Agitating your home brew

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Agitating your home brew

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jema
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Joined: 28 Oct 2004
Posts: 28111
Location: escaped from Swindon

Posted: Fri Apr 01, 05 7:34 am Post subject: Agitating your home brew

I often sit in my office by my fermenters berating Tony Blair and the state of the nation.... Well i probably do, but seriously folks,

as I have been reaarranging my office space this week my fermenters have been getting a lot of agitation and looking at them this morning they all seem in much finder form that they have been for awhile.
Is this the steadier spring time temps, miserable though the weather has been the last few days, or does a good shake occasionally help them along?

Hedonists

Joined: 13 Jan 2005
Posts: 95
Location: Romford, Essex.

Posted: Fri Apr 01, 05 3:21 pm Post subject:
On some of the beer brewing forums they reccomend giving the contents of a ferment bin a vigorous stir once or twice a day. Apparently this aerates the brew, feeding more oxygen to the yeast. I've certainly noticed that when the fermentation seems to have slowed down a bit, if I give it a good stir and return to it an hour later its picked up no end.

tahir

Joined: 28 Oct 2004
Posts: 45420
Location: Essex

Posted: Fri Apr 01, 05 3:22 pm Post subject:
Mr H has your missus been in to look at those pots yet? If not I'll nip in there on my way home to see if they've got any non ally ones.

jema
Downsizer Moderator

Joined: 28 Oct 2004
Posts: 28111
Location: escaped from Swindon

Posted: Fri Apr 01, 05 3:23 pm Post subject:

Hedonists wrote:

On some of the beer brewing forums they reccomend giving the contents of a ferment bin a vigorous stir once or twice a day. Apparently this aerates the brew, feeding more oxygen to the yeast.

I've certainly noticed that when the fermentation seems to have slowed down a bit, if I give it a good stir and return to it an hour later its picked up no end.

That's the aerobic fermentation stage, where a stir makes perfect sense though. Mine on the other hand are under the air locks.

cab

Joined: 01 Nov 2004
Posts: 32429

Posted: Fri Apr 01, 05 3:35 pm Post subject:

jema wrote:

That's the aerobic fermentation stage, where a stir makes perfect sense though. Mine on the other hand are under the air locks.

Stands to reason that a bit of agitation speeds things up.

Microbiology takes more from chemistry than any other branch of biology. Populations are so large that the kinetics can me more like chemistry than biology. Think of it this way, a yeast cell floats around by brownian motion, but he tends to sink. He eats sugar when he can find it, but he needs traces of other things too. His likelyhood of finding a sugar molecule depends on how much sugar there is, and how much of the medium he travels through.

As the sugar starts to run out (and it's running out fast, a lot of it has gone by the time you're in secondary) he's looking around frantically for sugar. Move him around a lot and you can boost his chances, and your rate of alcohol production can be faster.

But there's a catch; increase his growth rate and you will change his metabolism. Disturb him too much and all his mates who've sank (many of them dead and dying) also join in the action, and what you don't want is for those dying guys to start reproducing, they'll start releasing all manner of bad tasting auto-lysate products.

So a bit of agitation goes a long way, but to be honest in secondary you can rely on brownian forces to do the work for you, that and a bit of gas production.

Agitation later on, when the whole thing is done fermenting but there's gas left in, can be quite useful in speeding up outgassing.

jema
Downsizer Moderator

Joined: 28 Oct 2004
Posts: 28111
Location: escaped from Swindon

Posted: Fri Apr 01, 05 3:38 pm Post subject:
As ever a fantastic explanation Cab Must say that it fits perfectly. All of them in the fermenters under airlock at the moment are probably fill of yeast cells getting a bit desparate for their next meal

Hedonists

Joined: 13 Jan 2005
Posts: 95
Location: Romford, Essex.

Posted: Fri Apr 01, 05 3:50 pm Post subject:

tahir wrote:

Mr H has your missus been in to look at those pots yet? If not I'll nip in there on my way home to see if they've got any non ally ones.

Not as yet, she's been on nights this week. She's intending to pop in one day next week. So if you're eager to get home on a Friday eve, don't worry. If not, then thank you very much thats very kind of you.

tahir

Joined: 28 Oct 2004
Posts: 45420
Location: Essex

Posted: Tue Apr 05, 05 5:12 pm Post subject:
I had a look on my way home Friday and unfortunately they're aluminium and bloody expensive too, the biggest one was £150

jema
Downsizer Moderator

Joined: 28 Oct 2004
Posts: 28111
Location: escaped from Swindon

Posted: Tue Apr 05, 05 6:13 pm Post subject:

tahir wrote:

I had a look on my way home Friday and unfortunately they're aluminium and bloody expensive too, the biggest one was £150

That's useless then

I think I will post something on aluminium pots and pans, I chucked ours about 15 years ago on health scares.

Blue Sky

Joined: 30 Jan 2005
Posts: 7658
Location: France

Posted: Tue Apr 05, 05 7:06 pm Post subject:
I shake my fermenter daily to agitate it. I discovered this by accident much like yourself (Jema) but it works a treat. It seems to keep the fermentation going which allows me to get it into the pressure barrel sooner. It is good to know that this has been discovered by others too tho'. I wouldn't try it with wine though (well actually I did once - it makes an awful mess ).

Treacodactyl
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Joined: 28 Oct 2004
Posts: 25795
Location: Jumping on the bandwagon of opportunism

Posted: Tue Apr 05, 05 7:12 pm Post subject:
So, jema, how much do you have fermenting in your office? Is all that carbon dioxide in your office good for you?

jema
Downsizer Moderator

Joined: 28 Oct 2004
Posts: 28111
Location: escaped from Swindon

Posted: Tue Apr 05, 05 7:15 pm Post subject:

Treacodactyl wrote:

So, jema, how much do you have fermenting in your office? Is all that carbon dioxide in your office good for you?

I have almost seriously wondered, as currently 31 gallons are bubbling away in here, well actually 26 gallons bubbling one is ready for the clearing process to begin.

Another 12 gallons are in the "clearing" room.

Blue Sky

Joined: 30 Jan 2005
Posts: 7658
Location: France

Posted: Tue Apr 05, 05 7:15 pm Post subject:
Mine is in my office also .... best place for it. Once it is bottled it is nicely to hand I have four "DJs" next to me as I type!

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