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Old 01-09-2017, 01:41 PM   #21
brewstergalVT
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Quote:
Originally Posted by sky4meplease View Post
I found myself in a position to split a propagation I have going of Wyeast 3522.
I would guess I had 40 billion cells in 500 milliliters of wort that was at the tail end of fermentation.
I split that into two 2,000 milliliter flasks with 1,500 milliliters of fresh wort in each. One on a stir plate and the other setting next to it. I will shake the non stir plate sample when convenient and when they are done I will do a cell count from each and post the results.
Wow, that's great! Thanks for doing the experiment, I look forward to reading your results!!

 
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Old 01-09-2017, 04:01 PM   #22
DurtyChemist
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So you want to see a 10 gallon batch split between a stir plate and just pitching a vial into a growler and shaken whenever a brewer remembers or would you just pitch into a growler and let it sit without shaking? Are you looking to see how fermentation is different (just OG & FG) or are you wanting to know if the taste is different between pitching a higher number of cells?

I have been meaning to brew 10 gallons so depending on what I have going on this weekend I MIGHT be able to do this. I think it could make for an interesting experiment plus it gets me brewing. Maybe I'll just keep it in mind for future brews and report back...if I remember this thread.

 
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Old 01-09-2017, 05:49 PM   #23
masaba
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Originally Posted by Gavin C View Post
Yes. Braukaiser has done lots of excellent work on this topic.

Here is a presentation of his from 2013.

The TL,DR version

Yeast growth in a starter (final biomass of yeast)

Stirred>shaken>no agitation



More from his excellent trove of info here
I don't think this is true. Other research shows that they all reach the final biomass, the stir plate just does it faster. And, as shown in this blog, the experiment by Chris White on this subject (which is used for the famous Mr. Malty calculator), was really conducted in an unrealistic setting where the stir plate was bound to work better.

http://www.woodlandbrew.com/2015/02/yeast-starters-stirred-vs-not.html?m=1

 
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Old 01-09-2017, 06:18 PM   #24
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Originally Posted by masaba View Post
...Other research shows that they all reach the final biomass, the stir plate just does it faster. And, as shown in this blog, the experiment by Chris White on this subject (which is used for the famous Mr. Malty calculator), was really conducted in an unrealistic setting where the stir plate was bound to work better.

http://www.woodlandbrew.com/2015/02/...s-not.html?m=1
Steven Deeds' limited data is often cited in these types of discussion as rebuttal to the conclusion garnered from Braukaiser's and others' work.

I'm curious why you agree with him that the Mr.Malty data and Chris White's chosen experimental model was unrealistic. I've not seen Mr. Malty data published. What was unrealistic about the model to you?

I don't share your interpretation of the Woodland data but I have no doubt others do.

But let's for sake of argument, assume it is accurate data; stirring only speeds up the process but will not result in more biomass.

I would counter by stating that a starter sitting there for 48+ hours versus one that's done in under half the time if stirred is potentially beneficial for a variety of reasons.

Putting cell numbers aside again brewers' yeast viability is shown to be improved via growth in an agitated media over one that is not agitated. That is all outlined in the 2013 paper I linked.

I've no dog in this fight. I just don't view the work done by Woodland and Braukaiser to be in the same league.

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Old 01-09-2017, 07:44 PM   #25
masaba
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Quote:
Originally Posted by Gavin C View Post
Steven Deeds' limited data is often cited in these types of discussion as rebuttal to the conclusion garnered from Braukaiser's and others' work.

I'm curious why you agree with him that the Mr.Malty data and Chris White's chosen experimental model was unrealistic. I've not seen Mr. Malty data published. What was unrealistic about the model to you?

I don't share your interpretation of the Woodland data but I have no doubt others do.

But let's for sake of argument, assume it is accurate data; stirring only speeds up the process but will not result in more biomass.

I would counter by stating that a starter sitting there for 48+ hours versus one that's done in under half the time if stirred is potentially beneficial for a variety of reasons.

Putting cell numbers aside again brewers' yeast viability is shown to be improved via growth in an agitated media over one that is not agitated. That is all outlined in the 2013 paper I linked.

