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Stir Plate - How Long to Let Run?

Finn Berger

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OK. Please realize my OP wasn't asking about dry yeast(s). I'm asking about stepping up liquid yeast and reaching a point where too much oxygen is bad (if this is a cause for concern).
No, the dry yeast was brought in by someone else. (But there's no problem using a stir plate with dry yeast, though I think you should give it a few hours before starting the stirrer. Or at the very least let it sit quiet in there for half an hour. Fermentis has found that vigorous stirring right after pitching the dry yeast directly to the wort, is bad. Just to have said that, I mean;).)

As far as my knowledge goes the best practice is to avoid letting the starter spin after the yeast has consumed all the sugars. I'm not at all sure how much it will hurt the yeast if it is fed oxygen after that has occurred, and I don't understand the biochemistry of what then happens. The yeast will go on feeding on the ethanol - that much I know - so the premise is that that is bad. But I'd dearly like to know why. The hurt presumably is that the yeast depletes it's energy stores, and it needs those stores to build sterols and fatty acids, using oxygen, when you pitch it to a new wort. That process is critical to a healthy fermentation, so you want to pitch yeast with good energy stores.

Of that last point I'm fairly certain, at least. But I'm not sure you need to worry much if your starter has been spinning a bit too long. I'm not sure you don't need to, either:).
 

dtapke

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OK. Please realize my OP wasn't asking about dry yeast(s). I'm asking about stepping up liquid yeast and reaching a point where too much oxygen is bad (if this is a cause for concern).
IMO the nuance of difference you will get from letting a plate go for 12-24-48 hours, vs SNS, vs anything will be minimal. Do your best to pitch an appropriate amount of yeast to a properly aerated wort and move on.

My personal thoughts on order of importance
Fermentation temperature
Pitching rate
good, appropriately oxygenated wort
someplace after at least ten other things I can't think of would be this discussion.

I'll gladly do some cell counts and stains on starters that have been spun for 12-24-48-72 hours if anyone is curious... pick a yeast you want to see and the starter profile your curious about and I'll put some under the scope.

There's certainly a place for this type of discussion, but I believe it's far beyond the needs of a home brewer, or even 99% of craft breweries.
 

Finn Berger

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IMO the nuance of difference you will get from letting a plate go for 12-24-48 hours, vs SNS, vs anything will be minimal. Do your best to pitch an appropriate amount of yeast to a properly aerated wort and move on.

My personal thoughts on order of importance
Fermentation temperature
Pitching rate
good, appropriately oxygenated wort
someplace after at least ten other things I can't think of would be this discussion.

I'll gladly do some cell counts and stains on starters that have been spun for 12-24-48-72 hours if anyone is curious... pick a yeast you want to see and the starter profile your curious about and I'll put some under the scope.

There's certainly a place for this type of discussion, but I believe it's far beyond the needs of a home brewer, or even 99% of craft breweries.
I'm missing "yeast health" from that list of priorities. "Pitch rate" must bee seen in connection with the vitality of the yeast you're pitching. And that's why this discussion is very relevant for all kinds of brewers. I don't think you'll find many yeast experts who would disagree with that.

It's kind of you to offer to do that counting, but that's not what this is about, because you can't read the vitality of the yeast when you do that. You can just differentiate between living and dead cells. (I'm definitely not an expert in the field, though:).)

I don't think you can compare the importance of fermentation temperature to the importance of yeast concerns. You need both good fermentation temperature control and the proper amount of good yeast to make good beer. There is an interplay between them, though, which you need to know how to handle. For instance you need to pitch more yeast if you plan to ferment on the cold side.

Pitching rate is of course important. I don't think you should ever underpitch. But 100 billion cells and 100 billion cells are not necessaily the same. One could mean underpitching, the other a perfect pitch. The difference would be made up by the difference in vitality.
 

Finn Berger

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This discussion reminded me of a new and improved stir-plate technology that was discussed in the AHA forum some time back:

--GF
Sorry, I don't see any attempts at documenting the effect of that. The link aim is deleted. Until evidence to the contrary is produced, I remain highly sceptical. To say the least.
 

