I own a Extech Ph220 and I just picked up a Extech PH110. I calibrated both using Ph 4, 7 and 10 at the same time. Then tested each on the 4.0 solution, reading were only off by +/- .05 per meter. I tested the raw milk and Extech Ph220 reading was 6.8 and the Extech PH110 reading was 6.6. Okay not a big deal, however testing after 45 minutes after started the reading went nuts. The Extech Ph220 read 6.5 and the Extech PH110 reading was 6.2. Then after rennet and cutting the Extech Ph220 read 6.3 and the Extech PH110 reading was 5.9. Then at the start of cheddaring the Extech Ph220 read 6.0 and the Extech PH110 reading was 5.5. So which meter is being true, it is strange as I put it back in the calibration solution the read within 0.5 of each other. Anyone have any insight?
In the morning I will be making a Jarlsberg and would like to be able to run an accurate PH level. As usual all help is welcome
You should be calibrating with 7 first and then 4. That's what Extech recommends.
I have an Exstik pH100. It started to drift up and down and all around. I soaked the tip in Rinsing Solution and that cleared my drift problem.
-Boofer-
Boofer,
I did follower the manufacture recommendations on calibrations, I soaked the tip in solution provided within packaging for 24 hours(Recommended was ten minutes), same result, then I soaked the sponge (in tip cap) with solution #4, put the cap back on (24 hours later) with the same result and then I calibrated with 7 then 4 then 10. Then I proceeded with the results as I posted above. Go figure meter's still do not agree
I would talk to Extech
drift too significant, with new meter most likely probe issue. See what they say about getting you a new one.
To my understanding you always start calibrating with the most basic solution to the most acidic. so 10 7 4
Yes, exactly, but one only needs to calibrate between the two standards that encompass the anticipated sample. So say one expects a basic measurement of 8.5, then 10 and 7 would be appropriate. Whereas with cheese, it's not necessary to use the 10 buffer. It's not wrong to do it, just overkill. It doesn't do much for accuracy. If there's significant drift like that and the probe is not clogged (both bulb and junction), then there's an issue with the age of the probe. They do have a limit, though some last longer than others.
I received the new PH probe today, I have replaced what I think to be the bad one. I will be making a Gouda in the morning, so we will see how close the two meters are now.
I like to get little sample in the measuring cup and put that in tall glass.
And then I put PH110 in that sample, and it takes 2 mins to stabilization... maybe :)
Good luck..
Hande
Edit.
I have been pleased with that PH110 meter, until I have learned it's trick. ;D
Well the new probe seems to have taken care of the drift problem, readings between the two meters differed by .02 at any given test. The Gouda make went well and they are both in the press.