Friday, March 22, 2013

Low cost sous vide cooker for under 50 Euros

This time I am writing about a private project of mine which is completely different to the IT bushwah you normally find here.

Since some time now, I have been fancying with sous vide cooking (see en.wikipedia.org) and so I was trying to find a way to get it done at home. The main problem is to find an affordable device to control and hold the temperature of the cooking water. My best clue so far was to get an old/used/broken/something laboratory thermostat. But even if you can get your finger on one of those, they are still a bit too expensive and in my opinion also somewhat oversized and bulky. The situation changed when I finally stumbled upon this fine asian fellow on Ebay:

This is a low budget (about 15 Euros) temperature controlling unit able to switch up to 5A at 230V in order to heat (or cool) "something" with any electrical device meeting the specs. You can find a manual explaining the details here which also reveals the official name of the device: "WH7016C Thermostat".

Besides the controller, you need two other main ingredients for a true sous vide cooker: A heater (duh!) and something to circulate the cooking water to maintain an equal temperature distribution within the pan. The heater I use is a 300W travel water boiler which can easily be connected to the relais on the controller by cutting of the power plug and applying some cable end sleeves (to add a bit of professionality to the whole thing).
The white cord goes to the heater and the black one ends with a german "Schuko" power plug for a normal 230V power outlet. The smaller cable on the right belongs to the attached temperature probe. Don't ask me what pins 5 and 6 are for... Secret Chinese stuff, i guess.

These travel heaters can be found on Amazon or Ebay for about 10 to 15 Euros and are quite sufficient to reach and hold the required temperature even in larger pans. 

The third part to be acquired is, as mentioned, something to provide water circulation within the pan. A small aquarium pump suits just fine for this task. For example, the Eheim compact 300 pump is often recommended for this special case and seems to withstand temperatures up to 90 degrees celsius and even above.

This is all you need. Here is a picture of the whole bunch together,  including some reasonable additions:
Nice to have but not required are: A vacuum sealer (You should be able to suck the air out of a freezing bag with your mouth and seal it tight with a clip. But that's not the real deal, is it?), a "LURCH" butan torch to add some roasting flavor to the finished but always a bit pale food and a large 1/2 sized gastronomy container with cover plate to cook in. A normal cooking pot should do just fine, though.

I am really pleased with the outcome of this project. The essentials cost under 50 Euros and the additions around 75. The temperature controller is astonishingly accurate for its price - It keeps the water within 1 degree under the defined target temperature which I scientifically confirmed using another digital thermometer. I was a bit concerned about the heater only having 300 watts but it turned out to be quite enough.

As the parts are in place, the only thing missing now is some basic knowledge. I really, really recommend the excellent A Practical Guide to Sous Vide Cooking by Douglas Baldwin. You can get the document and many translations for free from his website (Scroll down a bit and/or buy the complete book). I love it for giving many (mainly scientific) explanations about how and why sous vide works and what different aspects it has. It provides you with the basic information required to calculate temperatures and cooking times by yourself. This is an important point, because with these low temperatures and possible hygienic dangers I really would not trust any recipe (for time and temperature) found on the internet without questioning.

To finish this post, I'll add some final pictures of my new sous vide cooker in action: