Measuring Kettle PH

[refect]

I've been focusing on kettle PH and post fermentation PH lately. Mainly with my massively hopped IPAs.

So my question to those who like to keep track of kettle PH is...How are you all measuring your pre/post boil kettle PH? Should this be done at hot/warmer temps, or are you cooling it to room temp before taking your readings? I've been searching to find clarification on this, but cannot seem to find a solid answer on recommend temperature when checking kettle PH.

I know the recommend range for mash PH is generally measured at room temp, but say I wanted to lower my kettle PH towards the end to 4.9/5.0 in order to prepare for a large whirlpool hop addition. Should I be measuring this at my anticipated whirlpool temp, or cool it to room temp and measure like I would during the mash? I know PH readings change depending on temperature, so this is why I ask. I want to make sure I am dialing in where I want to be correctly.

Same can be asked for pre boil ph? Are you just dunking your probes in the wort shortly after sparging is complete and heating up to a boil, or do you pull a sample and cool it to room temp and measure?

 

[day_trippr]

I always record pH at multiple stages during a brew, including pre-boil and post-boil pH, along with mash pH at 20/40/60 and end-of-runnings (I fly sparge). But regardless of when I take the sample, I always cool it to 70°F before taking both pH and gravity readings...

Cheers!

 

[refect]

I always record pH at multiple stages during a brew, including pre-boil and post-boil pH, along with mash pH at 20/40/60 and end-of-runnings (I fly sparge). But regardless of when I take the sample, I always cool it to 70°F before taking both pH and gravity readings...

Cheers!

Thank you! I will stick with room temp measurements throughout my readings and see how it works out!

 

[Bramling Cross]

Temperature and pH...*shudder.* Yeah, it can sometimes be a bit confusing if you find yourself consulting older resources.

Fortunately, writing in 2024, I think it is reasonably safe to assume that we're all on the same page and anything written in the past twenty-five years assumes that pH measurements are taken at room temperature.

Also, congrats on tracking your kettle pH. It makes a difference.

 

[refect]

Temperature and pH...*shudder.* Yeah, it can sometimes be a bit confusing if you find yourself consulting older resources.

Fortunately, writing in 2024, I think it is reasonably safe to assume that we're all on the same page and anything written in the past twenty-five years assumes that pH measurements are taken at room temperature.

Also, congrats on tracking your kettle pH. It makes a difference.

Thank you! Over the years I've always tracked my mash PH, but never bothered messing with kettle PH, or even messing with PH post fermentation. The majority of my beers have always come out tasting delicious. Some super crushable, but I know they could be better. My flavors and aromas have always been pretty well on point for what I am hoping to achieve, but I tend to find the beer may not always be as crisp as I want, or there is some slight astringentcy to it/bitterness may not be as smooth as I want.

I am hoping that as I track my PH more in depth, that I can fine tune some of my already solid recipes and better my process in general for future recipes.

 

[Indian_villager]

So I'm using a pH meter with temperature compensation, so I just cool the sample within the temperature range recommended by the meter manufacturer and take my measurement.

 

[dmtaylor]

So I'm using a pH meter with temperature compensation, so I just cool the sample within the temperature range recommended by the meter manufacturer and take my measurement.

Yeah...... that... doesn't work.

 

[DuncB]

Also the hotter wort will deteriorate the electrode quicker.
I put a mug in the freezer and then put the hot sample into this and it soon drops to about 20 degrees.

 

[Indian_villager]

Yeah...... that... doesn't work.

You have evidence or just ellipses? I am a chemical engineer by trade. I've had plenty of ATC pH probes in all sorts of industrial applications from biopharmaceutical to continuous commodity chemical processing ATC works you just have to make sure the temperature reading is accurate too. If anything cooling and agitating samples without a nitrogen blanket will shift the conductivity/pH due to absorption of atmospheric CO2 (see USP 645 or guidance put out my Mettler Toledo Thronton). The extent to which the pH reading is impacted by cooling and agitating in open air will vary massively depending on the buffer capacity of the sample, but it will shift.

