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Author Topic: Shaken, not Stirred: The Stir Plate Myth Buster  (Read 8373 times)

Offline miha

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Re: Shaken, not Stirred: The Stir Plate Myth Buster
« Reply #90 on: January 23, 2023, 08:43:27 am »
SNS is not about cell count, so comparing it in that regard is apples and oranges

What about viability?

Offline denny

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Re: Shaken, not Stirred: The Stir Plate Myth Buster
« Reply #91 on: January 23, 2023, 09:07:44 am »
SNS is not about cell count, so comparing it in that regard is apples and oranges

What about viability?

My personal experience is that viability of SNS exceeds that of stir plate yeast. This is an observation based on experience.
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Offline ynotbrusum

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Re: Shaken, not Stirred: The Stir Plate Myth Buster
« Reply #92 on: January 23, 2023, 10:30:16 am »
+1.  If you can time the SNS high krausen relatively close, it will take off like a rocket, in my experience.  Lately I have brewed back to back batches with an immediate re-pitch from batch to batch and I have had wonderful results in terms of viability.  Again, just my experience.  It helps if you brew frequently enough to harvest and re-pitch within a couple of hours.
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Offline jeffy

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Re: Shaken, not Stirred: The Stir Plate Myth Buster
« Reply #93 on: January 23, 2023, 10:55:14 am »
In my opinion, if you are pitching the entire starter at high kreusen it doesn't matter how you got there, whether you oxygenated it via stir plate or by shaking the heck out of it.  In your case it seems your method saves a step, but for people without a stir plate, shaking saves a step.
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Offline miha

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Re: Shaken, not Stirred: The Stir Plate Myth Buster
« Reply #94 on: January 23, 2023, 11:13:24 am »
If I'll have some time on my hands, I might compare cell count and viability of yeast starter done on stir plate on high speed vs SNS. I'm interested if stir plate actually decreases viability in my case via shear stress.

I agree that reusing yeast from previous batch is great - my usual procedure is to brew a batch and when done, do two or three with the cake straight away (and still discard some of the yeast - easy to overpitch this way).

Offline ynotbrusum

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Re: Shaken, not Stirred: The Stir Plate Myth Buster
« Reply #95 on: January 23, 2023, 11:40:02 am »
If I'll have some time on my hands, I might compare cell count and viability of yeast starter done on stir plate on high speed vs SNS. I'm interested if stir plate actually decreases viability in my case via shear stress.

I agree that reusing yeast from previous batch is great - my usual procedure is to brew a batch and when done, do two or three with the cake straight away (and still discard some of the yeast - easy to overpitch this way).

For sure the re-pitch is not on a whole cake.  Growth is important to yeast vitality, I believe.  I use a stainless ladle that holds about 150 ml and I base re-pitch usage on the volume of wort to be fermented (typically a five gallon or a ten gallon batch size) and the type of beer to be made (5 gallon lager batches get about 4-6 ladles full of slurry; ales get about 2-3 ladles).  These are for generally fairly low gravity beers...
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Offline denny

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Re: Shaken, not Stirred: The Stir Plate Myth Buster
« Reply #96 on: January 23, 2023, 11:43:31 am »
If I'll have some time on my hands, I might compare cell count and viability of yeast starter done on stir plate on high speed vs SNS. I'm interested if stir plate actually decreases viability in my case via shear stress.

I agree that reusing yeast from previous batch is great - my usual procedure is to brew a batch and when done, do two or three with the cake straight away (and still discard some of the yeast - easy to overpitch this way).

Again, forget about cell count with SNS. It's a different theory
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Offline kpfoleyjr

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Re: Shaken, not Stirred: The Stir Plate Myth Buster
« Reply #97 on: January 23, 2023, 03:03:10 pm »
I tried SNS a few times and my only problem was that I had a hard time finding high Krausen by observation.  The batches came out okay with my guess at high Krausen, so I can't knock SNS - I just wanted to find a better way to detect high Krausen in the starter than looking at it. 

Since the SNS experiments, I went back to the stir plate and I place an S-airlock on the Erlenmeyer flask, and watch for a peak in bubbling in the starter, which I take for high Krausen. At that point, I stop the stir plate, remove the airlock and cover the top of the flask with aluminum foil, and then place it in the refrigerator to retard any further growth.  I take the starter out of the refrigerator at the beginning of brew day and let it rise to room temperature while I'm brewing.  I then remove the excess liquid, add some of the wort from my batch, swirl the liquid to get the yeast cake off of the bottom and into suspension, and then pitch it at proper wort temperature. 

