I know we have a few of these threads going so please bear with me or avert your eyes.
I have been mildly questioning my meter lately and also going over multiple Ward Labs reports I have gotten. Years ago I got a Ward report that showed my water’s pH (filtered Lake Michigan tap water) at 6.6. I also remember being at a commercial brewery where the brewer told me that the water pH was 6.6 and I was also helping a friend in another commercial brewery (long story) and he asked about the pH of the water and I told him it was 6.6. There was [what looked like] a very high-end pH meter there and he measured the pH and it was 6.6. My latest report from Ward Labs (August 2020) shows the pH at 7.9. I have taken the pH of my source water a few times since then including today and I am always right around 6.7 each time. I have to assume that Ward’s pH equipment is excellent, right? So is my meter wrong? Was the sample that I sent to them somehow compromised? I filtered some water into an empty, dry water bottle (like AquaFina, etc). Could the pH of the sample have changed somehow? If someone were to take a sample of the water would it be necessary to let the water run for a bit assuming that the pH of the water still in your plumbing could be different than the ground water? I’m just trying to figure out if my meter is telling me the truth or if there is some user error here or what. Thanks Beerheads.
EDIT: I also just got some new calibration solution (4.0 and 7.0) and the 4.0 label actually said that at cooler temps (70°) it would read 4.02 and at higher temps (80°) it would read 4.00. My meter read it in the cooler basement temps at 4.02. That seems pretty solid.
Agreed! Waters pH is quite highly irrelevant. Waters Calcium, Magnesium, and Alkalinity (as CaCO3) are what matters.
For example: My almost neutral pH well water (which tests at between 7.2 and 7.7 pH via a handful of sources) has a whopping 377 ppm of Alkalinity per Ward Labs.
I’m not chasing my water’s pH. I’m trying to determine if my meter is properly reporting ANY pH properly. If my meter can’t tell me the pH of my water then it can’t tell me the pH of my mash. What I want to do is get my strike water to a pH of 5.5 and I can’t know if its 5.5 if my meter seems dodgy.
Thank you. I have done that and I have used my pH of 6.6 to try that test and the BNW results were very close. I did not try it on the 7.9 pH report that I got and I should try that. I am just trying to understand how Ward could show a pH of 7.9 when that does not align with anything that I have ever seen with my water. But I find it hard to argue with assuming their equipment is top-notch and well-maintained. So could my sample just have been bad somehow?
When I calibrate my pH meter (Milwaukee SM-102). I get 7.01 and 4.01.
How old is the probe in the meter? My guess is if it calibrates properly, the probe is OK. If it takes a while to read one of the buffer solutions or stops calibrating, it’s a time for a replacement probe.
FYI to the group, I always check my sparge water and add acid to get between 5.2 and 5.6. I need to know where it starts so I don’t overshoot. Granted the untreated water sometimes takes a while to get a stable reading, but I usually get there.
Omega PH7011 meter here with a new probe in the last 12 months. Sometimes it does take awhile to get a stable reading and sometimes I take a sample of tap water and get a reading (say 5.78) and then go grab another sample but let the water run longer so I am getting true ground water and then I’ll get a reading of 6.71. This suggests that I really need a lesson in the proper way to get a sample and how to take a reading. I know things “stratify” and I know that the pH is variable throughout the process so I’ll assume there is some user error. I’m not trying to beat this topic to death and get overly detailed about it but I feel like I need to trust my instruments and then when I see a pH of 7.9 from Ward… I start to question everything.
If your meter is reading fresh calibration solutions correctly, I’d be inclined to trust your meter over the Wards value. Who knows what could have happened; 6.6 vs. 7.9 is a big disparity.
If a difference of 1.3 pH units was translating to your mash pH, it would be way out of whack and your beers would probably be suffering for it. How have they been turning out? That’s sort of the ultimate test of a pH meter.
I have been having some issues lately, mainly with clarity, haze, etc. and I am trying to simplify some things. I agree that discrepancy is big so then it makes me wonder about a water bottle with 4 ounces of tap water in it, going through the mail or UPS or whatever and what impact could there be on the water and its pH as it travels and gets to the lab. Or… would the sample not be impacted by that? I agree though that if my meter is reading brand new calibration solutions correctly then I have to trust it. Which means that I have to throw out the Wards number which seems unbelievable to me.
Degassing of water (removal of co2 in this case) will drive carbonic acid out, thus raising ph. If putting in a large container, and not much volume, will promote a larger headspace thus more disassociation/equilibrium.
When degassing water with N2 its not uncommon to see a very large spike in pH, due to replacing the co2(acidic) with N2, much less acidic.
If the probe calibrates (short of buying a few more probes and calibrating), thats all you got.
So it could be possible for Ward to measure the pH and have it show high because of the way I packaged it? I would conclude that my choice of container and the way I packaged it could cause an issue. It’s also possible that on earlier samples I used a smaller bottle and filled it all the way to the top. Pretty sure Ward measured my water at a pH of 6.6 numerous times prior to this last one in August 2020.
Okay, no need for anyone to get prickly, kids. I could potentially solve this by asking Ward about the best possible way to package the sample and send them another one sometime in the near future. Also, my neighbor’s wife is heavy into gardening and I wonder if she has a pH meter. If so, I could borrow it and test a sample of my tap water with my meter and hers and see what happens. I have multiple Thermapens in case I start to distrust one of them but I only have one pH meter. I also have some old test strips but I’m not sure I would trust them to cross-check my meter.
What about the sample-taking part? What if I wanted to measure the pH of my tap water so I go to my kitchen sink and just open the tap and get a small sample and measure it. Then I did it again but I let the water run for a minute so I’m not getting water that is sitting in the pipes. Could the measurement be different? Yes, no, maybe but not enough to matter?
What is the latest information for how long into the mash to wait to take an accurate pH measurement? I have heard a number of brewers say they wait until about 20 minutes into the mash. But once I set my mash cap and close up the mash, I really don’t want to muck around in there to get a sample? How and when are most of you measuring mash pH?
For grins and giggles I did my own pH tests on regular and degassed water samples. A 100 mL water sample straight from the tap was pH 6.96. I then shook the sample very vigorously for 30 seconds (it was in a 250 mL mason jar). pH was 6.92. I then took a reading in the Brita filter, just to be thorough. It was 6.98. All very similar.
Interestingly, my Wards water report shows a pH of 7.8, which is consistent with my city water report. So I have a similar, albeit smaller, disparity.
In summary, I have no idea what’s going on, but I will continue trusting my pH meter until weirder stuff happens.
Thank you for that. I appreciate it. That is very strange. I wonder how many other brewers see a difference between what their meter says and their Ward report. I do agree… my meter is reading brand new calibration solution properly so I have to trust it. I also reached out to a brewing bud who lives about 15 minutes from me and asked if I could borrow his meter. It would be great to see two meters agree on the same sample or at least be close.