Author Topic: New starter procedure trial  (Read 33574 times)

evil_morty

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Re: New starter procedure trial
« Reply #270 on: October 10, 2015, 09:50:24 AM »
16 hours in - still nothing really.  since chilling the wort down to 48-50F and pitching the yeast I don't believe the chest freezer has even had to turn on.

Offline brewinhard

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Re: New starter procedure trial
« Reply #271 on: October 10, 2015, 11:15:41 AM »

While I appreciate the response, I am not sure that this explanation fully answered my question (please don't take offense).  Aren't both populations of yeast cells (a starter going to fermentation completion and a batch of beer wort fermenting to completion of which to be repitched as slurry) considered to be in quiescence?  And if so, wouldn't both of their UFA and ergosterol reserves pretty much be used up at this point, potentially making for a "not so healthy" pitch?

Thanks for helping me trying to wrap my head around this....


I may be wrong, but I believe that you are equating health of the pitch with the health of the fermentation.  That's not how things work.  Improved health and activity have one big advantage; namely, they reduce the lag phase.  The lag phase is the period of time between pitching the cells and the beginning of replication (i.e., the logarithmic or exponential phase).  It is not the period of time between pitching the cells and signs of fermentation.  That definition of lag phase is misnomer that is unique to the home brewing community. The lag phase is where cellular health is rebuilt by shunting O2 and carbon to the respirative metabolic pathway for the sythesization of ergosterol and UFAs.  Quiescent cells can become healthy cells, that is, if their cell walls have not been damaged via physical forces such as shear stress and there is enough O2 in solution.  Quiescent cells just require more time in the lag phase and more O2 than active cells that are pitched at high krausen.

The reason why we make a starter is to shorten what I am going to refer to as time-to-own.  Time-to-own is the period of time between pitching our culture and our culturing owning the wort.  None of our breweries are sterile.  Our culture is in a battle with other microflora that reproduce at a faster rate. Sanitize is not a synonym for sterilize.  Sanitized items still harbor live vegetative cells.  These surfaces just harbor far fewer vegetative cells than they did before they were sanitized.  This battle means that we need to do whatever we can to shorten time-to-own.   We do that by shortening the lag phase and/or the exponential phase.  My method attempts to shorten the lag phase via pitching at high krausen.  Cells at high krausen are active and have higher ergosterol and UFA reserves.   Cells pitched at high krausen have already started replicating by the time that quiescent cells have reversed the morphological changes that occurred at the end of fermentation and replenished their ergosterol and UFA reserves.

While the cells from slurry and a fermented to completion starter are quiescent, they are not quite equal.  We can look at the cells in slurry as tired battle hardened soldiers and the cells in a fermented-out starter as tired untested soldiers.  The cells in slurry have been through a "real world" fermentation in our brewery.  Starter wort is not a real world medium (at least not in American breweries :) ).  The cells that are not going to hack it in our brewery have already been weeded out in slurry via selective pressure.   An advantage that cannot be overlooked is the sheer number of cells available in slurry.  A 2L starter contains roughly 1/10th the number of cells in a 5-gallon batch.  While the lag phase is not shorter when pitching slurry, we have more control over the length of the exponential phase; hence, shortening time-to-own.  Anyone who has ever pitched the entire cake from a fermentation has witnessed how quickly active fermentation starts.  That's because the exponential phase has almost been completely eliminated.

In end, one should look at slurry as a brewery convenience, not the end all, be all of yeast cultures.  Repitching slurry is something that we adopted from the commercial world where the practice is critical to remaining profitable in many cases.  Ideally, we want to serially repitch to place selective pressure on a culture, plate the culture for isolates, and grow new seed culture from the best performing isolate.  If we go through that process enough times, we will end up with a culture that is robust in our brewery (however, me may not care for the flavor that it produces).

Thank you for taking the time to answer my question (yet again).  It seems that sheer stress may play a role in true cell health.  I really enjoyed your analogies to the battle "hardened" populations.  That helped to explain the difference between a slurry population and a starter population regarding quiescence. 

So it sounds like the best way to approach yeast management at the homebrew level might be to create a shaken 1 L starter (pitched after shaking, 4:1 size) pitched at high krausen, then subsequent repitches of slurry from the harvested primaries (at least a few times anyway before the population gets too mutated). 

Then start all over with a fresh pack as stated above. 

RPIScotty

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New starter procedure trial
« Reply #272 on: October 10, 2015, 11:18:18 AM »
I have to say, you're very good at avoiding the question and getting lost in long digressions. All you had to say was "yes" to brewinhard's first question. Slurry from an FV contains more cells than slurry from a starter simply because it has more biomass. The natural-selection argument is obfuscation.

I think you oversimplified the meat of Mark's post (and brewinhard's post) so you could use the word obfuscation. If you were bewildered or confused you should re-read the posts in succession.






