: denny on October 23, 2012, 05:21:09 PM
Obviously some yeast are able to dehydrate and maintain some sort of suspended animation for lengthy periods. Also, I wouldn't expect all of them to survive- but the billions ought to be able produce a few that the scientists could culture. That would just be a statistical outcome.

Or it's a great publicity vehicle....
Title: Re: Over pitching/under pitching experiment
Post by: tschmidlin on October 23, 2012, 05:35:06 PM
Assuming it was actually an ancient strain and not some modern contaminant, the most likely explanation is that the yeast sporulated, which would protect them.  The revived strain would not be exactly the same as the parent strain, but there would be some strong similarities.

I don't know the circumstances behind the discovery, but there are many things that could have contributed to the cells' ability to survive even without sporulating.  pH of the liquid over time, if it ever dried out and when and how, temperature stability, O2 levels, really just a host of factors that play into it.  And remember, viability of cultures depends a lot on the media used and is determined in research papers by growing them for a certain period of time after chronological aging and then measuring growth in some way.  These methods may be sensitive enough to note that a single cell is growing (they may not), but when the data are presented they are shown as a fraction of full viability and the plots trail downward over time.  So it goes form 100% to 0% on a single plot - anything below 5% is pretty close to 0% due to the size of the plot and the line thickness.  Anything at 1% is virtually indistinguishable from 0%.  Imagine what 0.0001% looks like - that's still a lot of viable cells :)

Finally, there is the phenomenon of "gasping".  Some cultures will start to grow again, long after the nutrients are depleted and when the plots show they are "0% viable".  This is not well studied, but I would speculate that the viable cells are scavenging from the dead cells, and this could create new cells in preparation for sporulation.
Title: Re: Over pitching/under pitching experiment
Post by: davidgzach on October 23, 2012, 05:55:27 PM
I expect no less from Dr Schmidlin. Only wish this sort of insight was more frequent.

+1 to that!
Title: Re: Over pitching/under pitching experiment
Post by: phillamb168 on October 25, 2012, 07:57:05 AM
Do Wyeast or White Labs carry any of these paleontological yeasts? As you say Denny, it's a great publicity vehicle...
Title: Re: Over pitching/under pitching experiment
Post by: denny on October 25, 2012, 03:48:29 PM
Do Wyeast or White Labs carry any of these paleontological yeasts? As you say Denny, it's a great publicity vehicle...

Although I have no evidence, I tend to believe it's as Tom suggested...some more recent contamination rather than a truly ancient yeast that's been magically revived.   But that just might be my inner curmudgeon coming out.....
Title: Over pitching/under pitching experiment
Post by: bluesman on October 25, 2012, 07:49:58 PM
Thanks for the insight Tom. Perhaps we'll never really know but believe as we may desire. It's at the very least an interesting story, not to mention a really fine beer. :)

Title: Re: Over pitching/under pitching experiment
Post by: tschmidlin on October 26, 2012, 07:12:48 AM
I think we COULD know, if we got a sample of the yeast and had it sequenced.  By comparing the genome of that yeast to those of known yeasts it may give us an indication of how closely related it is to modern yeast.  We couldn't confirm it as ancient that way, but we could confirm it as a modern yeast.
Title: Re: Over pitching/under pitching experiment
Post by: dimik on October 27, 2012, 05:31:01 AM
S. winlocki anyone?
Title: Re: Over pitching/under pitching experiment
Post by: tschmidlin on October 27, 2012, 07:24:48 AM
S. winlocki anyone?
Ha!  Had to google that one. ;D
Title: Re: Over pitching/under pitching experiment
Post by: klickitat jim on October 29, 2013, 01:10:50 AM
So.... what was the end result between over pitch and under?

I believe I finally found out what over pitch does.  Especially if it's not a high floccing yeast.

Anyway, this thread was awesome. But the OP never posted the results.
Title: Re: Over pitching/under pitching experiment
Post by: gmac on October 29, 2013, 03:16:41 AM
I would have sworn I did but obviously not.

The over pitched was far better and finished a point lower. The under had higher esters and was just more "homebrew-y" to make up a word. But in this case the differences in yeast numbers was dramatic. I wouldn't expect as much difference if the pitching rates were closer.
The over was just generally cleaner in this case. I wasn't able to monitor progress due to work so I can comment on the rate of attenuation.
Biggest difference was the over keg went fast, the under hung around for a while.