Oginme

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The link works for me, though if you are not a member of the AHA, you probably cannot reach that forum. The text of the method and post is below:

There is a new method of yeast starter growth that produces healthier, more vigorous yeast than you have ever had before. This method is called Sinusoidal Continuous Amplitude Modulation (SCAM). You may have heard of the Shaken Not Stirred (SNS) method that is considered by some to be superior to the use of stir plates. This new method uses a stir plate, but it is not your father's stir plate! The key to this process is the use of a stir plate which has the stirring velocity and frequency continuously changing in a sinusoidal form, hence the name.

All athletes know that the key to building fitness is repeated cycles of stress and recovery. Too much stress and you just break down, too much recovery and you lose ground. The key is the combination, and that is what this method provides for yeast. Ramping up to a high velocity gets the yeast up and moving vigorously and promotes healthy gas exchange at the surface. Too much spinning can be stressful, though, so this method ramps down the speed to allow the yeast to rest and recover a bit, but before they have a chance to get flabby the velocity starts up again at the start of another cycle.

But wait, there's more! The yeast would soon adapt to a basic sinusoidal modulation, which is easily predictable. To make things more interesting the frequency of the modulation is varied in a way that produces Bessel sidebands that are unprecedented in stir plate history. By modulating the ampltude and frequency with incommensurate frequencies the pattern produced is highly variable and nearly chaotic. The one certainty is that this will produce very robust yeast that can adapt to any wort into which you pitch them. These yeast will never get bored! They are in a continuously-changing environment that is stimulating and challenging but also gives plenty of downtime. Even the strongest Russian Imperial Stout wort will be no match for yeast grown with this method. They will laugh at even the strongest wort and ask for more. You will get the most vigorous and thorough fermentation you have ever seen, regardless of the yeast strain.

Due to the high technology involved in the production of this device, it will not be available for purchase but will be leased to qualifying customers on a first-come, first-served basis. Click here to get on the waiting list now:
https://docs.google.com/document/d/1TGlkcHotmHRPu0BCJaRSyQkbzzaM_-zGexvJmeL7qow/edit?usp=sharing

It is quite all right to be skeptical about the method since the date it was posted corresponds to April Fools Day.
 

Finn Berger

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The link works for me, though if you are not a member of the AHA, you probably cannot reach that forum. The text of the method and post is below:

There is a new method of yeast starter growth that produces healthier, more vigorous yeast than you have ever had before. This method is called Sinusoidal Continuous Amplitude Modulation (SCAM). You may have heard of the Shaken Not Stirred (SNS) method that is considered by some to be superior to the use of stir plates. This new method uses a stir plate, but it is not your father's stir plate! The key to this process is the use of a stir plate which has the stirring velocity and frequency continuously changing in a sinusoidal form, hence the name.

All athletes know that the key to building fitness is repeated cycles of stress and recovery. Too much stress and you just break down, too much recovery and you lose ground. The key is the combination, and that is what this method provides for yeast. Ramping up to a high velocity gets the yeast up and moving vigorously and promotes healthy gas exchange at the surface. Too much spinning can be stressful, though, so this method ramps down the speed to allow the yeast to rest and recover a bit, but before they have a chance to get flabby the velocity starts up again at the start of another cycle.

But wait, there's more! The yeast would soon adapt to a basic sinusoidal modulation, which is easily predictable. To make things more interesting the frequency of the modulation is varied in a way that produces Bessel sidebands that are unprecedented in stir plate history. By modulating the ampltude and frequency with incommensurate frequencies the pattern produced is highly variable and nearly chaotic. The one certainty is that this will produce very robust yeast that can adapt to any wort into which you pitch them. These yeast will never get bored! They are in a continuously-changing environment that is stimulating and challenging but also gives plenty of downtime. Even the strongest Russian Imperial Stout wort will be no match for yeast grown with this method. They will laugh at even the strongest wort and ask for more. You will get the most vigorous and thorough fermentation you have ever seen, regardless of the yeast strain.

Due to the high technology involved in the production of this device, it will not be available for purchase but will be leased to qualifying customers on a first-come, first-served basis. Click here to get on the waiting list now:
https://docs.google.com/document/d/1TGlkcHotmHRPu0BCJaRSyQkbzzaM_-zGexvJmeL7qow/edit?usp=sharing

It is quite all right to be skeptical about the method since the date it was posted corresponds to April Fools Day.
There's nothing in there that supports the claims made. And the "All athletes know" is highly suspicious. Why should training practices that work for athletes have any bearing on growing healthy yeast?

