Beginner’s observations using a PH meter for the first time.

Fellow Brewers, after reading AJ’s posts I found a great deal on Amazon for a Hanna Instruments Bench PH/ORP meter HI4221-01 (if you watch closely you may find that Amazon seems to throw out intermittent deals For a single sale before increasing the price again). I do have some questions after doing a 10 Gallon Porter and I thought anyone new to this like me may have the same questions I do, so here it goes.. If you’re wondering, this is typically an $800 meter, so my hopes are that it is as accurate as the PH buffers that are good to .o1 PH, the meter has accuracy of .002PH +/- 1LSD. I don’t know what 1LSD is?

I Used 17 total Gallons of RO water purchased at a local Grocery Store. The Recipe called for approx 8% darker malts. Using AJ’s approach I added almost 1.75 tsp of Calcium Chloride to the water and I ended up sparging at the end with my well water that typically makes good dark beers. My thoughts were that this end of sparge water really never made it into the Kettle anyway… After Consulting AJ the first time on this brew, His thoughts were that I would be approx 5.4 to 5.5 on my Mash so using the guidelines and not adding any Acidulated would be ok. Being as anal as I am, I wanted to be closer to the middle of his recommendations of being 5.1-5.5 so I used 4 oz Acidulated in the mash…a mistake I think!
AJ wrote; “According to the guidelines you shouldn't need any and I think the guidelines apply here. What I would really encourage you to do is obtain a pH meter and measure the actual pH you obtain in the mash tun. I'm guessing it would be around 5.4 - 5.5 but the only way to know for sure is to measure it.

Cheers, A.J.”
So that’s what I did and here is what I observed.

Observation 1, I checked the PH of the RO water. This made me initially think this PH meter was not going to help me. I poured some RO water into a glass and suspended the probes into it and it was showing a 7.5 PH and went down and down and down…I am thinking what is going on, and walked away to continue with the other steps of the brew… I went back and it had stabilized at 5.96 hence my first question. If it is RO water what should the PH be? I also understand the atmosphere will change the sample but I don’t understand that either. Does the Starting PH of the RO water matter and how should I use it to calculate the amount of Acidulated I would need when compared to the recipe?

Observation 2, I checked the water after treating with Calcium chloride, initially it read 6.05 but stabilized at 6.12. So now I am wondering if going from 5.96 raw RO to 6.12 treated is what I should expect? I also wondered why it went up rather than down as it stabilized like it did with the Raw RO?

Observation 3, I checked the PH at mash in…4.98 and now I was thinking O-man, this is not good I am way too low and I should not have added that Acidulated….but it stabilized out at 5.07, so Now I am wondering, how does the lower of the range effect the beer? I hoped it meant a little lower yield and that is it? My fingers were crossed…

Observation 4, as the mash sat, the PH went up a little bit. ½ hour in it is now 5.13, so I am wondering why it is going up during the mash?

Observation 5, I made the confirmation that the mash is going up because now at the first run off the wort is 5.15. Whew this is going in the right direction and I am in AJ’s recommended range of 5.1-5.5 but on the low side.

Observation 6, at 5 gallons of 13 on the runoff the PH is 5.25 now I am happy. PH at 10 gallons of runoff was 5.3, but why is it going up?

Observation 7, As I focused on Plato (what I typically use for an indication of over sparge), I found the PH stable at around 5.3 and it edged up to 5.32 at Plato 5. I stopped sparging at Plato 4. But I didn’t check the PH because I was focusing on boiling wort. Now I am wondering if PH could be used to determine when to stop sparging or if Plato a better method?

So that is it and now hopefully one of you can add insight to these observations?

Lastly, thanks for all the help from this forum…You guys and gals Rock!

2funkids said:

Fellow Brewers, after reading AJ’s posts I found a great deal on Amazon for a Hanna Instruments Bench PH/ORP meter HI4221-01 (if you watch closely you may find that Amazon seems to throw out intermittent deals For a single sale before increasing the price again).

Click to expand...

Good score!

2funkids said:

I do have some questions after doing a 10 Gallon Porter and I thought anyone new to this like me may have the same questions I do, so here it goes.. If you’re wondering, this is typically an $800 meter, so my hopes are that it is as accurate as the PH buffers that are good to .o1 PH, the meter has accuracy of .002PH +/- 1LSD. I don’t know what 1LSD is?

Click to expand...

With pH buffers accurate to 0.01 pH, a temperature probe accurate to about 0.5 °C and voltage measurement accuracy better than 0.5 mV (all of which your instrument exceeds so it is the buffers that set the accuracy) you should get slightly better than 0.01 pH accuracy in the region about half way between the pH of the two buffers (4 and 7). 1 LSD means 1 Least Significant Digit i.e. if the reading is 4.123 pH then the error is ±0.00223 pH (= sqrt(0.002^2 + 0.001^2) from the meter. The buffers will be the determining factor.

2funkids said:

Being as anal as I am, I wanted to be closer to the middle of his recommendations of being 5.1-5.5 so I used 4 oz Acidulated in the mash…a mistake I think!

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Not a terribly serious one though. My approach would be to have the sauermalz ground and ready to go. After checking mash pH without and finding that it is higher than you would like is the time to add the sauer malz. Incrementally. Next time you brew the beer you will know about how much sauermalz is required in advance and can add it to the grist.