EDIT: This bs is wrong. I confused conductivity temperature compensation with pH. See post #25 below for correction.

 

[Indian_villager]

Also the hotter wort will deteriorate the electrode quicker.
I put a mug in the freezer and then put the hot sample into this and it soon drops to about 20 degrees.

Sorry for double reply. Yes you are correct, the elevated temperature will degrade the probe sooner, however it does not degrade the probe fast enough to justify the extra work around properly cooling the sample when replacement probes are available fairly inexpensively, ~$40/2yrs. And as for freezing the beaker, I would caution against that because you increase the potential to contaminate your sample with frost buildup on the beaker leading to an offset in your reading. Additionally I know I'm being pedantic with lab practice but I fill my beaker and dump out the beaker twice and measure on the third collected sample. I toss the dumped material into a mason jar and only return it to whatever vessel I'm measuring after I have collected my sample to be measured.

Additionally you can use the cleaning solution every few brew days to make sure you don't have a buildup of organic material on the bulb which slows down readings.

 

[dmtaylor]

You have evidence or just ellipses? I am a chemical engineer by trade. I've had plenty of ATC pH probes in all sorts of industrial applications from biopharmaceutical to continuous commodity chemical processing ATC works you just have to make sure the temperature reading is accurate too. If anything cooling and agitating samples without a nitrogen blanket will shift the conductivity/pH due to absorption of atmospheric CO2 (see USP 645 or guidance put out my Mettler Toledo Thronton). The extent to which the pH reading is impacted by cooling and agitating in open air will vary massively depending on the buffer capacity of the sample, but it will shift.

Ah, so you have the fancy thousand-dollar gadgets. That's different. Carry on.

 

[mac_1103]

Ah, so you have the fancy thousand-dollar gadgets. That's different. Carry on.

I think it's still important for anyone who stumbles onto this thread five years from now to know that it doesn't work with a $30 meter from Amazon that claims to have temperature compensation. The average homebrewer with average homebrewer resources is going to have to chill the sample to the temperature that the meter is calibrated at. As I've mentioned a few times before, I really should have stolen a lot more stuff from all the labs I worked in over the years.

 

[Indian_villager]

Ah, so you have the fancy thousand-dollar gadgets. That's different. Carry on.

I have a MW102 that I paid $90 for 8 years ago at home which can be used to measure liquids up to 158F. This meter has a separate temperature probe you stick into your sample. Not too long ago certain patents ran out that enable the cheap production of ATC equipped pen style meters, even KegLand has one out now. Some of the cheaper ones only go up to 122F on temperature rating. You won' be able to stick this directly in the mash tun, but it still greatly reduces the amount of cooling required for the sample. Shop around, read spec sheets.

 

[DuncB]

@Indian_villager
I do ensure that no frost interferes with my sample and any condensation is reincorporated before a reading.
My pH meter only cost 15 dollars a couple of years ago. It's not lab grade and my beer isn't made in laboratory conditions.
I was interested in your mention of cleaning solution, which one?
Most of us don't brew every few days and looking after the electrode with storage solution and not letting it dry out is essential along with calibration checking.

 

[DuncB]

I have a MW102 that I paid $90 for 8 years ago at home which can be used to measure liquids up to 158F

So it costs a dollar a brew in ongoing replacement probe costs, assuming 20 brews a year.
I think the most challenging thing is to ensure that the sample taken is a true representation of the whole wort.
I notice this most with gravity checks using my Milwaukee refractometer and I mix and take an average of the various readings.

 

[Indian_villager]

@Indian_villager
I do ensure that no frost interferes with my sample and any condensation is reincorporated before a reading.
My pH meter only cost 15 dollars a couple of years ago. It's not lab grade and my beer isn't made in laboratory conditions.
I was interested in your mention of cleaning solution, which one?
Most of us don't brew every few days and looking after the electrode with storage solution and not letting it dry out is essential along with calibration checking.