No, this is first of may, definitely:). Nice try, though;).
 

Oginme

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There's nothing in there that supports the claims made. And the "All athletes know" is highly suspicious. Why should training practices that work for athletes have any bearing on growing healthy yeast?

No, this is first of may, definitely:). Nice try, though;).
The post was the last day of March, right before April 1st which is April Fools Day in the US.

The point is that the posting is satire, making the method appear to be scientifically based by the comparison to athletic training. Take it for what it is and don't read too much into it.
 

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GigaFemto

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Yes, the post was satire. I took it to be poking fun at people who are obsessed with yeast health, and those who take anthropomorphic approaches. I know what health is for a human, but when people talk about "yeast health" I am not sure exactly what they mean.
 

Finn Berger

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The post was the last day of March, right before April 1st which is April Fools Day in the US.

The point is that the posting is satire, making the method appear to be scientifically based by the comparison to athletic training. Take it for what it is and don't read too much into it.
April, of course - it's the same day in Norway:). Slip of the keyboard.

A nice piece of satire. But I don't think it hits the discussion here - if that was the intention.
Yes, the post was satire. I took it to be poking fun at people who are obsessed with yeast health, and those who take anthropomorphic approaches. I know what health is for a human, but when people talk about "yeast health" I am not sure exactly what they mean.
Where do you draw the line between "a healthy interest in yeast health" and "an obsession with yest health":)? You can't mean that all interest in yeast health is obsessive?

I am not sure exactly what health in a human means, either. I think there are quite a few definitions around, including the one that WHO uses. But I guess this will do for yeast: "A healthy yeast cell is a yeast cell that is optimally equipped to do what the brewer wants it to do":). And if being concerned about having yeast that fits that description is being obsessed with yeast health, then I plead guilty.

So much for semantics. I prefer discussing facts.
 

Finn Berger

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Geez... my OP has gone WAY OFF TOPIC.
Somewhat, yes. But to return to your original question, your premise was that the oxygen the stir plate supplies at some point perhaps might turn from being good for the yeast to being bad. Your spesific question was then that if so, at what point did that happen.

My answer is that your supposition is correct; oxygen in a starter may turn harmful, and that happens if you go on supplying it after the yeast has consumed all the fermentable sugars in the starter. Then you are left with the problem of identifying that event, which is actually not very easy to solve. Others seem to think continued oxygen supply doesn't matter, either because oxygen isn't harmful after the sugars are consumed, or because yeast health is not very important.

As you can see, your specific question must lead to a discussion about the premise you are basing it on. And that happened, which I don't see as getting off topic. But then that discussion was sidetracked by the introduction of that piece of satire, and that was not so good. We should stick to discussing facts, not resorting to rhetoric.

So if anything is unclear about the facts - and it always is when discussing brewing topics:) - lets continue discussing them.



We probably all know oxygen is OK at certain points and BAD at other points in brewing. What about a stir plate? How long is a good/safe time to let the stir plate run without introducing unwanted oxygen? I ask as, basically, a starter is a smaller volume brew.
 

Finn Berger

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@KB By the way, when you write that "basically, a starter is a smaller volume brew", I don't quite agree. I'm sure you know, but still: We make starters to make more yeast, and we start brews to make (more:)) beer. And what's bad in a brew need not be so in a starter.

When we make a starter we are on the side of the yeast, and do whatever we can to make it thrive and multiply. A starter should be yeast heaven, and we the servants. In a beer brew it's the reverse; we use the yeast for our own purposes - though we should act as good employers and not make our employees suffer. If you want your employees to do a good job, you should treat them with respect - but they still have to do what they are told. (But if you demand too much of them, and don't give them what they need, they might well go on strike. And the blame will be on you.:))

This means that it's not a sign that we have done something wrong if the starter beer doesn't taste or smell like an awardwinning beer. Probably it's rather a bad sign if it does:). We let the yeast have it nice and warm, and we give it all the oxygen it wants (or we try to), and both tend to produce off flavors. But the yeasties love us.
 
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Brew Bama

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Other than the fact that I’ve had mail order yeast arrive one too many times DOA, all this stir plate/starter/shear/blah/blah/blah is the reason I pitch a healthy dose of dry yeast as the fermenter is filling per the mfr recommendation. It eliminates all the “yeah …but” that is associated with starters.
 

