Sous Vide Cooking

Digital thermometer with a penetration thermocouple probe – Test for sous vide purpose

by on Feb.09, 2010, under Equipments & Accessories

A month ago I decided to purchase a digital thermomether with a penetration probe. I had a chock when looking at prices  on internet. Price for such thermometer is usually in the range from EUR 200 to EUR 400.
Then, when I saw the Thermowoks onlineshop proposing a similarly equipment for approx. USD 110 incl. shipping to Europe…I decided very fast to make a try.

The overall price was :

  • MTC, Mini Handheld Thermocouple Meter, Type K : USD 43.
  • K Type Fast Response Meat Needle Probe Fitted into MPK ANSI Plug : USD 30.
  • Coiled Lead Type K Extension Wire 2 Meter Plug to Socket Ansi Colour Yellow (627-741): USD 19.
  • Shipping cost to Europe: approx. USD 20.

Total: USD 110.

My worry was to determine how good this thermometer is. Was it well calibrated? I asked a friend of mine if he could find a precision thermometer in order to compare its precision to the Thermoworks one.  Thanks to Bertrand.L I could find someone borrowing me the GMH-3710. He told me he purchased it here for approx?  EUR 220 excl. VAT and shipping costs. This is 3 times the price I purchased mine!

I red on internet that temperature accuracy depends of the temperature. In other words, the higher the temperature is,  the bigger the risk of inaccuracy could appear.

For the purpose of my test I tried with both the thermomethers to assess the temperature of an apple, a glass of water containeing water at 46°C and 79°C.

Above a picture of the GMH-3710

My test with an apple that was laying around in kitchen was excellent. The difference in temperature between the 2 thermometers was in the range from 0.1°C to 0.2°C only. Therefore the inside temperature of the apple was approx. 21.5°C.

The test with the 46°C water was also good with a difference of maximum 0.3°C.

I also made the test with a glass of water at 79°C. The difference of temperature was in the range from 0.3°C to 0.4°C.

To sum up : The Thermoworks digital thermometer seems to work very well and is price competitive. I am in a hurry to try it while cooking sous vide!

Jean-François

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8 Comments for this entry

  • Einar

    Thank you for taking the time to do this test, Jean-Francois. I ordered very similar equipment a couple of weeks ago: The same meter, but with the THS-113-181 miniature needle probe. Thanks to your results, I can trust my readings to well below 0.5C in the regions we normally operate for sous vide.

    Now I just need to get some foam tape. Any idea where I may get it? Cuisinetechnology.com sells for $22 for 0.9m. Any better?

    Also: Does the probe itself feel almost too thin so you’re afraid to bend or break it, or does it feel strong and rigid? Part of the reason I got the mini-probe was that I didn’t want a very long and thin probe – 5cm is enough for all SV-needs.

  • Jean-François

    Hi Einar,

    You are welcome.
    I purchased the THS 113-151 probe because I was scarred the THS 113 181 would be too short. I think you are right, 5 cm should be enough. I am also starting to regret not having purchased the THS 113 181 because the THS 113-151 seems not to be water proof…
    Regarding foam I used to purchase some months ago Turbigomme on this site http://www.machine-sous-vide.net/turbigomme-mousse-noire-le-metre-xml-203_227-696.html

    The price is very competitive EUR 3 per meter excl. VAT and Shipping.

    Jean-François

  • Einar

    Wow, a shop dedicated to sous-vide? I love it :)

  • casquette

    Hey Jean-Francois, i Bought a thermocouple through Ebay
    this one:
    http://cgi.ebay.co.uk/2-K-Type-Digital-Thermometer-
    w-Thermocouple-Sensors_W0QQitemZ330365024997QQcmdZViewItemQQptZUK_BOI_Electrical_Test_Measurement_Equipment_ET?hash=item4ceb4a3ae5#shId
    I wasn’t sure it would work well, but it was $13.90+Shipping which ended up being around $20 total. I didn’t buy the hypodermic probe yet. I will go and buy a proper one (around 120 euros) But i tested with the probes given with it and it seemed to be very accurate. Given the price I don’t think that it will last long, but it’s just $20 it was worth a try.

  • casquette

    Sorry for the long and broken link.

  • Frank Hsu

    The industry needs a better way to sense core temperature. “Piercing through” method is very inaccurate way to measure core temperature even with a very accurate sensor probe. One can never know precisely what the core temperature really is. That’s why most professionals do away with the “piercing” technique and have adopted the “temperature and time table” approach. Many thanks to Nathan and Douglas!
    But this technique is not based on actual measurements.
    Sous vide cooking is “core temperature” centric whereas time should only play second fiddles to ensure food safety and tenderness requirements are met.
    I am calling for new ideas on how to sense core temperature. Any takers?

  • Casquette

    I don’t know, I with Goussault when he says that you don’t need to probe
    the meat unless you’re using the High/low method where you cook with higher
    liquid temperature and stop the cooking when you’re shy of the target temp.
    At the end of the day for any other method, you just need to wait for your meat to get to
    temperature which bring us back to thickness vs time.

    Cheers.

    N.

  • Jean-François

    Einar,

    I finally purchased the THS-113-181 miniature needle probe. I realised the other one was not waterproof! Silly am I.

    JF

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