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General Category => General Homebrew Discussion => Topic started by: Podo on January 12, 2011, 01:14:09 AM

Title: Aerating with a Mix-Stir
Post by: Podo on January 12, 2011, 01:14:09 AM
Hey all.  I recently picked up a mix-stir and was going to start using it to aerate my batches.  Up 'til now, I've been using an aquarium pump and a beer stone, which has worked well if I let it run for while.  My question is, is there a correct length of time to run the mix stir for good aeration?
Title: Re: Aerating with a Mix-Stir
Post by: tomsawyer on January 12, 2011, 01:18:40 AM
I think a couple of minutes where you whip up a nice froth is enough.  You want cavitation so there is air getting down in the liquid.
Title: Re: Aerating with a Mix-Stir
Post by: Kaiser on January 12, 2011, 03:59:14 AM
When I tested this aeration method last I got ~7.5 ppm after 90s and 8.0 ppm after another 60s. You won't get much higher than 8.0 since this the maximum for saturating the wort with O2 from the air. I'll have to repeat this on an upcoming batch but 2 min sounds like a good number.

Kai
Title: Re: Aerating with a Mix-Stir
Post by: tomsawyer on January 12, 2011, 12:37:43 PM
When I tested this aeration method last I got ~7.5 ppm after 90s and 8.0 ppm after another 60s. You won't get much higher than 8.0 since this the maximum for saturating the wort with O2 from the air. I'll have to repeat this on an upcoming batch but 2 min sounds like a good number.

Kai

You might also do a test at different wort temps, I suppose that might make a differenece.
Title: Re: Aerating with a Mix-Stir
Post by: gimmeales on January 12, 2011, 05:14:59 PM
This is good info!  I typically either use dry yeast or olive oil for aeration, but would be nice to have this around especially considering how effective it is!

Curious as to your methods for measuring the O2, Kai - is it with a Dissolved Oxygen meters I hear are so expensive for breweries?
Title: Re: Aerating with a Mix-Stir
Post by: johnf on January 12, 2011, 05:23:44 PM
This is good info!  I typically either use dry yeast or olive oil for aeration, but would be nice to have this around especially considering how effective it is!

Curious as to your methods for measuring the O2, Kai - is it with a Dissolved Oxygen meters I hear are so expensive for breweries?

Handheld dissolved O2 meters with sufficient resolution to measure dissolved oxygen in wort are affordable, subject to your definition of affordable.

Meters suitable to measure dissolved O2 in finished package beer in a brewery QC program are much more expensive.
Title: Re: Aerating with a Mix-Stir
Post by: Pawtucket Patriot on January 12, 2011, 06:33:52 PM
I seem to recall a certain homebrewer whose first name begins with d and ends in y (and has enn the middle) indicate on the NB forum that he aerated with a mix-stir until the fermenter is filled with foam.

In a related question, how does one use a mix-stir? Do you submerge the wings and let the drill run?  Do you agitate the wort where it meets the air in order to encourage oxygen to get into the wort?  I'm picking up one of these in a couple of days and want to figure out how to use it properly first!
Title: Re: Aerating with a Mix-Stir
Post by: denny on January 12, 2011, 07:15:21 PM
I seem to recall a certain homebrewer whose first name begins with d and ends in y (and has enn the middle) indicate on the NB forum that he aerated with a mix-stir until the fermenter is filled with foam.

In a related question, how does one use a mix-stir? Do you submerge the wings and let the drill run?  Do you agitate the wort where it meets the air in order to encourage oxygen to get into the wort?  I'm picking up one of these in a couple of days and want to figure out how to use it properly first!


Hmmmm...who would that be?

Yeah, that's what I do, although if the fermenter isn't full of foam in a couple minutes I call it good.  As to use, I think you're overthinking this.  I just move it up and down through the wort.  Does it matter?  Probably not.
Title: Re: Aerating with a Mix-Stir
Post by: Pawtucket Patriot on January 12, 2011, 07:32:49 PM
As to use, I think you're overthinking this.  I just move it up and down through the wort.  Does it matter?  Probably not.

It certainly wouldn't be the first time!
Title: Re: Aerating with a Mix-Stir
Post by: MDixon on January 12, 2011, 10:07:33 PM
I've said it before and I'll say it again...MixStir ROCKS!
Title: Re: Aerating with a Mix-Stir
Post by: Pawtucket Patriot on January 15, 2011, 05:25:00 PM
My brewing partner used the mix-stir for the first time yesterday and said it worked great. Only issue is that it created so much foam, there wasn't enough room for the 1L yeast starter!  Is there any problem with pitching the yeast and then aerating with the mix-stir?  That would seem to alleviate that "issue."
Title: Re: Aerating with a Mix-Stir
Post by: abraxas on January 15, 2011, 06:49:18 PM
I use 30 seconds or so of oxygen then 30 seconds of mix stir for most beers.  I haven't been able to detect any oxidation and I've had good attenuation/healthy fermentation.  This seems to work for me though its pretty unscientific.
Title: Re: Aerating with a Mix-Stir
Post by: denny on January 15, 2011, 06:49:46 PM
I always aerate after I pitch.  No particular reason, but no reason not to.
Title: Re: Aerating with a Mix-Stir
Post by: tubercle on January 15, 2011, 07:17:49 PM
I always aerate after I pitch.  No particular reason, but no reason not to.


 Don't, because it will make your yeast drunk.

 Well, go ahead ::) they're going to be drunk in a couple of days anyhow :o

 
Title: Re: Aerating with a Mix-Stir
Post by: lonnie mac on January 15, 2011, 07:22:46 PM
I use a paint stirrer. I believe Denny and I talked about this a long time ago. I have been using one ever since!

I use this in the kettle after cooling. Kinda like a super whirlpool and aerate at the same time. Then I let it settle out for an hour or so... Then I transfer to the fermenter. Not sure what everyone is thinking of with the mix stir, probably the plastic one? Myself, I am talking about one of them 4" diameter paint stirrers.

(http://www.screwfix.com/sfd/i/cat/16/p1825516_l.jpg)


Title: Re: Aerating with a Mix-Stir
Post by: denny on January 15, 2011, 07:35:11 PM
Paint stirrer works great.  The only advantage a MixStir has is that it will fit into a carboy.
Title: Re: Aerating with a Mix-Stir
Post by: lonnie mac on January 15, 2011, 07:44:27 PM
Paint stirrer works great.  The only advantage a MixStir has is that it will fit into a carboy.

Carboy? People use them? :)
Title: Re: Aerating with a Mix-Stir
Post by: bluesman on January 15, 2011, 10:53:18 PM
I use the mix-stir with a cordless drill near the bottom of the fermenter and create an intense whirlpool to the point where I'm drawing air into the wort for two minutes. That's my SOP to date which seems to give me pretty good results. I end up with a bucket full of foam. If that's not enough aeration...well I don't know what else to say.  8)