Finn Berger

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Other than the fact that I’ve had mail order yeast arrive one too many times DOA, all this stir plate/starter/shear/blah/blah/blah is the reason I pitch a healthy dose of dry yeast as the fermenter is filling per the mfr recommendation. It eliminates all the “yeah …but” that is associated with starters.
Modern dry yeast is great stuff, and very simple to use, so there's no reason not to use it. But still you've got a lot more to chose from if you opt for fresh yeast.

I use both, but for me that has got nothing to do with the starter question. Starters are a way to keep a yeast strain going. When I've made a starter I save a small sample to use for a new starter further down the road. I do that with both originally dry and fresh yeast. But I always have some dry yeast in the fridge in case the urge to brew suddenly hits me from behind and throws me into the brewery:).

I can't see why the fact that there are different opinions about the right way to go about using a starter should bother you. Just decide what you think is best way, and if that way works for you ... well, where is the problem?

Starters are not the only topic that gives rise to discussions in the field of brewing, and you can't avoid making a lot of descisions about questions which have no definite answers when you are brewing. That's part of the fun, I think:).

I'm not on any crusade to make people do what I think is best. I definitely think people should do what they think is best - at least when it comes to brewing, where it can hardly harm others if they are wrong. But I also think discussions are good - at least as long as the decencies of debate are preserved.
 

Brew Bama

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It doesn’t bother me at all. Anyone can do any they want with their beer. I just simply gave my reason to eliminate starters from my brewery. If someone else wants to use a stir plate, a SnS starter, no starter at all, or any other technique or process that’s their prerogative.
 

Finn Berger

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It doesn’t bother me at all. Anyone can do any they want with their beer. I just simply gave my reason to eliminate starters from my brewery. If someone else wants to use a stir plate, a SnS starter, no starter at all, or any other technique or process that’s their prerogative.
You just said that the discusssion was why you preferred dry yeast: "all this stir plate/starter/shear/blah/blah/blah is the reason I pitch a healthy dose of dry yeast".

I don't care what you do in your brewery. But I do care about keeping disussions tidy. I wrote what I did as an answer to what you actually wrote. If the "stir plate/starter/shear/blah/blah/blah" doesn't bother you at all, what did you mean by what you wrote?
 

BOB357

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After being admonished for a statement made in jest early on in this thread, I've just watched things progress, hoping you might realize that you are not part of the consensus. Unfortunately, this didn't happen. While most of the people contributing to this thread are interested in giving good advice based on things that work for them, it appears that you fail to recognize that your way is not the only way to acheive great results. I've been brewing for close to 15 years now and have tried many ways of managing yeasts, among other things. I, as many others, have found what works best for me. People who haven't should be allowed to see more than one way of doing things and decide what works best for them. These forums are supposed to provide an environment that promotes a mutual learning and sharing experience. Please respect this and also the people who disagree with you.
 

Finn Berger

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After being admonished for a statement made in jest early on in this thread, I've just watched things progress, hoping you might realize that you are not part of the consensus. Unfortunately, this didn't happen. While most of the people contributing to this thread are interested in giving good advice based on things that work for them, it appears that you fail to recognize that your way is not the only way to acheive great results. I've been brewing for close to 15 years now and have tried many ways of managing yeasts, among other things. I, as many others, have found what works best for me. People who haven't should be allowed to see more than one way of doing things and decide what works best for them. These forums are supposed to provide an environment that promotes a mutual learning and sharing experience. Please respect this and also the people who disagree with you.
Would you be as kind as to state where I did not not respect the opinions of others?

Yes, I have an opinion about how to go about making a good starter, but I'm not saying I know it's the only way. But what's wrong about presenting the arguments in favor of my opinion - which is what I'm doing. And if you can tell me why I am wrong, I'm perfectly willing to change that opinion. Believe me, my opinions today about many issues are not the ones I held a few years ago.

BUT: There's one kind of argument I'm not accepting, and that is anecdotal evidence. If someone tells me something has to be true because that's what he or she has experienced, that just is not evidence. You may be very happy with your way of doing something, but that's no reason for me to accept that that is a good way. I'm not saying I know you're wrong. I'm not bothered by you not changing your ways because I think they're wrong. But I can't see why it should bother you that I don't accept your experience as evidence.
 
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