5 Gallon Stir Plate

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thargrav

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We just finished designing our 5 gallon stir plate.

That's right, it's 5 GALLONS, not 5 liters.

My motivation? I got tired of high gravity brews stalling so I decided to design something that would keep all of the yeast in suspension.

Anyways, here's a link to the stir plate.
http://towercooler.com/index.php?option=com_content&view=article&id=82&Itemid=97

And here's a link to a YouTube video showing the stir plate tearing up a 2 liter flask of water.


Now I have what seems like a odd request - I already have a couple of people testing these - three including me. I need two more "volunteers". There are no strings attached and I'm not selling you anything. I just need two more people who need a stir plate like this to try them out & report back the good, bad and the ugly. Send me your address and I'll send you one - FREE!!! But I do need you to use it and let me know your honest opinion of the stir plate. You also need to be someone who wants to try a high gravity beer on the stir plate or at least very large starters.
 
Last edited by a moderator:
I'd love to be a tester. I'll pay shipping! I'd tell you high gravity beers are my middle name, but that would make my name crazy long.

Seriously, I'd love to. s
 
Looks like I have three volunteers - emjay needs to contact me. When i responded to your PM I got a error.

Thanks, Tom
 
thargrav said:
Looks like I have three volunteers - emjay needs to contact me. When i responded to your PM I got a error.

Thanks, Tom
Click to expand...

Hey. Not sure why you had problems responding to my PM
 
thargrav said:
We just finished designing our 5 gallon stir plate.

That's right, it's 5 GALLONS, not 5 liters.

My motivation? I got tired of high gravity brews stalling so I decided to design something that would keep all of the yeast in suspension.

Anyways, here's a link to the stir plate.
http://towercooler.com/index.php?option=com_content&view=article&id=82&Itemid=97

And here's a link to a YouTube video showing the stir plate tearing up a 2 liter flask of water.
Video Link: http://www.youtube.com/watch?v=C2BK-F92h9Y

Now I have what seems like a odd request - I already have a couple of people testing these - three including me. I need two more "volunteers". There are no strings attached and I'm not selling you anything. I just need two more people who need a stir plate like this to try them out & report back the good, bad and the ugly. Send me your address and I'll send you one - FREE!!! But I do need you to use it and let me know your honest opinion of the stir plate. You also need to be someone who wants to try a high gravity beer on the stir plate or at least very large starters.
Click to expand...

No PM, guessing I diddnt make the list?
 
That could be awesome for aerating mead. Have you tried testing it with a bucket?
 
This thing is awesome ! I'd love to test it out .. I want to keep 10g batches in suspension for fermenting under pressure in a sanke keg ! I'm a pro photographer and can shoot it in the studio if you like..
 
Yeah but $189 for a stir plate. I mean i get it stir plates are cool, but there is a lot of other stuff I would buy for $189 before I would spend it on a stir plate.

Not to be a buzz kill, just sayin'
 
BBBF said:
That could be awesome for aerating mead. Have you tried testing it with a bucket?
Click to expand...

I spun some water in a bucket and the stir plate was loud, I think the plastic bottom was acting like a speaker cone. The 5 gallon carboy spins quiet. I also do mead and will try a mead batch in a 6 gallon carboy later this year.
 
CidahMastah said:
Yeah but $189 for a stir plate. I mean i get it stir plates are cool, but there is a lot of other stuff I would buy for $189 before I would spend it on a stir plate.

Not to be a buzz kill, just sayin'
Click to expand...

You are right, I have these priced at $189.00 each. If you are doing standard brews or trying to grow a lot of yeast for 10 or 20 gallon batches then there is no reason to own one of these when you can buy a smaller stir plate for 1/2 the cost.

But if you like to do very high gravity brews or mead, and I like to do both, having the ability to keep your yeast in suspension is worth a lot. But is it worth $189.00? I don't know, it all depends on your goals and your finances. I know I've spent many days fussing over a brew trying to get a little more out of my yeast. And BTW, my highest record high gravity brew to date is 22% alcohol.

I also suspect some microbreweries will be interested - many of them use 5 gallon starters.
 
joeybeer said:
This thing is awesome ! I'd love to test it out .. I want to keep 10g batches in suspension for fermenting under pressure in a sanke keg ! I'm a pro photographer and can shoot it in the studio if you like..
Click to expand...

Unfortunately, the container has to be non-metallic in order for the magnets on the stir plate to couple with the stir bar. The spinning magnetic field will induce an electric field in an any metallic container, which disrupts the magnetic connection to the bar. The container has to be glass or plastic.
 
How much of a vortex do you have when there's 5 gallons on there? If it's anything like the 2L it seems like you might be dealing with some oxidation issues...or does the super high gravity negate those kinds of worries?
 
microbusbrewery said:
How much of a vortex do you have when there's 5 gallons on there? If it's anything like the 2L it seems like you might be dealing with some oxidation issues...or does the super high gravity negate those kinds of worries?
Click to expand...

As long as the airlock has a good seal, all of the oxygen in the head-space has either been absorbed at the beginning of fermentation (when oxygenation is a good thing), or has been displaced by CO2 created by active fermentation. The atmosphere in the carboy is inert with CO2.
 