2funkids said:

Observation 1, I checked the PH of the RO water. This made me initially think this PH meter was not going to help me. I poured some RO water into a glass and suspended the probes into it and it was showing a 7.5 PH and went down and down and down…I am thinking what is going on, and walked away to continue with the other steps of the brew… I went back and it had stabilized at 5.96 hence my first question. If it is RO water what should the PH be? I also understand the atmosphere will change the sample but I don’t understand that either.

Click to expand...

RO water is low in mineral content (close to DI water) so it has very low alkalinity (buffering capacity). Because of this carbon dioxide from the air which dissolves in it causes the pH to be appreciably lower than that of pure DI water. Add to this the fact that RO/DI water has low conductivity. This means that pH electrodes take a long time to stabilize and you can see that drift is to be expected. If low "ionic strength" solutions like RO water are to be measured special buffers and chambers which protect the sample from the air are used. 5.96 is pretty low for the pH of DI water. It implies carbon dioxide levels in the air 30 times what they actually are. It is not uncommon to see pH that low from soft well water but in a well the partial pressure of CO2 is easily 30 times what it is in the air at the surface. For RO water it depends on what was in the RO water originally and how much of what got removed in the RO process.

2funkids said:

Does the Starting PH of the RO water matter and how should I use it to calculate the amount of Acidulated I would need when compared to the recipe?

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No, it doesn't matter because whatever it (the pH) is, the buffering capacity is so low (there is so little dissolved in the water) that whatever is added by malt totally overwhelms.

2funkids said:

Observation 2, I checked the water after treating with Calcium chloride, initially it read 6.05 but stabilized at 6.12. So now I am wondering if going from 5.96 raw RO to 6.12 treated is what I should expect? I also wondered why it went up rather than down as it stabilized like it did with the Raw RO?

Click to expand...

There could be a couple of things going on here. Adding a neutral salt (calcium chloride) to water would have only a very small effect on the pH (because it increases the ionic strength of the solution). But it will have a profound effect on the conductivity. Thus the reading after addition of calcium chloride is doubtless more stable and probably accurate that the reading on the untreated RO water.

I will say that mystifying pH readings are not unusual for people just starting out using pH meters. Be sure to calibrate often and to follow instructions that came with the meter scrupulously. Be sure to rinse the electrode with DI water when moving it from buffer to buffer or buffer to sample or sample to sample. Be sure to calibrate daily. If you get a reading that looks strange for any reason, rinse the elelctrode with DI water, blot it dry (don't actually touch the glass bulb) and check pH of the buffers. Use fresh buffers when you calibrate.

2funkids said:

Observation 3, I checked the PH at mash in…4.98 and now I was thinking O-man, this is not good I am way too low and I should not have added that Acidulated….but it stabilized out at 5.07, so Now I am wondering, how does the lower of the range effect the beer? I hoped it meant a little lower yield and that is it? My fingers were crossed…

Click to expand...

It's pretty much the same as when the pH is too high. Away from the optimum range you get suboptimum enzyme performance. But 5 isn't that far from the optimum range and see next comment. I think you'll probably be OK.

2funkids said:

Observation 4, as the mash sat, the PH went up a little bit. ½ hour in it is now 5.13, so I am wondering why it is going up during the mash?

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I have noticed with sauermalz that mash pH rises with time. What you are seeing here is entirely consistent with what I have observed.

2funkids said:

Observation 5, I made the confirmation that the mash is going up because now at the first run off the wort is 5.15. Whew this is going in the right direction and I am in AJ’s recommended range of 5.1-5.5 but on the low side.

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So I think all should be well but next time skip the sauermalz in this beer. I think the reason for the increase over time is that it takes a while for the lactic acid in the sauermalz to be extracted into solution and to react with the malt's buffering systems.

2funkids said:

Observation 6, at 5 gallons of 13 on the runoff the PH is 5.25 now I am happy. PH at 10 gallons of runoff was 5.3, but why is it going up?

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I am assuming that sparging is underway here and that the rise is because the acid in the mash is being diluted by the sparge water.

2funkids said:

Observation 7, As I focused on Plato (what I typically use for an indication of over sparge), I found the PH stable at around 5.3 and it edged up to 5.32 at Plato 5. I stopped sparging at Plato 4. But I didn’t check the PH because I was focusing on boiling wort. Now I am wondering if PH could be used to determine when to stop sparging or if Plato a better method?

Click to expand...

I usually recommend checking pH and gravity. If pH is OK at the gravity at which you usually stop as demonstrated over a couple of different brews of different styles then you can forget about checking pH in the future and just use gravity.

A.J. Thanks for the guidance on this, this is VERY helpful. Now I am curious why the PH reading on the RO was what it was. Back when I stopped at a local water conditioning business that does RO systems they showed me a cartridged that was used to re-introduce minerals into RO water. Thay said without it the pipes would be broken down by the water. Does anyone know if the typical RO water systems at the Grocery store has this type of conditioning that puts minerals back into the water?

Remember that an RO system does not remove everything. In my system, for example, the water going in has (conductivity based) TDS of about 60. The permeate reads 3-5. Presumably if the feed TDS were 600 the permeate would be 30-50 i.e. almost as much as my feed water.

All the plumbing downstream of the RO cartridges is non metallic thus no problems with the corrosive nature of soft water. I wouldn't think that an in-store vending setup would re-introduce minerals as the consumer usually fills jugs at the machine i.e. no plumbing to corrode.