Here is the cleaning solution.
https://www.amazon.com/dp/B000EOM4W...=3SDKHWUOZXL53&amp=&sprefix=ph+probe+cleaning

As for uses per year it really depends on what I am brewing, if it is a grain bill+mash profile I've successfully run before I won't bother testing it as I have my process dialed in pretty well with Bru'n Water, I'm usually a few thousandths away from the calculated value. And for the $1/brew I've only replace the probe once in my 5 years of owning the meter, I really used it for the first 2 years I used it, put it away for a while, and now I broke it back out again as I am fidgeting with pH in other parts of my process and playing with kettle souring.

I'm curious about your $15 meter, are you still able to measure your calibration solution after your calibration? As in you do the 7 and 4 pH calibration, rinse off the probe, and then go measure the 7 and 4 pH solutions, do you get a reading that is close? I trashed the probe that came with the meter because it would be off by a decent bit following calibration, but in all reality it did all I could ask for being 5 years old at the time it went to trash.

 

[refect]

I use the Apera Instruments AI311. Whenever I measure my mash ph, I generally stick the sample in the freezer for a bit and take my ph reading once it gets in the 70 degree range. I've taken readings at mash temp, around 100 degrees, and at room temp. All 3 temperatures showed a different ph. My ph meter says it has ATC, but I don't trust it for this reason. This is why I was curious what temp people were tracking the kettle ph since it can vary depending on temperature. I do all my mash ph samples at room temp, but wasn't sure about kettle ph samples. I always calibrate it right before using it, but it looks like it might be good practice to take the sample at the temperature it was calibrated at regardless of the ATC (At least for the cheaper ph meters).

 

[dmtaylor]

I use the Apera Instruments AI311. Whenever I measure my mash ph, I generally stick the sample in the freezer for a bit and take my ph reading once it gets in the 70 degree range. I've taken readings at mash temp, around 100 degrees, and at room temp. All 3 temperatures showed a different ph. My ph meter says it has ATC, but I don't trust it for this reason. This is why I was curious what temp people were tracking the kettle ph since it can vary depending on temperature. I do all my mash ph samples at room temp, but wasn't sure about kettle ph samples. I always calibrate it right before using it, but it looks like it might be good practice to take the sample at the temperature it was calibrated at regardless of the ATC (At least for the cheaper ph meters).

A pH meter that has been calibrated at room temperature will read too low by 0.25 when dunked into the mash at about 150 F. I use this fact in my own brewing -- I measure mash pH directly in the hot wort, then add 0.25 to give a room temperature reading like everybody else, aiming for around 5.5 to 5.65 room temp (or 5.25 to 5.4 at mash temp). There is science out there on this, here are two interesting discussions:

https://www.homebrewtalk.com/threads/will-it-mash-at-ph-5-00.667992/page-2#post-8653242

https://www.homebrewtalk.com/thread...-at-5-2-to-5-6-ph.671764/page-12#post-8803629

 

[refect]

A pH meter that has been calibrated at room temperature will read too low by 0.25 when dunked into the mash at about 150 F. I use this fact in my own brewing -- I measure mash pH directly in the hot wort, then add 0.25 to give a room temperature reading like everybody else, aiming for around 5.5 to 5.65 room temp (or 5.25 to 5.4 at mash temp). There is science out there on this, here are two interesting discussions:

https://www.homebrewtalk.com/threads/will-it-mash-at-ph-5-00.667992/page-2#post-8653242

https://www.homebrewtalk.com/thread...-at-5-2-to-5-6-ph.671764/page-12#post-8803629

Those are some good discussions. Thank you for sharing. I read through some of it, but will have to go through the entire thread. I saw some people saying that they are aiming for a 5.0 - 5.2 kettle ph measured at room temp. When I setup my water profile I use brun water. I know Martin has expressed the recommended 5.2 - 5.6 mash range should be measured at room temp, and is what the estimated pH on his spreadsheet is calculated at.