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« Last Edit: October 10, 2015, 11:26:18 AM by RPIScotty »

Offline charles1968

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Re: New starter procedure trial
« Reply #273 on: October 10, 2015, 11:44:41 AM »
I have to say, you're very good at avoiding the question and getting lost in long digressions. All you had to say was "yes" to brewinhard's first question. Slurry from an FV contains more cells than slurry from a starter simply because it has more biomass. The natural-selection argument is obfuscation.

I think you oversimplified the meat of Mark's post (and brewinhard's post) so you could use the word obfuscation. If you were bewildered or confused you should re-read the posts in succession.






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Nope. The only significant differences between a starter that has been fermented out and a batch of beer that has been fermented out is that the starter is smaller. The yeast are battle hardened in both. Mark's argument that the yeast in a starter are untested and haven't been through a "real world" fermentation doesn't stack up. The yeast have indeed been through a full fermentation cycle and become quiescent, just like the yeast in a batch of beer.

Mark is saying that the yeast from a fermenter have adapted to the brewery through natural selection. That may be true in a brewery where the same yeast are pitched over and over again into wort of the same composition/temperature/pH etc. over dozens of cycles, but home brewers don't work that way. Most home brewers keep switching recipe, fermentation temperature, water treatment, and yeast type. A typical batch of yeast used by an average home brewer might go through one fermentation cycle before being repitched in a new kind of beer - no different from a starter yeast population being pitched from fermented out DME to an all-grain wort.

To be clear, I think the new starter procedure Mark is recommending is great and makes complete sense, but it doesn't follow that every detail of Mark's posts is correct.
« Last Edit: October 10, 2015, 11:48:57 AM by charles1968 »

Offline klickitat jim

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Re: New starter procedure trial
« Reply #274 on: October 10, 2015, 12:43:31 PM »
I'll avoid the parts of the debate about adaptation, whether or not size matters, etc. At first when I read mark's stuff about sheer stress caused by the stir bar I didn't think too much of that. But after trying it, to me there is a distinct difference in aroma between my stirplate finished starters and the few oxygenated non-stirred high krausen starters ive made. The oxygenated non-stirred high krausen starters smell fresh and tasty while the stirplate ones have a (for lack of better term) bitter, trub-like, unappealing aroma. Whether or not the cause of that off aroma is sheer stressed yeast, or even something that means those yeest are not as good, I don't know. But there must be something different, or they would look and smell the same. Couple that with my experience now of 4 consecutive batches taking off sooner and more actively than I am used to with stirplate starters, for me thats evidence enough that oxygenated non-stirred starters are the better way to go, for me.

Offline charles1968

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Re: New starter procedure trial
« Reply #275 on: October 10, 2015, 01:21:00 PM »
It works for me too. I now use the shaking method for starters and for rejuvenating old harvested yeast samples that have been in the fridge for several months.

Offline MerlinWerks

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Re: New starter procedure trial
« Reply #276 on: October 10, 2015, 03:05:42 PM »
Well it appears my high krausen window appeared a little earlier than expected, sneaky little devils. I inoculated the starter with 75ml of thick 4th gen slurry about 9p last night. At 3a I had a thin but healthy looking krausen, much like the pic of Denny's ferm bucket minus the braunhefe. At 9a the krausen was well on it's way to dispersing.

I don't expect to be in a position to pitch until late afternoon/early evening. At this point I'm not sure what I want to do. I still have 400 - 500ml of two week old slurry so the clock is ticking on that relative to pitching it straight. To be clear, I have no doubt the SNS starter will do the job, but if I wait on the slurry then I probably should make a starter with it next week anyway. So I may just pitch the slurry straight today and refrigerate the SNS starter. Next week ~8 hrs prior to pitching, decant, add some fresh starter wort to wake it up and hopefully catch it at high krausen.

I realize that pitching at high krausen is not mandatory for success, but it is something I would like to try. In the past I have always been slightly put off by pitching the larger amount of starter that is usually recommended.
« Last Edit: October 10, 2015, 03:11:51 PM by MerlinWerks »

Offline klickitat jim

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Re: New starter procedure trial
« Reply #277 on: October 10, 2015, 03:16:29 PM »
Yup, my first try at doing this method, I made the starters the night before brew day.  They were at HK on brew day morning. Used them anyway and it went fine. This week I made my starters bright n early brew day morning. They were at HK in 8 hrs and pitched then. That will be me schedule going forward.

S. cerevisiae

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Re: New starter procedure trial
« Reply #278 on: October 10, 2015, 04:01:05 PM »
Thank you for taking the time to answer my question (yet again).  It seems that sheer stress may play a role in true cell health.  I really enjoyed your analogies to the battle "hardened" populations.  That helped to explain the difference between a slurry population and a starter population regarding quiescence. 

So it sounds like the best way to approach yeast management at the homebrew level might be to create a shaken 1 L starter (pitched after shaking, 4:1 size) pitched at high krausen, then subsequent repitches of slurry from the harvested primaries (at least a few times anyway before the population gets too mutated). 

