Advice needed from the Ph-Meter savvy brewers out there

Discussion in 'Homebrewing' started by Finn, Jan 11, 2016.

  1. Finn

    Finn Initiate (0) Nov 20, 2003 Pennsylvania

    Hey folks, I just bought a ph meter (Dr. Meter ph-100 model) off amazon and in looking through the manual I see that it has 3 point calibration instructions: 4.0, 6.86, and 9.18 ....Can I still just do my two point calibration with the solutions I bought with it (7.0, 4.01) or are these meters only designed to calibrate within these specific confines stated in the manual? I can't even find calibration solutions in bulk (with a short search anyway) that are 6.86 or 9.18. It just came with a couple little packets of each.

    Thanks for any info/thoughts
  2. hopfenunmaltz

    hopfenunmaltz Meyvn (1,363) Jun 8, 2005 Michigan

    I would think the 7.0 and 4 would be fine, as we are dealing with data in that range.

    7.0 balances the circuit, 4 sets the gain. I go back to 7 to see and correct for interactions, then check the 4 again. If I check at 10 it shows how linear it is over a wide range, but that is often a little off.
    GUNSLINGER likes this.
  3. DunkelFester

    DunkelFester Initiate (0) Aug 24, 2004 Pennsylvania

    +1. Always wise to go back and check the measured values of your calibration buffers!

    To the OP: 6.86 and 9.18? I've never seen a pH standard solution with such seemingly random values. You can find buffers from pH 1.00 through 14.00 (usually +/- 0.02 at RT) in 500 mL bottles from a number of sources online for anywhere from ~ $15 to $70 (if you need a CoA - which you don't).

    Anyway, as long as your meter lets you choose the number of buffers AND lets you enter the pH value for each calibration point? A 2 point curve from 4 - 7 is perfectly fine (assuming you're using it to check the pH of your mash). If you're going to use it to check and adjust your strike water pH? You might want to use the third point. My well water pH is a lot higher than 7.
  4. Finn

    Finn Initiate (0) Nov 20, 2003 Pennsylvania

    Cool, thanks for the input guys, I'll check to see if I can enter the calibration values for the solutions or not.