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  • Infra red temperature measurement of roasting

    Hi all

    Has anyone here had any experience with using infra red thermometers to measure the roasting process? I have looked up Omega, RS & Farnel and they have quite a few reasonably priced meters. One even has a type K output so would work well with the CS meter and software. Key words are bolometer and non contact temperature.

    Searching on CS show no entries about this topic. Home Barista at http://www.home-barista.com/forums/fun-with-roaster-thermometry-t1376.html has "The problem with the IR thermometers is that you can get most any temperature you want depending on where you aim it." I have also found via Google a post on Amazon about a MSC52224A Infrared Thermometer:
    "I use this IR thermometer to roast coffee using a heatgun and a stainless steel bowl. It gives me accurate readings of the temperature of the beans, so I am able to predict what is happening with my roast."

    So has any one used one and very importantly I wonder if it would measure the beans inside the glass envelope of the Gene Cafe. It should if the IR is not attenuated too much.

    Mike

  • #2
    Re: Infra red temperature measurement of roasting

    Mike

    Well they work - sort of.

    The heat haze around the roasting mass tends to cause erratic readings at times.... they see the air and smoke (much hotter than the beans) sometimes.... the actual beans at other times - all a bit hit and miss I found.

    And they definitely wont read the temperature inside glass/plastic but the surface temperature of that glass or plastic - worthless!!

    Compared to a contact type thermocouple in the bean mass - dead accurate and steady readings (which is what you really want).... I relegated my "non contact" thermometer to reading temperature in the freezer.

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    • #3
      Re: Infra red temperature measurement of roasting

      One note Id like to add, while IR thermometers may give you accurate readings to the nth degree, even pro roasters dont take these numbers for face value....it should be used as a guide and a guide only. If you dont aim in the same place for every single roast you do, there is pretty much no use for it.

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      • #4
        Re: Infra red temperature measurement of roasting

        Heres a comment I made on my experience with an IR thermometer. Taken from this post: http://coffeesnobs.com.au/YaBB.pl?num=1121040424/209#209

        Ive found that the InfraRed thermometer works very well for measuring the temp of the empty drum giving a very consistant reading both in the heat up and the cool down stage. Using it to read the temp of the roasting beans though is no where near as reliable. Between the motion of the beans, the hot air being circulated through the drum, the presence of chaff, and the smoke produced by the beans the temp shown by the IR varies too much to rely on it as a precise measurement of the bean temp. With the drum empty the reading is rock solid to the tenth of a degree. With beans in the drum however the reading will vary over about 2C early on in the roast, with the varience hitting over 5C in the latter stages and in some cases (usually with the beans that produce large sized chaff) as much as 10C.
        Fyi It appears Goggle has instituted their 2 year cache retention policy as theyre returning no hits for posts more than 2 years old on here.


        Java "Roasting up a storm" phile
        Toys! I must have new toys!!!

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        • #5
          Re: Infra red temperature measurement of roasting

          Hi all

          Thanks Javaphile for the above link and info.
          There is enough experience there that Ill stick with a thermocouple and saev myself $ testing out an IR.

          Mike

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