Then start all over with a fresh pack as stated above.

What I have been attempting to say while avoiding being backed into a corner is that there is no one best way to propagate a yeast culture.  One's yeast management system has to be looked at as a whole.  We really do need to look at how we handle yeast as a system, not a collection is disparate steps.   My method of making a starter is just one part of my yeast management system.  There are parts that deal with the collection and isolation of yeast.  There are parts that deal with long-term viability.  There is component that deals with the harvesting and management of slurry (e.g., how much pressure can I place on a yeast culture before it mutates).  Every strain has to be observed on an individual basis, and adjustments to the steps have to be made.  That's why I maintain a paper-based log.

Let me give you an example of where making a decision in one part of a yeast management system could lead to a faulty conclusion of how a strain would perform in another area of the system.  I have a strain in my bank called FST 40-219/UCD 1219.  This strain was deposited into the UC Davis culture collection by the old Acme Brewing Company in 1942.  I am not exaggerating when I say that this strain is a pain in the backside to grow on solid media (plates and slants).  I dread having to subculture it, and plating it is not much fun either.   I had to write the one of the curators at UC Davis and ask if she had sent a blank slant by accident.  Her answer was "No, that is how the culture grows."  She told me that culture was a diploid, and that I should see how it grows on a plate.  I had to pull out a magnifying glass to see that there was a light film of yeast cells on the surface of the slant.

Anyway, I decided to skip subculturing the slant, and use the fill the slant with a few milliliters of autoclaved wort, attempt to suspend whatever cells are on the surface of the slant, and use that wort to inoculate 40mls of autoclaved wort trick.  To my surprise, the liquid culture started within a normal period of time.  I then stepped the culture after streaking a plate for singles.  The difference between performance on solid and in liquid media was like the difference between night and day.  The resulting beer was very good.  I also learned what the curator was saying when she wrote that I should see how the strain grows on a plate.  The colonies are smaller than most other cultures.  They look a lot like petite mutant colonies.  I almost discarded the culture based on my initial experience with solid media.   That's why it is critical to observe and document the performance of every culture that one brings into one's brewery from the start of use to the end of use.   


evil_morty

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Re: New starter procedure trial
« Reply #279 on: October 10, 2015, 04:52:21 PM »
23 hours, still no airlock activity.

typically I don't start to worry until 36 hours but I thought this method was supposed to get going quickly?

evil_morty

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Re: New starter procedure trial
« Reply #280 on: October 10, 2015, 04:52:58 PM »
at some point this may go from lager to a saison :P

(have some dry saison yeast in the fridge)

cracked the lid - nothing going on yet.  last time I used this yeast it was going at a good pace at this point but that's my only other sample point with it.
« Last Edit: October 10, 2015, 05:38:33 PM by evil_morty »

Offline brewinhard

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Re: New starter procedure trial
« Reply #281 on: October 10, 2015, 05:40:53 PM »
Yup, my first try at doing this method, I made the starters the night before brew day.  They were at HK on brew day morning. Used them anyway and it went fine. This week I made my starters bright n early brew day morning. They were at HK in 8 hrs and pitched then. That will be me schedule going forward.

That is the one thing that has kept me from doing this so far.  Brew day is busy enough for me already and to add another step (i.e. making a small starter early before heating up strike water) just adds to the chaos especially with two young kids in the mix. I will get there, but I want to get my hands on a fresher pack of yeast and will most likely do an ale instead of a lager first with this method. 

Offline brewinhard

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Re: New starter procedure trial
« Reply #282 on: October 10, 2015, 05:41:35 PM »
at some point this may go from lager to a saison :P

(have some dry saison yeast in the fridge)

cracked the lid - nothing going on yet.  last time I used this yeast it was going at a good pace at this point but that's my only other sample point with it.

I am assuming you aerated your wort properly?

evil_morty

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Re: New starter procedure trial
« Reply #283 on: October 10, 2015, 05:47:37 PM »
at some point this may go from lager to a saison :P

(have some dry saison yeast in the fridge)

cracked the lid - nothing going on yet.  last time I used this yeast it was going at a good pace at this point but that's my only other sample point with it.

I am assuming you aerated your wort properly?

wait what????

kidding.  I gave it a 90 count of pure O2 through a stone with the flow regulator set to 2 (LPM?  I can't remember the units on that thing).  it had a nice layer of O2 foam on top by the time I was done.

eta:  I also drain my kettle down about 9' to my fermentor so that gets it pretty well aerated as well.
« Last Edit: October 10, 2015, 05:50:41 PM by evil_morty »

S. cerevisiae

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Re: New starter procedure trial
« Reply #284 on: October 10, 2015, 08:53:51 PM »
23 hours, still no airlock activity.

typically I don't start to worry until 36 hours but I thought this method was supposed to get going quickly?

That's odd.  The fermentation should start as fast as any other method.  What strain did you pitch?   What was the starter gravity?   What was the batch gravity?