I've no dog in this fight. I just don't view the work done by Woodland and Braukaiser to be in the same league.
Hey Gavin, thanks for responding. I really enjoyed your article in Zymurgy. I'm like you, I don't have a dog in this fight either, but I at least would like to let people know the variety of stuff out there so that they can make their own informed opinion. You are also correct that time for the starter to complete is an important factor! With that said, I will continue:

As far as I know, Steven is the only one who plots yeast growth vs. time in a starter culture. I skimmed Brukaiser's .ppt that you linked, and I cannot find how long he left the starters running. This should be on page 14 (his experimental setup page), but it is not. He mentions 'days old' a few times in the .ppt, but I believe this is a reference to how old the pack of yeast that he pitched was. He does plot some timelines in page 30 and 28, but unfortunately, these appear to be for fermentation and not comparisons of stir plate vs. agitation. So, since Steven is the only one who has actually gives results plotting yeast growth vs. time for different starter methods, I at least pay attention to it.

I think that it is up to each individual to figure out what works for them, but they should at least know all of the blog experiments that are out there in making up their mind.

 
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Old 01-09-2017, 08:20 PM   #26
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Quote:
Originally Posted by masaba View Post
...

As far as I know, Steven is the only one who plots yeast growth vs. time in a starter culture. ...
Thanks mate and I think it's just fine to put forward an alternate view.


I've yet to read any data that is in agreement with Woodland's findings WRT stirring v not

 
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Old 01-10-2017, 12:16 AM   #27
brewstergalVT
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Quote:
Originally Posted by DurtyChemist View Post
So you want to see a 10 gallon batch split between a stir plate and just pitching a vial into a growler and shaken whenever a brewer remembers or would you just pitch into a growler and let it sit without shaking? Are you looking to see how fermentation is different (just OG & FG) or are you wanting to know if the taste is different between pitching a higher number of cells?

I have been meaning to brew 10 gallons so depending on what I have going on this weekend I MIGHT be able to do this. I think it could make for an interesting experiment plus it gets me brewing. Maybe I'll just keep it in mind for future brews and report back...if I remember this thread.
What you propose is different from what I was asking but still a very interesting experiment as it takes things one step further. Of course the end result is what most homebrewers are interested in improving so your idea is great. I would say shake the non-stir plate starter as that's what I think most of us do that don't have a stir plate. If you end up doing it, maybe consider doing a triangle test with the two beers when all is done. Thanks for your interest!

 
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Old 01-11-2017, 07:58 PM   #28
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Originally Posted by brewstergalVT View Post
Wow, that's great! Thanks for doing the experiment, I look forward to reading your results!!

Well the stir plate starter definitely finished well ahead of the shaken sample by 12-18 hours.
Additionally, the cell counts showed significantly more growth in the stir plated starter.
I let both run for 36 hours then homogenized and pulled a 10ml sample from each. Both samples were equally diluted before counting.
I will admit that 3522 is a highly flocculant strain and may not have been the best choice for this experiment.
Had I let the shaken sample run longer it may have built up a few more cells but it would have never caught up to the stir plate version. When I decant I will check gravity.
If I have more opportunities in the future for further testing I will report back.
I would be curious if one had an oxygen set up placed in the starter and turned on periodically what the results would be. I do this when I make large starters in 5 gallon buckets because I can't get them on a stir plate.
Honestly I think a long slow injection of O2 or periodic injections may be better than a stir plate but I don't have any data to support that.

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Old 01-11-2017, 08:46 PM   #29
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Quote:
Originally Posted by sky4meplease View Post
....
...I think a long slow injection of O2 or periodic injections may be better than a stir plate but I don't have any data to support that.
Braukaiser has looked at this with injection of air into a stirred starter.



Effect of access to air on yeast growth in a stirred starter

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Old 01-12-2017, 02:51 AM   #30
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Thanks Gavin C and sky4meplease for the info. I've already changed my practice a bit to help the yeast based on what both of you have shared. I had been doing my starters in a 2L mason jar fitted with a plastic screw on lid drilled and fitted with a grommet and airlock. The currently growing starter I have covered with a double layer of paper towels (initially sprayed with vodka), secured with a rubber band and a loose cover of aluminum foil (just because I'm scared). Shaking it as often as I can. Thanks again for your help!!

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