Using a stir plate can help a yeast starter grow faster and healthier quicker.  Brewing 10 gallons batches can get expensive so I have looked at all kinds of different ways to cut down on ingredients cost.  Using a stir plate along with a yeast starter allows you to purchase one packet of yeast for a standard 10 gallon ale recipes or high gravity brews or even lagers.

Everything in this do it yourself can be purchased at RadioShack or taken from old electronics around the house.  This is a great project to show your wife that the old PC in your closet, shes been trying to throw away for years, was there for a reason.  The stir plate I built was taken from a bunch of different source online so I am not really sure who to credit, regardless here is a stir plate that can be used for brewing that is very cheap, easy to build, quiet and will save you money.

Gather Necessary Equipment

1. Project enclosure box($7 at RS)
2.  4 inch 12 volt DC PC fan (pull out of old PC or buy one online)
3. Rare Earth Magnets (pull off of old hard drive from old PC or buy at RS)
4. Power Supply 12V to 6V DC (old cell phone charger/keyboard/Nintendo or buy one at RS)
5.  Power Switch ($3 at RS)
6. Rheostat/potentiometer 25 Ohm, 3 Watt ($3 at RS)
7. Washer/Screws/Bolts ($2 at Lowes)
8. Strong Glue or Epoxy
9.  Rubber Feet (pull off of old PC or buy at RS)
10. Stir bar, 1-2 inch (order online $6-$8)

Listed below is the equipment I used to build the stir plate.

Project Enclosure Box for Stir Plate

project enclosure box for stir plate

PC Fan for Stir Plate

pc ban used to build stir plate

Hard drive magnets for Stir Plate

hard drive magnets for stir plate

power adapter used for stir plate

power adapter used for stir plate

power switch for stir plate

power switch for stir plate

potentiometer for stir plate


nuts and bolts for stir plate

nuts and bolts for stir plate

Attaching the Magnets

Use a large washer when attaching the magnets to the fan.  This gives the magnets something to hold on it and prevents too much interference on the fan motor.  I used both rare earth magnets out of one hard drive, one magnet was not enough.  If using two magnets stack them on top of each other, I could not get it to work with them separated.  To remove the magnets from the hard drive mount plate, simply wedge a flat head between them and tap it with a hammer.  Center the washer on the fan and use gorilla glue or epoxy to attach it.  I did not glue my magnets down, but it wouldn’t hurt to do so.

mount magnet on fan with washer

mount magnet on fan with washer

Testing the Fan with Magnets

Rather then just jumping in and soldering, I figured it would be a good idea to simply cable it all up and test it out.  To do this I used temporary wires with alligator clips to connect the power supply, power switch, potentiometer and fan.  Make sure the power supply is ALWAYS disconnected while working on the circuit, electronics can be very dangerous so be careful.    Remove the connector on the end of the fan and power supply then strip the wires.  The positive line out of the power supply should go directly to the supply contact on the switch, different switches have different contact layout.  The ground wire form the power supply should go to the fans ground wire, which is usually black.  Next connect the load contact on the  power switch to the center pin of the potentiometer.  Lastly connect the positive line out of the fan to the right most pin on the potentiometer.  Here is a wire diagram of how the circuit should be connected.

initial testing of stir plate

initial testing of stir plate

While testing make sure that the fan is supported by a clamp or something.  Do not hold the container with the stir bar above the fan, this will not work.  The container will need to sit on on the clamp, approximately 1/2 inch from the magnet.  Also make sure you are using a jar/flask/container with a flat bottom, if it is concave/convex it will not work.