This is a constant debate on what temperature mash ph should be measured at, but I always see people say the recommended 5.2 - 5.6 should be measured at room temp. If there is a difference of about .25 - .3 at mash temp, that would mean mash ph at mash temp is more in the lines of 4.9 - 5.3 range (which seems really low to me). This is why I started the thread, because I was not sure what most would recommend to measure kettle ph at. The fact that ph changes at different temps makes it hard to say what ph is a good place to aim for unless the temperature is also provided.

 

[day_trippr]

Relish the simplicity: 5.4 at 70°F, done and done, over and out.

Cheers!

 

[shnth]

what kind of kettle/fermenter ph are you aiming for? i am interested in the impact this has on flavour and the other aspects of the beer. i haven't managed to find exactly what i'm looking for in this regard. that is, is a lower ph going to result in a crisper beer vs a slightly higher one?

 

[refect]

what kind of kettle/fermenter ph are you aiming for? i am interested in the impact this has on flavour and the other aspects of the beer. i haven't managed to find exactly what i'm looking for in this regard. that is, is a lower ph going to result in a crisper beer vs a slightly higher one?

I have not really chased kettle ph and post fermentation ph before. I've never really cared as much. I always figured as long as I hit my mash ph, I'm good. Hoping everything else will fall in line. I've made some amazing beers and some pretty good beers all while never bothering with kettle ph. However, I always felt they could be better, no matter how good they were. Hence why I'm now getting interested in kettle ph/post fermentation ph after all these years.

I know getting your boil ph in a certain range can help with break material, clarity/haze stability, hop utilization, and give a smoother bitterness (Or a more harsh bitterness depending on ph). It is my understanding that adjusting it properly can lead to a crisper beer as well. Especially with lagers. It can also brighten up those wonderful hop aromas.

Some of my best IPAs have always been amazing, but hop aromas are not always as bright as I'd like, or sometimes there may be a little bit of astringentcy to the beer that never goes away. I was hoping by adjusting kettle ph and possibly post fermentation ph, I can combat this and possibly make a smoother, brighter, crisper, rounded beer overall.

An example I'll give...I recently made an imperial brown ale that I added hazelnut coffee to (cold steeped and then added after fermentation). The beer was delicious and very drinkable (keg is gone now), but it had a slight harshness/astringency after I added the coffee. I aimed for an FG of about 1.016 - 1.018 to help balance the biterness I was going to get from the coffee, but there was still a bit of harshness from it. I started thinking if I adjusted the ph after adding the coffee, would this have made it better?

I also made an amazing IPA that had a lot of hop burn, but once all that faded there was still a bit of astringentcy that lingered. I figured maybe next time if I messed with my kettle ph and post fermentation ph the final product may not have had that lingering harshness and possibly brightened up those hops a bit.

 

[HighVoltageMan!]

I watch my pH throughout the brewing process. I can tell you that if your mash pH is good, it will generally rise during the sparge, even with RO/distilled water. Typically if I acidify the sparge water with a small dose of 85% phosphoric acid, the result is a stable pH during the sparge.

I aim for a pH of 5.6 at room temperature for the mash. I have measured the mash pH at temperature and at room temperature and have found them to be @ .2 lower at mash temperature. After the sparge with acidified water is done, the preboil pH is about the same as mash. I then drop the preboil pH to 5.1 +/- .05. If you acidify with phosphoric acid, the boil pH will rise slightly, lactic acid will drop slightly during boil (I don't know the reasons behind it, I just observe it).

Pitch pH for lighter beers, including PA/IPA's is @ 5.1. Pitch pH for darker beers are slightly higher and therefore less acid is needed (most times none is needed). The reason for the lower pitch pH is multiple, not least of which is to reduce sharp bitterness, but also a smoother finish beer. A finish pH of 4.5 will have a sharper bitterness than a beer with a pH of 4.2-4.3. Dry hopping will raise pH by as much as .2 depending on how heavy the beer is dry hopped. A high pH on the finish can also lead to a "flabby" finish, the beer just doesn't seem to come together in the end.

