I am new to pH measurement. I test my 1st 2 batches without filtering out the grains so I have learned that will potentially cause a low reading. I have a new milwaukee 101 meter. This weekend I brewed and tested the mash 10 min in and was at 5.5 (bru’nwater estimated 5.4). I rinsed the meter in RO water and tested distilled water and got 7.5 (I assumed this should be 7).
I am calibrating with the packets that came with the meter which I assume to be diluted giving me erroneous readings. I will get new solutions but any other newbie pH meter user suggestions?
Ive found freshly opened distilled water tested right away has PH in the 6 range. As it sits out it will dissolve CO2 from the air and the resulting carbonic acid formed can drop the PH lower.
calibration will be the key to most accurate readings. If performed correctly with 2 point calibration (4 and 7 PH solution for brewing purposes) you should be able to get a fairly accurate reading. Your meter resolution capacity and ± accuracy specs define how accurate a reading you can achieve.
Yeah, I wouldn’t worry much about testing the pH of distilled water. Since it lacks buffering, it can vary quickly due to things mentioned like dissolved CO2.
As long as your calibration solution measures correctly, you’re ok. Also, you should be measuring at room temperature.
Measuring at room temps include not only the calibration solutions but also your mash sample. I have had best results getting the mash sample temp as close as possible to the temps of the calibration solution as well. BTW, I am pretty sure that those packages of calibration solution that come with the meter in the box are a one time shot. Once you open them, they are not meant for repeated uses.
I test my 1st 2 batches without filtering out the grains so I have learned that will potentially cause a low reading.
I don’t believe that filtering or not filtering out the grain particles will affect the pH reading. I could be wrong, wouldn’t be the first or, likely, the last time.
Always clean the probe with distilled or RO water between transfers so that calibration solution, storage solution and/or wort solution are not contaminating each other. It’s best to have a squirt bottle of distilled water handy for these transitions.
Always try to take measurements of wort at room temperature. The ion selective glass membrane (the business end of the pH meter) is a delicate thing. If you’re working with a non-analytical grade pH meter, it’s even more important to take good care as the glass membrane, seals, connections, etc are typically not as robust.
Get a good storage solution and always keep your probe submerged in it when not in use. pH 4 solution with excess KCl dissolved in it makes a good storage solution.
pH measurments being logarithmic, it’s best practice to recalibrate before each brewing session even if you brew as often as once per week. pH = 5 vs pH = 6 is a tenfold difference in acid concentration.
I have found this to not be as effective as using a fully grain/husk free sample. When I took my very first sample for measuring my pH, I did not strain out the grain/husk material and it read very low (like 5.1). I thought that was a bit off as I was shooting for a 5.4, so I took another sample and ran it through a fine mesh bag prior to measuring pH. This one came out around 5.35, so I can only attribute that difference to the grains in the sample taken. I make it a point to only take measurements on samples that have been strained now for more accurate results.
I’ve never filtered my pH sample and my results usually match, within the major of error for my meter, the Brunwater prediction.
I’ll take a larger sample next time and filter part of it, now I’m curious to see the difference in the pH of the two samples.
So, how much do I need to dry off the probe after calibration or testing? I have been blotting of the outside with a paper towel. I like the idea of the spritzer bottle filled with distilled water.
I may have miss spoke. I don’t dry off the tip, or the glass part. I have blotted off the plastic above that. Seemed to me the rinsing water droplets left on it might affect my reading. I am probably over complicating it.
I quickly spray down the probe and wand after every sample/calibration solution reading I take with distilled water. Then I dry off the wand with my shirt and blow off the water on the probe with a couple quick breath blasts prior to taking my next reading.
Ok, recalibrated with fresh solutions and brewed a table saison. Estimated mash pH was 5.2. Measured was 5.06, first running was 5.23 and post boil was 5.20. The beer was supposed to be about 5 SRM but looks darker so my some of my grains my have had higher Lovibond ratings than expected. I put in the low end of the ranges (used 1 lb of Munich malt which has a 9 to 19 L range ) this may account for some of the error. My other thought was my collection method. I doughed in, let it rest 10 min then skimmed my sample from the top of the MT. Should I have stirred first? Also what should I expect in pH changes from the start of the mash to the end and then after the boil?
FWIW I let it ride without adjustments and hit my target OG on the head. Before I knew what I was doing, I was adding twice as much lactic acid than I did here to mashes and the beer came out good. My efficiency has seen a huge jump since attempting to hit a proper pH. I was 76 percent on this beer.
Yeah dont touch the probe. Tap water in a glass is ok for brewday storage, then when youre done, rinse it with storage solution or distilled water, then store in recommended storage solution. Tap or distilled water or storage solution in a glass will keep the probe wet and neutral while you mash, allowing you to simply remove the probe, shake, and insert into your test liquid. Swirl in the glass to get the probe readeing a homogeneous solution, that should work fine. The probe should not be touched or dried at any time. The test liquid should be cooled from mash temps to room temp. I learned that this will extend the life of the probe as well as make one’s readings more accurate.
Yeah proper ph does wonders for efficiency. Dont sweat a .1 ph discrepancy. At the end of the day thats a rounding error in the scheme of things.