Mounting the Fan with Magnets

Alright so the fan/magnets work and the stir bar spins, now lets package everything up so that it looks nice.  First you need to mount the fan to the top of the enclosure box.  To do this clamp the fan to the top of the enclosure and marked the holes to the exact location and drill bit size.

drilling holes to mount fan

drilling holes to mount fan

Mount the fan using 10-32 x 2 screws and bolts.

mount fan assembly on enclosure top

mount fan assembly on enclosure top

Wiring up the Switches

Drill a small hold in the back of the enclosure box and run the power supply cable through it.  Pull it with enough slack to work with then tie it off, so that it cannot be pulled out.  Drill holes in the front of the enclosure to seat the power switch and potentiometer.  Soldered the positive line from the power supply to the power switch.

solder power for a stirplate

solder power for a stir plate

 Next solder the middle pin of the potentiometer to the load contact on the power switch, I used the white wire here.

solder power and potentiometer for stirplate

solder power and potentiometer for stir plate

Wiring up the Fan

The fan has two wires, positive(usually red) and ground(usually black).   Solder the positive line out from the fan to the right most pin on the potentiometer.  Then attach the ground wire out of the fan to the ground wire from the power supply using a standard wire connector.


complete stirplate wiring

complete stir plate wiring

Mount Feet

Attach the new enclosure top with the fan to the enclosure box using the provided screws.  Flip the enclosure over and attach rubber feet, they will really help with vibration.

stirplate with added rubber feet

stir plate with added rubber feet

Flip the enclosure back over, plug it in and place the flask with the stir bar in the center, the magnets should line up.  Place the potentiometer on the lowest setting and power it on.  Gradually increase the speed to create more stir.

final testing of the stirplate

final testing of the stir plate

Here is a video of it in action.

That’s it, go brew more beer!  If you have any comments or questions please post them below.

building a brewing tower

Having a brew tower or brewing structure is really helpful in keeping your brew day consistent, organized and safe.  Unlike the usual step by step instructions on other projects on BrewMoreBeer, I will just explain what went into Black Betty and hopefully that will be enough to inspire you to build something similar.  Like Brutus, Wallace and others before her, a named brew tower is a great way to define a structure for easy reference, so we deemed our structure Black Betty.

black betty brewing tower

Black Betty the Brewing Tower

The brew tower project as a whole cost about $140 in materials and a few nights to put together.  Which is not too bad for a full blown gravity fed all grain brewing tower.   To put things in perspective just a pump alone usually cost around $140.   Black Betty’s components are positioned so that no pumps are necessary, the tower uses gravity to move the beer from one stage to the next.

Materials List with Cost

Steel/Wood Shelving Unit (black friday special at lowes)  $40
Nuts/Bolts/Screws  $25
2x4x8 x 12 of them  $25
Black Grill Paint  $15
Casters (wheels)  $25
PVC (water filter holder)  $2
Stainless Steel  $8

The Components

The left most component in the upper tier is a hot liquor tank burner which is mounted and framed with 2×4 for support and stability.

brew tower top tier

brew tower top tier

To the right of the burner is a heat shroud that was built to protect the mash tun (plastic cooler) from becoming too hot or even melting.  The left side of the heat shroud has a piece of sheet metal to deflect the heat coming off the burner, the right side (facing cooler) has a piece of particle board to act as an insulator.

brew tower heat shroud

brew tower heat shroud


To the far right on the upper tier sits the cooler mash tun.

brew tower mash tun to boil kettle

brew tower mash tun to boil kettle

The lower tier can be thought of in two pieces, the boil area and cool down area.  The left side, boil area, is a burner with stand that has been mounted and framed with 2×4 for support and stability.

brew tower lower tier boil area

brew tower lower tier boil area

The right side, cool down area, is where the carboys sit and wait to be filled with wort.  There is a plate chiller positioned in the middle of the lower tier.  This design allows the wort to flow out of the boil pot through the chiller and down to the carboys.

beer tower lower tier

beer tower lower tier

Other Features

A water filter mount was created to hold our water filter for brewing.  This helps to stablize the filter from falling over and keeps it mounted so that it can fill the hot liquor tank easily.

beer tower water filter mount

beer tower water filter mount

The entire tower is coated in a black grill paint which should have a heat tolerance up to 1200 degrees F.

The tower has wheels that lock on both the upper and lower tiers which allow for mobility and easy storage.

beer tower wheels

beer tower wheels

The upper tier has a shelf for propane tanks, this allows for easy access to the them.

Black Betty the brew tower

gravity fed all grain brewing tower

black betty on brew day

black betty on brew day

Thats about it, if you have any questions or comments about Black Betty or beer towers in general just comment below.