Introduction: Turn a Slow Cooker Into Sous Vide Cooker

Sous Vide cooking is a method of cooking food, sealed in airtight plastic bags, which is then placed in a water bath. The flavour is locked in and its essence is amplified as the food cooks in its own natural juices. It’s convenient because it cooks gently and precisely at its perfect serving temperature, foods cannot overcook, even if you become distracted or get delayed. It saves time and it takes just a few minutes of hands on time to season and vacuum-seal foods.

Having heard my aunt and cousin endlessly raving about Sous Vide cooking I thought I would see what it was all about. After looking into this I found that Sous Vide water bath ovens cost £450 - £1500. Being a student, this was clearly out of my budget! However, I came up with an alternative solution, to turn my slow cooker into a water bath oven.

This Gadget will enable you to cook Sous Vide without modification to your slow cooker, just a plug in and go.

You will need:

  • A slow cooker
  • Vacuum food sealer

It enables me to buy cheap meat which will be delicious and tender due to the cooking process. I can buy reduced meats and prep them and freeze them until needed. The process it safe to cook from frozen.

Step 1: Tools and Materials Needed

Step 2: Cutting the box - cutting the hole for the temperature display

Step 3: Cutting the box - cut out for the gang switch

Step 4: Cutting the box - Drilling cable holes

Step 5: Preparing the wire and cables

Step 6: Assembly - Part 1: wiring the temperature controller

Step 7: Assembly - Part 2: mounting the controller

Step 8: Assembly - Part 3: wiring the Gang plug

Step 9: Assembly - Part 4: final assembly

Step 10: Cooking!

Step 1: Tools and Materials Needed


  • Rotary multi-tool (Dremel) with cutting and sanding attachments.
  • Screwdriver flat head and Philips
  • Wire snips
  • Wire strippers
  • Soldering iron and solder
  • Drill and drill bits (I used 10mm, 7mm and 3.5mm)
  • Safety glasses
  • Chinagraph pencil


  • ABS Project box (£6 from Maplin) - 150*100*60 mm
  • UK Mains 240Volt IEC Plug (£1.59 from eBay)
  • 10 x 25mm SIDE PILOT HOLE WINDOW SUCTION CUPS SUCKERS ( £2.95 from eBay)
  • Single Gang switched wall plug 13 A (£2.09 from Bay)
  • Temperature Controller Thermostat 220V Control Switch ( £8.74 from eBay)
  • Grommets (optional but advisable (price various depending on quantity)
  • Nuts, Bolts and Washers M3.5 (for mounting the gang plug, bolts are usually supplied)

Step 2: Cutting the Box - Cutting the Hole for the Temperature Display

You will need:

  • Temperature controller
  • Chinagraph pencil
  • Dremel with cutting disk and sanding drum

This step will show you how to cut the box in order for all the components to fit onto and into the box.

Cutting out the hole for the temperature display.

  1. The instructions that come with the temperature controller will tell you how large a hole you will need to cut in-order for the display to mount correctly (If this is not the case you will need to measure these dimensions yourself).
  2. Cut a card to these dimensions so you can position where you want to mount the display.
  3. With the use of a chinagraph pencil draw around the card at the desired location.
  4. Using the Dremel and cutting disk cut out the profile
  5. Sand the ragged edges down using the sanding drum attachment on the dremel to allow for a flush fit.

Step 3: Cutting the Box - Cut Out for the Gang Switch

You will need:

  • Wall plug
  • Drill with 3.5mm drill bit

This step is the hardest. I also would advise you to mount the plug 180deg from where i mounted. This is so the cable from the slow cooker dose not interfere with the temperature display.

  1. Position the Gang face down and draw around it with the china graph pencil.
  2. Turn the gang right side up and mark the position for the mounting holes.
  3. Cut out the required area so that the gang will sit flush with the box, making sure that the mounting holes do not get cut out.
  4. Test fit the gang, When/If it fits drill out the holes for mounting (3.5mm Drill usually)

I cheated by taking apart an old gang switch and using it as a template as you can see in the pictures. I would not advise doing this if you plan on using the gang switch again (it is hard to put back together).