GNBrews said:
Unfortunately, the container has to be non-metallic in order for the magnets on the stir plate to couple with the stir bar. The spinning magnetic field will induce an electric field in an any metallic container, which disrupts the magnetic connection to the bar. The container has to be glass or plastic.
Click to expand...

Follow the link to the article on my www.towercooler.com web site and you will see a picture of a 5 gallon batch. The vortex is very reasonable.

I knew the stir plate would over power the 2 liter flask - what you don't see in the video is before all he11 breaks loose the stir bar opens up a donut shaped hole at the bottom full of air. At that point only the tips of the stir bar are pushing water around.
 
thargrav said:
You are right, I have these priced at $189.00 each. If you are doing standard brews or trying to grow a lot of yeast for 10 or 20 gallon batches then there is no reason to own one of these when you can buy a smaller stir plate for 1/2 the cost.

But if you like to do very high gravity brews or mead, and I like to do both, having the ability to keep your yeast in suspension is worth a lot. But is it worth $189.00? I don't know, it all depends on your goals and your finances. I know I've spent many days fussing over a brew trying to get a little more out of my yeast. And BTW, my highest record high gravity brew to date is 22% alcohol.

I also suspect some microbreweries will be interested - many of them use 5 gallon starters.
Click to expand...

I think for micro brews these make a lot more sense. Don't get me wrong I think your work yields a really nice looking piece of equipment. But as an avid home brewer who doesn't hold his pocket book back for equip, I also wash yeast. Since I do 11G batches (many of them high gravity) I get a lot of yeast after initially building up a starter. I have had great luck with washing yeast for those batches, high gravity or not, running it 3-4 generations and restarting the cycle. So I rarely have to use a starter, since I direct pitch washed yeast.

Just curious, have you ever put a demijohn on that bad boy? I typically only use demijohns for beers.

Again - don't get me wrong, good work on your development. :mug:
 
GNBrews said:
As long as the airlock has a good seal, all of the oxygen in the head-space has either been absorbed at the beginning of fermentation (when oxygenation is a good thing), or has been displaced by CO2 created by active fermentation. The atmosphere in the carboy is inert with CO2.
Click to expand...
That makes sense. Keep us posted. I'm sure everyone has seen them, but BYO magazine and BasicBrewing.com have teamed up for a lot of experiments lately. I think it'd be cool to see an experiment where a 10 gallon batch gets split in half to see the difference between the half fermented on a stir plate and the half fermented without a stir plate (assuming all other conditions are identical).
 
microbusbrewery said:
That makes sense. Keep us posted. I'm sure everyone has seen them, but BYO magazine and BasicBrewing.com have teamed up for a lot of experiments lately. I think it'd be cool to see an experiment where a 10 gallon batch gets split in half to see the difference between the half fermented on a stir plate and the half fermented without a stir plate (assuming all other conditions are identical).
Click to expand...

Im on the list to get one and micro had the same idea i did. Guess ill be extra busy over my vacation at the end of the month. Cant wait to try out the stir plate.

Rock Chalk

Chris
 
For those of you who are going to test one of these - I'm waiting for more motors to come in. Once they are in we will finish assembly and test. It looks like they will be shipping out by Wednesday or Thursday & I'll post another update then since I did not get everyone's email.
 
Great to hear. Out of curiosity, how many test samples are being sent out anyways?
 
For those of you receiving sample stir plates, they will ship tonight. The motors finally came in today.

Also, these will ship with a single 2" stir bar & not 2 like the production stir plates will, but they are samples.

One thing you will notice right away with 5 gallons is you will not be able to turn the speed up past 1/4. But even at 1/4 you will get a larger vortex than you would in a 2 liter starter with another stir plate and all of your yeast will stay in suspension (already verified by me). The reason is - a motor that provides enough torque to spin 5 gallons also provides more than enough torque to pull away from the stir bar at higher speeds.

Thanks again for volunteering to test these and providing feedback. You are welcome to post the results to this board or directly to me.

Tom
 
The stir plates that are going out are shipping to:
Joey
Doug
Chris
Mathew

I'm missing someone. If I promised you a stir plate and your first name was not on this list please PM me!
 
Bugaboo said:
Looks awesome man! I can see the appeal. You could probably wash your clothes with a stirplate that big
Click to expand...

It would create too much resistance for the stir-bar to push through, but that's a very funny thought :D

If anybody stresses out about making sure their priming sugar is evenly dispersed though, I really can't think of a better way!
 
Cant wait. Got plans for a 120min IPA clone, Imperial Stout, and possbly a Quad on steroids.

Rock Chalk

Chris
 
GNBrews said:
As long as the airlock has a good seal, all of the oxygen in the head-space has either been absorbed at the beginning of fermentation (when oxygenation is a good thing), or has been displaced by CO2 created by active fermentation. The atmosphere in the carboy is inert with CO2.
Click to expand...

