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stirplate question

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nduetime

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Okay...so I'm in the process of creating my own after reading the couple of posts of others that have show their.

I've been wondering something for a long while about this. Please don't just down my throat too much for it.

The purpose of it is to increase cell count, keeping the yest in suspension and providing it with plenty of oxygen right? The whole time the wort is on the stirplate, it's converting the surgars and producing alcohol, right?

So this all leads me to my stupid question. Why can't we ferment on a stirplate? Would there be any problems with fermenting on a stirplate.

One question would be if a airlock could be attached to the vessel during while on the stirplate?

Pictures I've seen don't show the flask with an airlock attached when in use (of course I haven't seen many pictures stirplates in use with wort in flasks sitting on top, mostly only water).

Let the ripping begin.
 

Zymurgrafi

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Probably would work. The trouble is building a stirplate that big and finding a stir bar that big. I imagine balancing the stirplate would become more of an issue on that scale.

If you have ever listened to the brewing network Sunday session, the guy they call "doc" on there has mentioned he has or is in the process of building such a beast.

Give it a go and then let us know how it works! :D
 
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nduetime

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I have scaled down my batches to 2.5 gallons which is still pretty large I know.

Could one expect to see a decrease in fermentation time? Greater amount of fermentation because of the suspension?
 

mr x

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I used to use a small aquarium pump submerged in a bucket to circulate my turbo yeast mashes. Worked very well. I don't think you want to constantly aerate the wort, just keep the yeast in suspension. I think the pump is easier, but maybe not.
 

Scimmia

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From what I've read, there are different stages that the yeast go through. When they have oxygen, they are mostly using the oxygen and sugar for reproduction. After they're out of oxygen, they really start producing alcohol and CO2.

Not to mention your finished beer would be HORRIBLY oxidated.
 

Scimmia

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Hey, you quoted my horrible grammar before I had a chance to edit! Not fair!
 
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nduetime

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I guess I'm confused. A starter is essentially a very small batch, correct? I understand about the oxidation but why it's it an issue in the starter?
 
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nduetime

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Can oxidation occur below 80*? I would assume yes?
 

Bsquared

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Scimmia said:
From what I've read, there are different stages that the yeast go through. When they have oxygen, they are mostly using the oxygen and sugar for reproduction. After they're out of oxygen, they really start producing alcohol and CO2.

Not to mention your finished beer would be HORRIBLY oxidated.
When cells consume O2 and sugar it is called an aerobic reaction and Glucose is converted to all the way down to CO2 and H2O, producing lots of ATP that the cell uses for energy. This is when the yeast will expand, or rapidly reproduce. ( ~Double every Hour)

When cells lack O2 (as in the fermenter) they run an Anaerobic reaction that is not as efficient as the aerobic reaction, breaking down the glucose to CO2, CH3COH (Ethanol) and H2O, producing only a couple ATP/ Glucose.

because this is vary inefficient yeast will not reproduce in these conditions. The starter is done so you can have the maximum amount of yeast in the fermentation vessel to convert your sugars to Ethanol and CO2, as quickly as possible. If you under pitch then the yeast you pitched will have to do more work, and as they age in unhealthy conditions they can impart off flavors into the beer.

If you do agitate the yeast in the fermenter you will probably have to stop and wait a couple days before racking it to the secondary, but I don't think it is too good of an idea to agitate the yeast cake, its kinda the sewer for the yeast.
 
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