Step 4: Cutting the Box - Drilling Cable Holes

You will need:

  • 10mm and 7mm drill bit

The size of hole will be determined by the size of cable you use or the size of grommet that is used. In my case one hole was 10mm (for the mains cable) the other was 7mm (temperature sensor) with grommets.

  1. Locate the position of the holes.
  2. Drill.

Step 5: Preparing the Wire and Cables

You will need:

  • Wire Strippers
  • Wire Cutters
  • Soldering Iron & Solder

This step will show you how to prep the cables and wires prior to connecting all the components together.

1. Using the snips cut the end off the IEC cable as seen in the picture. This end can now be binned.

2. Cut an additional 110mm off the cable.

3. Cut an additional 50mm off the cable.

4. Remove the outer cover from the 50mm cable. Keep the live (brown) and bin the earth and neutral. (see picture)

5. Using wire strippers (I used a Stanley knife) cut 30mm of the outer cover away from all the other ends (x3).

6. Cut the earth wire away from the 110mm.

7. Strip 5-10mm away from all the existing wires using the cable strippers (I used the snips)

8. With the soldering iron tin the ends of all the wires (see picture)

Step 6: Assembly - Part 1: Wiring the Temperature Controller

You will need:

  • Grommets
  • Flathead Screwdriver

This is the first step of assembly.

1. If you are using grommets place them into the drilled holes now.

2. Push the Mains cable and the temperature sensor through the drilled holes.

3. Taking the 110mm Cable connect the Live (brown) to the switch (pin 1) on the temperature controller and connect the neutral to the Power (pin 4).

4. Taking the 50mm Live (brown) wire connect this to the other side of the switch.

5. Now connect the temperature sensor to pins 5 and 6. It does not matter what way round.

See Picture.

6. Now take the mains live (brown) and the 50mm live (connected to pin 2) and connect both to pin 3 together.

See pictures.

Step 7: Assembly - Part 2: Mounting the Controller

Now that all the wiring to the temperature controller is finished it can now be mounted to the box.

1. Place the temperature controller through the cut out hole ensuing the orientation is correct.

2. Slide the mounting tabs down the side of the controller and press the against the inside wall of the ABS box. This will secretly mount the controller in place.

Step 8: Assembly - Part 3: Wiring the Gang Plug

Please note that the picture has an additional Brown (live) wire coming in from the top. This will not be here in this case.

1. Bring the renaming wires through the hole made for the gang.

2. Connect the wires to there corresponding locations on the gang.

Blue, Neutral, N

There will be two wires going in to the gang. The first will come directly from the mains, the second will come from the temperature controller (110mm cable).

Brown, Live, L

There will only be ONE to connect. this will come from the temperature controller (110mm cable)

Green/Yellow, Earth, Ground symbol

There will only be one to connect, this will come from the mains cable.

Step 9: Assembly - Part 4: Final Assembly

You will need:

  • Nuts
  • Bolts
  • Washers

Now that all the wiring has been completed its time to seal the box.

1. Using the nuts, bolts and washers mount the gang plug.

2. Screw the back panel onto the ABS box.

3. Slide the suction cups over the temperature sensor (3 will do the job)


Step 10: Cooking

You will need:

  • Suction cups

1. Using the suction cups position the sensor at the bottom of your slow cooker

2. Plug your slow cooker into the box.

3. Fill the slow cooker pot with water.

4. Turn your slow cooker to HIGH.

5. Set the temperature on the temperature controller (63'C For Rump stake is my favorite).

6. Let the water to heat up to temperature.

7. Place in your chosen meat (every meat has a different temperature, also, rare, medium and well-done all have different temperatures)

8. Cook for required length of time.

9 . Enjoy the most tender meat you will ever have.

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