Keep in mind the yeast will drop the pH and is strain dependent. Lagers end up @ 4.3. Chico strains end up @ 4.4-4.5. English strains vary , but 4.3 is common. Kolsch and Alt strains are some of the highest acid producers and can drop to 3.9 to 4.1. WLP029 is a strong acid producer and will drop the finish pH to 3.9 when pitched into a 5.2 pH wort. The yeast also have a sweet spot and even if the the pH of the wort is lower, the finish pH will land nearly the same. But when the wort pH is too high, yeast may not be able to drop the pH to it's proper finish pH.

It's important to watch pH beyond the mash, especially if you are sparging with water with some alkalinity in it.

 

[refect]

I watch my pH throughout the brewing process. I can tell you that if your mash pH is good, it will generally rise during the sparge, even with RO/distilled water. Typically if I acidify the sparge water with a small dose of 85% phosphoric acid, the result is a stable pH during the sparge.

I aim for a pH of 5.6 at room temperature for the mash. I have measured the mash pH at temperature and at room temperature and have found them to be @ .2 lower at mash temperature. After the sparge with acidified water is done, the preboil pH is about the same as mash. I then drop the preboil pH to 5.1 +/- .05. If you acidify with phosphoric acid, the boil pH will rise slightly, lactic acid will drop slightly during boil (I don't know the reasons behind it, I just observe it).

Pitch pH for lighter beers, including PA/IPA's is @ 5.1. Pitch pH for darker beers are slightly higher and therefore less acid is needed (most times none is needed). The reason for the lower pitch pH is multiple, not least of which is to reduce sharp bitterness, but also a smoother finish beer. A finish pH of 4.5 will have a sharper bitterness than a beer with a pH of 4.2-4.3. Dry hopping will raise pH by as much as .2 depending on how heavy the beer is dry hopped. A high pH on the finish can also lead to a "flabby" finish, the beer just doesn't seem to come together in the end.

Keep in mind the yeast will drop the pH and is strain dependent. Lagers end up @ 4.3. Chico strains end up @ 4.4-4.5. English strains vary , but 4.3 is common. Kolsch and Alt strains are some of the highest acid producers and can drop to 3.9 to 4.1. WLP029 is a strong acid producer and will drop the finish pH to 3.9 when pitched into a 5.2 pH wort. The yeast also have a sweet spot and even if the the pH of the wort is lower, the finish pH will land nearly the same. But when the wort pH is too high, yeast may not be able to drop the pH to it's proper finish pH.

It's important to watch pH beyond the mash, especially if you are sparging with water with some alkalinity in it.

This is great info! I typically use lactic acid, so I will keep that in mind when monitoring ph during the boil.

 

[Indian_villager]

Y'all I was wrong. I was mixing up pH temperature correction in my head with conductivity curve correction.
https://assets.thermofisher.com/TFS...p-Compensation-pH-Measure-ST-ATCPHMEAS-EN.pdf

All ATC does is offset the calibration curve for temperature, it does not correct pH measured at an elevated temperature to pH at 25°C. That said, we should still be fine measuring at an elevated temperature, just have to correct the target we are gunning for, or just cool to room temperature. My apologies for the confusion.

 

[Indian_villager]

https://www.homebrewtalk.com/thread...-at-5-2-to-5-6-ph.671764/page-12#post-8803629

Thank you for this link. That chart with the affiliated link provide some real useful information to this topic's main question. Seems I have been making 2 errors that cancel out. Error one was assuming that ATC works as overall temperature compensation on the measured value, and error two was measuring at mash temperature. Despite that, turns out the pH I was measuring at mash temperature was well within the target ranges listed on the BYO article linked. Apologies again for the confusion.