A couple of months ago, I bought a Milwaukee MW101 pH meter.
One thing I wasn’t expecting is that it takes about 2-3 minutes to get an accurate reading. When I first insert the probe, the initial reading is usually around 7 or 8, and then it slowly starts going down until it eventually settles at the final reading. I have found that gently stirring the probe in the sample speeds the process up a bit and actually seems necessary to get an accurate reading (as confirmed with testing solutions).
I’ve never heard anyone mention this before. Is it normal or do I have a bad probe (it’s only about 6 months old, and I store it in the recommended storage solution)?
to be fair, it could be 45secs or 3 min - I usually am doing other stuff, keeping the corner of my eye on the readout until it looks like it has stopped before I pay attention.
I also found that swirling the probe in the wort solution helps speed things up.
I have the same meter and I find that the reading settles out in about a minute or less. I am not concerned with a few tenths of additional settling as long as I can get a fairly stable reading (no more than a tenth or two drift over 20 seconds).
One thing that I want to point out is that I take all of my readings 10min into the mash, and I also chill my wort sample down to R.T. prior to taking a reading. I also calibrate my meter at 4.01 and 7.00 prior to taking a reading.