I suppose that I could still do SNS, carefully shaking the flask with an S-airlock in place, and watch for a peak in bubbling, but I haven't tried that yet. I might try that some day - but for now, this works for me. The thing I want to do is detect high Krausen better than by just looking at it, and the airlock does that for me.

Offline Richard

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Re: Shaken, not Stirred: The Stir Plate Myth Buster
« Reply #98 on: January 23, 2023, 07:34:25 pm »
I was skeptical that the SNS method could provide enough oxygen for the yeast to make adequate reserves to ferment a high-gravity wort, but I am now convinced. I just finished a stout that started at 1.092 and finished at 1.022 (76% attenuation). I used a standard 1-liter SNS starter of WY1728. I have made enough SNS starters now to be able to time them out pretty well, and at the time of pitching this one foamed and off-gassed like crazy if it was agitated at all. In the past I have added extra oxygen to beers like this, sometimes adding oxygen 18 hours or so after pitching to make sure the yeast had what they needed. In this case I did nothing except pitch the SNS starter and it fermented as well as any other batch of this beer.
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Offline denny

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Re: Shaken, not Stirred: The Stir Plate Myth Buster
« Reply #99 on: January 24, 2023, 08:04:27 am »
I tried SNS a few times and my only problem was that I had a hard time finding high Krausen by observation.  The batches came out okay with my guess at high Krausen, so I can't knock SNS - I just wanted to find a better way to detect high Krausen in the starter than looking at it. 

Since the SNS experiments, I went back to the stir plate and I place an S-airlock on the Erlenmeyer flask, and watch for a peak in bubbling in the starter, which I take for high Krausen. At that point, I stop the stir plate, remove the airlock and cover the top of the flask with aluminum foil, and then place it in the refrigerator to retard any further growth.  I take the starter out of the refrigerator at the beginning of brew day and let it rise to room temperature while I'm brewing.  I then remove the excess liquid, add some of the wort from my batch, swirl the liquid to get the yeast cake off of the bottom and into suspension, and then pitch it at proper wort temperature. 

I suppose that I could still do SNS, carefully shaking the flask with an S-airlock in place, and watch for a peak in bubbling, but I haven't tried that yet. I might try that some day - but for now, this works for me. The thing I want to do is detect high Krausen better than by just looking at it, and the airlock does that for me.

I have found that like many things in homebrewing, close enough is good enough. If I miss high krausen by a few hours or a day, it seems to make no difference.
Life begins at 60.....1.060, that is!

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Offline kpfoleyjr

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Re: Shaken, not Stirred: The Stir Plate Myth Buster
« Reply #100 on: January 24, 2023, 09:17:01 am »
Sorry, Denny - I guess my Engineer disease has carried on into my hobby.  Close enough just isn’t good enough.

Offline denny

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Re: Shaken, not Stirred: The Stir Plate Myth Buster
« Reply #101 on: January 24, 2023, 09:27:31 am »
Sorry, Denny - I guess my Engineer disease has carried on into my hobby.  Close enough just isn’t good enough.

I am an engineer also, and I assure you that for homebrewing it is. But it's your hobby...you can choose to do it however you like. My approach is to eliminate things that I haven't found to make a difference.
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Offline fredthecat

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Re: Shaken, not Stirred: The Stir Plate Myth Buster
« Reply #102 on: January 24, 2023, 02:18:12 pm »
i just did a SNS, and while i wasnt super strict about hitting the right time, i estimated about 60 hours after adding the wlp yeast to the starter wort. it was very turbid when i pitched it into the main wort. does that sound about right?

Offline denny

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Re: Shaken, not Stirred: The Stir Plate Myth Buster
« Reply #103 on: January 24, 2023, 03:08:38 pm »
i just did a SNS, and while i wasnt super strict about hitting the right time, i estimated about 60 hours after adding the wlp yeast to the starter wort. it was very turbid when i pitched it into the main wort. does that sound about right?

Hard to say, but probably.
Life begins at 60.....1.060, that is!

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Offline Richard

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Re: Shaken, not Stirred: The Stir Plate Myth Buster
« Reply #104 on: January 24, 2023, 10:58:22 pm »
The original instructions say that high krausen (defined as maximum cell density, not maximum CO2 production) is usually reached 12-18 hours after pitching the yeast into the shaken starter wort. That can be slowed down by lower temperatures, but 60 hours seems way too long.
Original Gravity - that would be Newton's