Hopefully that's the case, and theoretically it seems fine, but I've been doing this long enough to know that the science is often more complicated in reality (eg things get unaccounted for), but the positive pressure should keep oxygen out. There might be a small chance that movement of air caused by the stirring could push out enough air that pressure equilibrium causes a bit of (oxygenated) air to also seep in, but if that's even possibly, it would pretty much have to be through a leak - usually where the bung makes a seal against the neck of the carboy, where the lid makes a seal again the rim of the bucket, where the grommet makes a seal against the lid, or even where the airlock makes a seal against the grommet or bung. But these kind of leaks generally cause the fermentor not to bubble even at the peak activity (although sometimes it just greatly reduces their size and frequency), so with this baby, there might be an actual good reason to be concerned with airlock activity!

Of course, the possibility of that even happening is mere speculation, and even I'm doubtful about it. But it raises another issue that hasn't even been mentioned yet, despite the fact that it could possibly be the biggest benefit of all to fermenting on a stirplate...

The fact that it drives off CO2. Carbon dioxide is bad for yeast. They don't like it at all. And yet, it's generally unavoidable because they produce copious amounts of it. And to make matters worse, the head pressure created by the water column in the airlock allows it to dissolve in even higher concentrations. But the constant agitation should keep the dissolved CO2 to a minimum, and the benefit to this may be even greater than keeping the yeast in suspension. Even more so if you harvest the yeast and use it for many successive generations, making you especially concerned about yeast health/vitality.

I can't wait to split a 10gal batch into 2 in order to compare them! I should probably decide on a style and start creating a recipe soon... something that doesn't require fermentor additions (eg dryhopping, in order to ensure both batches are identical), and is formulated to highlight and emphasize any anticipated differences, such as using a high-flocc'ing yeast strain that drops out of suspension very quickly when it doesn't have the assistance of a stir-plate.
 
emjay said:
Hopefully that's the case, and theoretically it seems fine, but I've been doing this long enough to know that the science is often more complicated in reality (eg things get unaccounted for), but the positive pressure should keep oxygen out. There might be a small chance that movement of air caused by the stirring could push out enough air that pressure equilibrium causes a bit of (oxygenated) air to also seep in, but if that's even possibly, it would pretty much have to be through a leak - usually where the bung makes a seal against the neck of the carboy, where the lid makes a seal again the rim of the bucket, where the grommet makes a seal against the lid, or even where the airlock makes a seal against the grommet or bung. But these kind of leaks generally cause the fermentor not to bubble even at the peak activity (although sometimes it just greatly reduces their size and frequency), so with this baby, there might be an actual good reason to be concerned with airlock activity!

Of course, the possibility of that even happening is mere speculation, and even I'm doubtful about it. But it raises another issue that hasn't even been mentioned yet, despite the fact that it could possibly be the biggest benefit of all to fermenting on a stirplate...

The fact that it drives off CO2. Carbon dioxide is bad for yeast. They don't like it at all. And yet, it's generally unavoidable because they produce copious amounts of it. And to make matters worse, the head pressure created by the water column in the airlock allows it to dissolve in even higher concentrations. But the constant agitation should keep the dissolved CO2 to a minimum, and the benefit to this may be even greater than keeping the yeast in suspension. Even more so if you harvest the yeast and use it for many successive generations, making you especially concerned about yeast health/vitality.

I can't wait to split a 10gal batch into 2 in order to compare them! I should probably decide on a style and start creating a recipe soon... something that doesn't require fermentor additions (eg dryhopping, in order to ensure both batches are identical), and is formulated to highlight and emphasize any anticipated differences, such as using a high-flocc'ing yeast strain that drops out of suspension very quickly when it doesn't have the assistance of a stir-plate.
Click to expand...

Right. Any pinhole will expose the beer to oxygen. Air is 21% oxygen and atmospheric pressure is 14.7PSI. Since there is no oxygen inside the carboy, atmospheric oxygen is now attempting to diffuse, with .21 X 14.7 = ~3PSI of pressure, on all of the outer surfaces of the sealed container. The airlock is keeping that oxygen out. While it's true that CO2 is heavier than air, if you have a leak, that ~3PSI of oxygen will rush in and become part of the gas mixture inside

While CO2 is technically toxic to yeast, having some in solution actually creates a cleaner tasting beer by inhibiting some yeast metabolism. It will definitely be interesting to hear what stir plate fermentations taste like.

There's a thread over in the "General Techniques" section about pressurized fermentation if you want to read more. Also, here's an article from Applied Microbiology and Biotechnology, titled "Effects of CO2 on the formation of flavour volatiles during fermentation with immobilized brewer’s yeast".
 
Tom, USPS was good to me today. I'll plan on doing a starter this week, for a brew Fri-Sun somewhere in there, that we'll keep spinning.

I do wonder, is the plate big enough (wide enough) to safely support a 5g carboy? or would a little time spend in my wood shop for something be a worthwhile investment. Not a knock on design, just trying to overcome that queasy feeling we all get when we think of a brew-in-carboy breaking.

Thoughts?

also, I suppose with the beer in suspension during fermentation, does one need to rack to secondary? or should the plate be put into play FOR secondary? I'm also guessing that a brew spinning will require nothing more than an airlock and that a blow off tube would be unnecessary.
 

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