Is it the meter, or wrong calibration?

[ggriffi]

I have started use a pH meter when brewing, and I had an issue brewing yesterday. Some background, I use a Hanna 98128 meter that is stored properly and have no problem calibrating. I also have Bru n' Water to use and a report from Wards.

When I started yesterday and had the meter calibrated ( 4&7 buffer ) I had the bright? idea that I wanted to check the pH of my water BEFORE I added the lactic acid that was needed. So I get a sample of water to test and the meter doesn't stabilize as I watch the display go a full point higher then my pH of 7.8. Took the meter out, cleaned it, tried again and same result as before. So I add the lactic acid and pray because now I'm NOT sure what the pH really is, even though I have the water report. So I'm thinking there is something wrong with the meter, and that maybe my probe is bad. After some searching, I read that when I am calibrating the meter with 4 & 7 buffers it is basically bracketing the meter's calibration for the solution intended to be tested.

So my questions: If I read that correctly does that mean if I want to check the pH before additions I would need use 7 & 10 buffers? And then re-calibrate with 4 & 7 to check mash pH? Do any of you check your water before or do you just take the number from the water report and roll with that? Or is just possible that my probe is bad and I need a new one?

 

[Silver_Is_Money]

It is sometimes hard to read the pH of water alone, as it generally doesn't have many ions in it whereby to solidly buffer it at a specific pH, and the lack of ions also means there isn't much current flow for your pH meter to lock in on.

What is the source for your water? Is it single or multiple sourced? Does our local water authority change it seasonally?

Aside perhaps for sparging, wherein there is a need to reduce alkalinity, it isn't water pH that is generally of concern. It is mash and post boil pH that are of concern.

 

[ggriffi]

It is sometimes hard to read the pH of water alone, as it generally doesn't have many ions in it whereby to solidly buffer it at a specific pH, and the lack of ions also means there isn't much current flow for your pH meter to lock in on.

What is the source for your water? Is it single or multiple sourced? Does our local water authority change it seasonally?

Aside perhaps for sparging, wherein there is a need to reduce alkalinity, it isn't water pH that is generally of concern. It is mash and post boil pH that are of concern.

I use my tap water water as the only source for brewing and I'm not sure if the WC adjusts their water seasonally or not.

I biab so no sparging for me. I just wanted to test my meter against tap water to see how well the meter did. When the meter went nuts, I panicked a bit thinking somehow the meter was going bad, even though I calibrated the day before. So I just went with my addition like normal and hit my numbers. I didn't check mash or post boil pH since I thought the meter was inaccurate at best.

 

[Silver_Is_Money]

Did you store the probe in a 30-35% concentrated KCl solution overnight after calibrating it for next day use? Hanna is a highly reputable company.

 

[ggriffi]

Yes I have a bottle Hanna's storage solution and use it. I really think that as you first said
It is sometimes hard to read the pH of water alone, as it generally doesn't have many ions in it whereby to solidly buffer it at a specific pH, and the lack of ions also means there isn't much current flow for your pH meter to lock in on.

 

[ScrewyBrewer]

I bought my Hanna HI98121 about 5 years ago and it shipped with 4.01 and 7.01 calibration solutions. I was surprised to see that the HI73127 replacement electrodes cost $125 each now since I am on my third electrode. Fortunately, after correctly using and maintaining my meter, it's been over two years since needing a replacement electrode.

The first time I checked the pH of some RO water and getting a reading well below 4.00 pH I was surprised too. Back then I thought it would measure closer to 7.00 pH. It seems the carbonic acid formed in the water when coming in contact with room air easily dropped the pH.

Before calibrating and after each use, I soak the electrode in the Hanna HI7061L cleaning solution and store it in the Hanna HI70300L storage solution. It pays to clean, calibrate, and store the electrode away using fresh solutions every month or two especially if you haven't used it. Allowing the electrode to dry out is a guaranteed reason to order a replacement electrode.

 

[ggriffi]

On Hanna's site the electodes are $59 I plan on ordering one in the next week or so. The thing that got me was it going up and up on my water and I panicked a bit , and then went on with my additions since I have a good water report (Wards). Mine is about the same age as yours and if I am just now needing one I'll thank my lucky stars and move right along

 

[Vale71]

The PH of water is irrelevant so why bother measuring it?

In any case you are correct, if you want to measure a PH>7 you'd need to calibrate with 7 and 10 calibration solutions and then calibrate again with 4 and 7 to measure mash PH.

 

[VikeMan]

The first time I checked the pH of some RO water and getting a reading well below 4.00 pH I was surprised too. Back then I thought it would measure closer to 7.00 pH. It seems the carbonic acid formed in the water when coming in contact with room air easily dropped the pH.

CO2 does reduce the pH of pure water. But it shouldn't get to 4.0 or even close to it. I suspect what you experienced was the lack of TDS (and thus low conductivity) causing a sort of random pH reading.

 

[Silver_Is_Money]

CO2 does reduce the pH of pure water. But it shouldn't get to 4.0 or even close to it. I suspect what you experienced was the lack of TDS (and thus low conductivity) causing a sort of random pH reading.

RO and distilled water settle in at about pH 5.6 over time due to CO2 absorption, whereby water plus carbon dioxide form carbonic acid. But it is so few ions as to be irrelevant. The reaction is highly reversible and reaches equilibrium at ~pH 5.6.

H2O + CO2 <--> H2CO3

 

[ScrewyBrewer]

On Hanna's site the electodes are $59 I plan on ordering one in the next week or so. The thing that got me was it going up and up on my water and I panicked a bit , and then went on with my additions since I have a good water report (Wards). Mine is about the same age as yours and if I am just now needing one I'll thank my lucky stars and move right along

Whew! Thankfully you are correct, I am not sure how I managed to hit Hanna's Australian site where I saw the $124.30, that price was admittedly shocking, to say the least.

 

[ggriffi]

I looked at Amazon and I believe they are right at $100

 

[ScrewyBrewer]

I looked at Amazon and I believe they are right at $100

I recommend buying replacement parts and solutions directly from Hanna'a US site for the best prices and quality.

 

[ggriffi]

I recommend buying replacement parts and solutions directly from Hanna'a US site for the best prices and quality.

100% this

 

[mabrungard]

You guys are lamenting the cost of replacement electrodes on those 'all in one' meters. That's why I continue to STRONGLY recommend that brewers use an industry-standard, BNC-cabled probe and meter. A very robust, reliable, and durable replacement probe can be had for around $40. The meter itself will last almost forever.

And speaking of meters, I'm not a big fan of computerized or digital meters since they seem to go haywire more easily. My Milwaukee MW-101 is now over a decade old and going strong. Yes, this 'manual' meter is slightly more work to calibrate. But its not that bad and they generally stay in calibration as long as the probe isn't abused.

 

[ggriffi]

You guys are lamenting the cost of replacement electrodes on those 'all in one' meters. That's why I continue to STRONGLY recommend that brewers use an industry-standard, BNC-cabled probe and meter. A very robust, reliable, and durable replacement probe can be had for around $40. The meter itself will last almost forever.

And speaking of meters, I'm not a big fan of computerized or digital meters since they seem to go haywire more easily. My Milwaukee MW-101 is now over a decade old and going strong. Yes, this 'manual' meter is slightly more work to calibrate. But its not that bad and they generally stay in calibration as long as the probe isn't abused.

I'll have to take a look at it as it's only $20 more than the probe I need.