DYI Stirplate Trouble

I have been stuck trouble shooting my Stirplate build. I followed Anthony Lopez cheap and easy stirplate build up the project locater on this site. I attempted using several old cell phone chargers, but they did not provide enough power to get water whirl-pooling. So I realize I need more power.

I went to Radio Shack and they have a ton of options, but I have no idea about this stuff and neither to they. I believe I want an AC to DC power source that can switch voltages from 5V, 7V, 9V and 12V, but I don't even know. They range in price from $20 to $48, so before I shell out the money and splice the cords I want to know I am getting the right thing. If you know of links on ebay or amazon that would be cool too. Thanks

Do you have any surplus stores near you? I was able to fin a 12VDC wall wort for $6.00 at the one by me.

I'll have to look at the local hardware store, but I still need to know exactly what I need to buy.

If you didn't do a speed control knob on your stir plate and want something that can switch voltages then something like this http://www.amazon.com/dp/B0014JUGTQ/?tag=skimlinks_replacement-20 should work, If you look at the larger picture you will notice a slider at the bottom edge where you switch the voltage.

Go to a pawn shop near by, and buy the oldest wireless phone they have - The power supplies were 12v DC, and usually over 1 amp. Plus it shouldn't cost much!

CL might be a good option too.

You don't need a vortex for a stirplate to be effective, all that needs to happen is to have that stirbar spin a bit to keep the starter churned up and get the yeast more in contact with the sugar.

If you've already got that then you're golden, if not then I'd recommend the adjustable wall-wort linked to above.

A 12VDC fan will require DC Voltage. Somewhere between 0 and 13ish volts should work.

Check to see if the fan is turning without the flask. I used a cheap potentiometer on my stirplate and don't even use it. I have a 6V mobile phone charger wired in and the pot is turned all the way down.

The vortex is cool, but you don't need it. Even at a slow speed, the yeast will become suspended, and remain in contact with the wort and the surface to exchange oxygen.

My stirbar is ribbed for my pleasure. That might also help.

I have a 12V power supply and I am thinking it might be too much? I have a 1 1/2" stir bar and for the love of life I cannot get it to spin. When I turn my unit on the thing just jumps around and never spins. I have tried reversing the magnet (the arc shaped one from the inside of a hard drive) and it still jumps. The HD magnet isn't epoxied to the fan in any way, it just sticks to it since the fan itself must be magnetized. Do I need a second potentiometer to reduce the current/speed or should I switch to a 6-9v power cord and see if it does anything?

Have you tried a shorter stir bar. I have the stir plate posted above and it came with a 1" stir bar. It works fine when an I usually make a 1800ml starter.

I bought a longer 1 1/2 stir just to try it and it just jumps around. After make 5 or so starter I realize that I don't need that big of stir bar. It doesn't take much to keep the yeast in suspension.

On my 12V fan I used a 9V power supply and a regulator. This will slow the fan down enough so it doesn't go spinning the magnet off.

Go to goodwill. You can probably buy 10 power supplies for about $3. One of them ought to work. If you spend $50 on a power supply I would just buy a commercial stir plate.

rockytoptim said:

Have you tried a shorter stir bar. I have the stir plate posted above and it came with a 1" stir bar. It works fine when an I usually make a 1800ml starter.

I bought a longer 1 1/2 stir just to try it and it just jumps around. After make 5 or so starter I realize that I don't need that big of stir bar. It doesn't take much to keep the yeast in suspension.

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I haven't tried a shorter bar yet...the one I bought off of E-bay was almost $10 including shipping so I was hoping it would work if I just adjusted the fan/spin rate/magnets. I have a 3000ml erlymeyer flask, so I am also hoping that the weight of the test water isn't a factor

wyzazz said:

You don't need a vortex for a stirplate to be effective, …

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I agree. In fact I would say you DO NOT WANT a deep vortex. Once the yeast get going the wort layer on the bubbles thickens and they do not pop as quick. If you were creating a vortex, you would be sucking air bubbles down into the wort and the container would soon overflow with bubbles.

