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Thread: Hanna Checker

  1. #31
    Join Date
    Jun 2017
    Location
    Sutton, Quebec
    Posts
    21

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    Quote Originally Posted by ldick View Post
    I also had inconsistent results and contacted Hanna. I was told by Hanna that accuracy of their meter is +/- 4% so variations of this amount are to be expected.
    Thanks for this information. I just looked at Hanna's web site and, as you say, they state a +/-4% accuracy. I've had my two sample cuvettes of syrup and the calibration cuvette sitting upright in a closed cupboard since July 10th and just took them out now for a series of measurements being careful to handle them just by the plastic caps not touching the glass etc. Sometimes the measurements are repetitive and sometimes they are +/- 4% i.e. one reading at 48% transmittance the next, seconds later, at 50%. I suppose these results are better than just eyeballing the syrup but I find them disappointingly inaccurate.

  2. #32
    Join Date
    Feb 2010
    Location
    Cape Girardeau, MO
    Posts
    91

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    In spite of the +/-4% accuracy. That is better than my eye sight. And if the syrup is in that borderline area call it the darker grade. Just tell people that darker grades have better flavor,,,,,, really the truth.
    2012 200 taps on buckets,,, Built me a 2' X 11' arch,,, hope to put most on tubing next year.

    2011 100 taps on buckets, 30x 60 flat pan

    2009 63 taps on buckets,,,, 30x60 flat pan

  3. #33
    Join Date
    May 2009
    Location
    UVM Proctor Maple Research Center, Underhill Ctr, VT
    Posts
    3,655

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    Quote Originally Posted by Quebecguy View Post
    I suppose these results are better than just eyeballing the syrup but I find them disappointingly inaccurate.
    The alternative would be a spectrophotometer costing thousands (or tens of thousands) more.
    Dr. Tim Perkins
    UVM Proctor Maple Research Ctr
    http://www.uvm.edu/~pmrc
    Timothy.Perkins@uvm.edu

  4. #34
    Join Date
    Apr 2013
    Location
    Brockport, NY
    Posts
    155

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    The checker, at plus or minus 4 percent accuracy is a decent tool, but not magic in my opinion. I haven't seen or read here about the following aspect so here goes..... If you read the specifications for the checker from Hanna, its accurate to +/- 4 percent at 25 degress C only. Thats 77 degrees F. if I remember right. Any other temperature is not mentioned, either for ambient temp, or sample temp. I think, but don't know, that accuracy would decrease, maybe dramatically, at temps above and below what Hanna mentions as optimal.
    So whats its accuracy at say 40 degrees F ambient and 100 degrees sample? I think Hanna probably has the answers but I can't find any info. Would Matt from Hanna be willing to delve into this?

  5. #35
    Join Date
    Nov 2017
    Location
    Rhode Island
    Posts
    1

    Default Hanna Instruments Response

    Hi,

    Shayla with Hanna Instruments here. I wanted to touch base regarding the questions surrounding the accuracy statements at different temperatures. The only temperature for which we have an accuracy statement for this checker is 25 degrees Celsius, which is a standard reference temperature. It is important to note that temperature will affect the amount of light being transmitted through the sample, as it affects the density of the sample. If the sample is warmer than 25 degree C, it can also cause condensation to form on the cuvette, further affecting the instrument's ability to read the transmittance. We recommend grading the sample when it is in its steady state (not cooling down nor warming up), as the transmittance will change as the temperature changes. So if you tested the syrup while hot, you might expect a change in transmittance when it cools and vice versa. If you are going to be testing at a temperature other than 25 degrees C, we recommend that you test all of your samples at this temperature, to maintain consistency, so that you are comparing apples to apples, and not apples to oranges. When taking any kind of scientific measurement, you should always try your best to minimize the inconsistencies in the process, so the results are comparable. If you do have any questions or concerns, I am always happy to elaborate further. Please feel free to contact me any time at sfranks@hannainst.com or 401-765-7500x 164. I hope this helps!

    --Shayla Franks

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