Magnetic stirring throughout fermentation...

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Grainer

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Has anyone tried this? Interested.. may be a good way to finish big beers off quicker and get a few more points! Yes i have a commercial medical stir plate
 

warra48

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Is there a potential problem with oxidation ? Starter beers end up quite oxidised, hence I pour off the beer from the yeast I've grown.

Don't know the answer, but someone wiser than me may have an answer.
 

barls

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has been previously discussed and i think it was under full batch stirring
 

Grainer

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No oxidation as you would not introduce oxygen
 

RdeVjun

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I believe it would introduce oxygen. Agitation does just that, it's one of the objectives of a stir plate AFAIK.
 

Grainer

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If it is already under a blanket of CO2 in the fermenter and no oxygen due tot he air lock, I don't understand how O2 can be introduced into there fermenter .. it is a closed system??
 

Black n Tan

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I have thought about this and agree that it is worth a go. If you maintain the airlock then oxygen shouldn't be a big issue, me thinks. However, I wonder why commercial brewers use beechwood to increase the yeast contact during lagering rather than a stirrer? Love to hear how it goes.
 

dr K

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I tried something similar some years ago with SS 22l kegs, sealed and manually blowing off morning and evening (in a controlled temp enviroment).
It did not hurt (the beer and I did a few times), cannot say that it had better results than just , well, fermenting.
Commercially with big top croppers you might (might) see a Burton Union or a Yorkshire square but to take the active yeast sunning it on the top and put em back to work downstairs, which is quite different from agitating trub and such from the bottom.

K
 

MHB

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Black n Tan said:
I have thought about this and agree that it is worth a go. If you maintain the airlock then oxygen shouldn't be a big issue, me thinks. However, I wonder why commercial brewers use beechwood to increase the yeast contact during lagering rather than a stirrer? Love to hear how it goes.
I think there is only one commercial brewer that does that, and they make one of the worst beers in the world - not exactly a recommendation.
Mark
 

Black n Tan

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MHB said:
I think there is only one commercial brewer that does that, and they make one of the worst beers in the world - not exactly a recommendation.
Mark
I should have said 'some'; but really just one? How many use stirring?
 

MHB

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None, in lagering that I know of. I think we are actually talking about keeping yeast roused during primary fermentation. Some very flocculent yeast (best known being Yorkies) can fall out at the drop of a hat, there have been several different solutions including the famous Burton Union and Yorkshire once were square, now round and stainless (mostly) but do the same job of keeping the yeast in suspension.

I will admit to having perched a demijohn of Yorkie on a stir-plate, hooked up to a timer so that it came on for a couple of minutes every half hour. It worked well enough, but so did giving the demijohn with the other half a swirl a couple of times a day. Once FG is reached let it settle, with 1469 in a finished beer you can watch it drop.

Haven't done more than a little quite slow stirring of the primary, from reading more aggressive stirring of both primary and secondary has been experimented with, the results being less than satisfactory, either the beer over attenuates or some unexpected flavours crop up.

Time and patience appear to be the best way to brew.
Mark
 

klangers

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There is a product, sold by APV I believe, for commercial brewing but the trademark/name escapes me just now. It is an external heat exchanger and recirculation pump system coupled to a submersed jet which rotates around in the fermenter. The ferment is recirculated by the pump through the heat exchanger and then out the jets. Controls temperature and agitates the fermentation to keep yeast suspended.

It's a completely valid method - for decreasing your fermentation time and energy bills. Commercial brewers are more interested in this as it frees up tanks faster. As MHB said it might not do much (or anything) for your flavour.
 

wessmith

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Many years back, I had the opportunity to talk to one of the "old school" CUB brewers who was then in his late '80s. My reason for contacting the gentlemen was to try and get an idea of the type of malts and brewing techniques that were used in the pre-war era. One of his personal achievements in a long brewing career was the introduction of a much faster fermentation cycle which used continuous agitation in the fermenter. Apparently the process was fully implemented by CUB in the early 1970's and it did indeed speed up the brewing cycle (then about 48 hours as I recall) but is not used today. Unfortunately that was the only real info I got from the conversation and did not find out much about malts and brewing techniques.

Wes
 

mr_wibble

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I went to a micro in the UK (somewhere near Leicester) last year.

On the tour they had a big square (open-top) fermenter, I guess roughly 3 metres cubed.
As the guy was explaining, a pump started. It was pulling the beer from the bottom of the fermenter and streaming it (through the air) back onto the top of the beer.
They explained that this pump activated periodically to rouse the yeast.
 

MastersBrewery

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So my take on this would be a larger stir plate and bar with intermitent control, and possibly varried speed through each activation. Maybe kicking in every 2-3 hours for 3 or 4 minutes would do the job. Hmm wonder if Michael Burton has some time to dev another stir plate for us.
 

michaeld16

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MastersBrewery said:
So my take on this would be a larger stir plate and bar with intermitent control, and possibly varried speed through each activation. Maybe kicking in every 2-3 hours for 3 or 4 minutes would do the job. Hmm wonder if Michael Burton has some time to dev another stir plate for us.
One this size should do the homebrewer. Heated of course.

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MHB

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Slower - stirred not frappe!
Mark
 
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