[Disclaimer: I do not currently have a stir plate. This info comes from using an aquarium pump on a starter. After a few hours, you have to cut it WAY back to almost nothing.]

I guess I am just a simpleton but for about $12 i picked up a laptop cooler with a variable speed fan. Works with just a little dremel work on the fan screen. Just my .02 cents

Beer_Guy said:

I agree. In fact I would say you DO NOT WANT a deep vortex. Once the yeast get going the wort layer on the bubbles thickens and they do not pop as quick. If you were creating a vortex, you would be sucking air bubbles down into the wort and the container would soon overflow with bubbles.

[Disclaimer: I do not currently have a stir plate. This info comes from using an aquarium pump on a starter. After a few hours, you have to cut it WAY back to almost nothing.]

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I agree that a strong vortex is not necessary at all, but it it also won't automatically result in a foam over situation. Use foam control in your starter and you can largely avoid both boil overs when preparing the wort and foam overs when running the stir plate. The foam control also works well when aerating wort in a fermenter. I've never heard of anyone using an aquarium pump to continuously aerate a starter. That's a new one on me. Other than the foaming problem, how well does that work? Can you do this in lieu of using a stir plate?

I've never heard of anyone using an aquarium pump to continuously aerate a starter.

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I do


Cheers,
ClaudiusB

ClaudiusB said:

I do


Cheers,
ClaudiusB

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Does this eliminate the need for a stir plate? Seems it like it would.

As for as a pump eliminating a stir plate. In theory the bubbles keep the yeast moving around, but in my case when I turned it down low enough to prevent a foam over, there was little or no action on the other side of my one gallon jug. But, it was a lot easier than the “Shake when you see it” method.

I will be building a stir plate before my next starter. I may still use the pump for added measure.

PDawg said:

I guess I am just a simpleton but for about $12 i picked up a laptop cooler with a variable speed fan. Works with just a little dremel work on the fan screen. Just my .02 cents

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Cool! I’ll look into that. Thanks. How about a link or some pix?

I am in Afghanistan right now and picked up three of them from a little shop on post. I sent two of them home but i kept one un modified, to uhhh cool my laptop. I can modify it and make a stir bar from an 8 penny nail and heat shrink. I should be able to get a nice pic in a few days of my coffee being stirred by it,,,lol

I like the 8 penny nail trick. My wife wants some of that liquid tool handle coating stuff. I bet that would work too. Thanks again.

ClaudiusB said:

I do


Cheers,
ClaudiusB

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+1 Me too......I have also heard claims that it is better to aerate the starter than the wort.

I don't want to give the wrong impression I have access to a mag particle setup at work. This allows me to magnetize things a nail won't work until its been magnetized.

No problem. As a kid I learned to magnetize a nail by dragging a magnet the same direction down it several times. Just hold one end and work that a while, then reverse the nail AND the magnet and repeat. What you are doing is pulling all the steel molecules North polls in one direction and then all the South poles in the other. It should work. Always did 40+ years ago.

I’ll just cut the head off and grind the ends smooth. Then do that before I coat it.

Originally Posted by Catt22
Does this eliminate the need for a stir plate? Seems it like it would.

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Correct, if done right.

Originally I used an aeration stone with my step up process which created too much foam.
Removed the the stone and used the 1/8" SS pipe, it worked great with or without stir plate.
On the left, pipe with compressed end and two exit holes.
On the right standard aeration stone.

Pipe only and strong air pump


I decided I needed two more stir plates for my incubator, cut the pipe into pieces and of course too short to reach the bottom of the flask.
Now I am back using stir plates and inject the filtered air into the head space of the flask.
The stir plate was running too fast and created the foam showing.


Cheers,
ClaudiusB

I never thought about that. Once the wort is aerated, add yeast and then use larger bubbles to keep the yeast moving. The large bubbles would burst quicker and not cause foam over.

Good thinking.

This might help even more by keeping the wort spinning.