Sous Vide Cooking

Sous Vide & Electricity consumption – Astonishing!

by on Jan.17, 2010, under Equipments & Accessories


There is now some weeks I wanted to verify by myself if a sous vide equipment is more energy efficient than a “traditional” convection oven. Cooking sous vide some kind of meats can take even several days (for example 72 hours pork ribbs at 57°C). What are the electricity costs?

How to proceed to illustrate this point?
My first thought was to compare the quantity of energy used by a convection oven and an immersion circulator (or a PID controller) in order to obtain the same doneness (rosé) on a 1 Kg beef filet.
Therefore I purchased in a do it yourself shop a very cheap appliance (EUR 11) to calculate the quantity of energy used by an electrical appliance (“consomètre” – refer to the picture on the left).
Unfortunately this “consomètre” cannot be plugged to my convection oven (the electrical cables of the oven are directly connected in the wall.  In other word I have no mains where to plug this “consomètre”.

Thus I have decided to restrict my test to the assessment of the amount of energy used during a cooking process of at least 8 hours at 60°C. The final goal is to determine the cost of such cooking process.

I will not spend any time on the scientific explanation between Power and Energy since the purpose of this blog is only cooking. Nevertheless, for those who want to refresh their mind about physics basics I recommend reading this small article.

In order to determine the price of the energy consumption of an immersion circulator during 8 hours at 60°C I took a round pot of 15 liters and filled it with 28°C tap water.

It took 22 minutes for the swid to reach the target temperature of 60°C at full power (2,170 W).

Then the swid was stable very fast (some secondes only). At this stage the total energy consumption was 0.74 KWh which represents 8 cents (in France, 1 KWh = 0.11 €).

During the next 8 minutes the swid was struggling with power variation in the range from 50W to 600W. I would say the average could be in the area of 300W.
After 1 hour (excl. pre heating) the power variation was in the range from 14W to 200 W. At this stage (1:20 hours incl pre heating) the total energy consumption was 1.06 KWh.

Then I covered the tank with a plastic wrap in order to avoid water evaporation and let the swid run for additional 7:25 hours. When I came back in the morning the result was amazing. Power variation was in the range from 11 to 25 W. Total energy consumption was 2.05KWh (8:45 hours incl pre heating).

For France this represents a cost of approx. € 0.22 (0.33$ with currency rate of 1€ = 1.5 $). Astonishing isn’t it?

Jean-François

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8 Comments for this entry

  • Frank Hsu

    It is amazing how much energy you can save if you improve insulation.
    You can try an other experiment with SousVideMagic/Rice cooker, you will be more astonished on how much energy you can save when compared with an immersion circulator method.
    Great experiment!
    Frank

  • Jean-François

    Frank,

    I agree, a rice cooker is definitly better insulated than a pot simply covered with a plastic wrap. Anyway, this test illustrates that the electricity consumption is high during the pre heating phase (same when you are heating water in a pot) and very low energy is needed to stabilize the temparature (the equivalent of 0.33€ per day).

    Jean-François

  • casquette

    Don’t want to be a pest, but I just wanted to let people know
    that I’m starting a blog about cooking, but especially about Sous vide. I’m not trying to hijack people from this one, which I’m reading all the time, just an addition to the Sous vide community. http://www.fiftyfourdegrees.com, it’s in english, but I’ll
    translate in french which can be access through:
    http://www.cinquantequatredegres.com.
    And Jean-Francois, Keep up the good work, I love your blog.

    Merci

  • Jean-François

    Hi Casquette.

    Your blog doesn’t seem ready yet. Keep me informed as soon as it is. Are you French?

    Jean François

  • casquette

    Indeed I am french, but I live and work in London.
    I had some technical issues with WordPress and as I am not a technical guy, I have to wait monday for a friend to help me set it up properly. I will let you know when it’s ready. My goal is to share what I know about sous vide and cooking in general.

  • Jean-François

    Casquettes,

    Did you see the rollover on the sidebar of the blog with the flag? If you click on it you’ll have access to the French part of the blog. Then we could discuss in French.
    Do you have specific skills in sous vide?

    Jean-François

  • casquette

    The site is pretty much up and running I still have a couple of things to learn about Blogging, but it’s readable.

    N.

  • edhan

    A Question -

    Is it safe to vacuum pack meat, freeze it, defrost it in the fridge and then cook it sous vide (while in the same vacuum pack)? Does it increase the risk for botulism poisoning?

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