Kettle pH adjustment calculation?

[SanPancho]

curious to know what folks are doing to calculate acid additions for lowering kettle pH. Few times ive done it at home ive just tried to go back and manipulate brunwater software to get where i want it. I then subtract whatever the mash additions were from the new total and then assume the difference is the kettle adjustment.

There a more accurate way to go about that? I do biab with a dunk sparge if that makes a difference.

 

[couchsending]

I think you can find that calculator online somewhere.. or at least a spreadsheet. I feel like I’ve seen it. Maybe the lowdo sight?

 

[ajdelange]

Clearly the best way to do it is the way you would do it with anything else. Find out how much acid it takes to get 1 L (or 1 gal or 1 quart) of the wort to the pH you want and multiply that by the number if liters (or gallons or quarts) you have and add that much acid. To do this you could withdraw 1 L of wort and transfer it to a smaller (that your kettle) pot. Make sure the wort has been well mixed before you do this. Now add the acid you are going to use very slowly and carefully monitoring the pH as you go and keeping track of the total amount of acid being used. If you undershoot (pH goes too low) then simply add more wort until you hit the target keeping track of how much wort you added. At this point you will have a mL of acid per volume of wort number. Multiply that by the volume of wort (including the sample you have withdrawn). The result is the total amount of acid you need which includes the amount of acid you have already added so deduct that and add the remainder to the kettle. Return the measurement sample.

Kunze essentially recommends doing it this way so you might want to see him for more details.

 

[Silver_Is_Money]

What might I inquire is the ideal kettle pH? Is it to be achieved pre or post boil?

 

[ajdelange]

Post and I'll guess 5.0 - 5.4. Don't take that as gospel. I don't have any reference material with me.

 

[couchsending]

What might I inquire is the ideal kettle pH? Is it to be achieved pre or post boil?

Depends on the beer style, yeast, hopping rate, etc.

 

[Silver_Is_Money]

Post and I'll guess 5.0 - 5.4. Don't take that as gospel. I don't have any reference material with me.

I just did some admittedly quick internet searching and found post boil pH results that hovered around 5.0 to 5.2 pH. I have no idea as to the validity of this range, but it did pop up more than once in my quick search.

Edited to match A.J.'s edit.

 

[sixhotdogneck]

What might I inquire is the ideal kettle pH? Is it to be achieved pre or post boil?

Start of boil pH can be from 4.9 - 5.2 or even higher in some cases.

Ideal start of boil pH depends on the desired characteristics of the beer being made.

A lower pH starts to minimize hop utilization but may smooth the bitterness and a higher pH will increase hop utilization but bitterness may be more harsh.

This pH has other effects such as how well protein coagulation occurs (<5 less coagulation), maillard reaction (higher pH increases color formation), how "hard" your yeast have to work (to lower or raise pH to their standard) etc...

http://beerandwinejournal.com/proper-boil-ph/
http://braukaiser.com/wiki/index.php?title=How_pH_affects_brewing
https://homebrew.stackexchange.com/questions/9315/what-is-the-ideal-boil-ph

End of boil may be .1-.3 units lower than start.

You can tell when the boil pH may have been "off" on a beer as it has harsher bitterness, more color and chill haze is prevalent. (Of course it's a preference thing and it's what "makes" the beer what it is, so it really is subjective.)

Now if the mash pH is off and the start of boil pH is correct - well that beer would always be perfect!

 

[SanPancho]

we typically shoot for the 5.0 range in hoppy stuff. non-hoppy, malty and/or other types we typically dont adjust, usually no more than .1 or .2 below final mash ph. in those cases, we just let the yeast do their thing.

i recognize the "correct" method here, which is using the 1L sample and scaling up. but this isnt really something i want to deal with at home. i've used my method noted above and been roughly in the ballpark, but that was adding about 1.5ml to 3.5gals wort. trying to do that in a single liter would be like 0.1ml of acid. sample size is just too small for me to able to deal with that at home... and the process itself would just be slowing down my day.

so the goal is to see if there is in fact some way to manipulate something like brunwater or some other spreadsheet to get a calculated acid addition. while it may not be the "best" way to go in a sense, i think as long as i can start with that number then i can then check and adjust with each brew.

 

[ScrewyBrewer]

Sounds like we've added several more variables into the mix now.

Type and/or style of beer
Amount of hops added to the kettle fermenter or keg

Where would you even start to sort them all out.

 

[ajdelange]

I hope everyone ignored my 4.0 - 4.4 post. That was a typo. It's been corrected.

 

[SanPancho]

well as it turns out, the calculations i noted above turned out to work pretty damn well. i shoot for 5.35 in the mash, and calculated that i'd need an extra 1.5ml of lactic to get me down to about 5-5.1. my OG was a bit off, but volume (3.5g) was right on and final kettle ph- 5.05.

so apparently the estimation/calculation method using brunwater works well enough.

 

[ScrewyBrewer]

well as it turns out, the calculations i noted above turned out to work pretty damn well. i shoot for 5.35 in the mash, and calculated that i'd need an extra 1.5ml of lactic to get me down to about 5-5.1. my OG was a bit off, but volume (3.5g) was right on and final kettle ph- 5.05.

so apparently the estimation/calculation method using brunwater works well enough.

How did you decide that a 5.1 pH was needed for your wort pre-boil? And did you get to check the pH of the finished beer? Can you provide more detail on what you consider to be the ‘final kettle’ pH.

 

[SanPancho]

See op . Im talking about final pH for knockout, not preboil.

 

[ScrewyBrewer]

See op . Im talking about final pH for knockout, not preboil.

So post boil, correct. And why did you feel a 5.1 pH is important.

 

[ajdelange]

Your notes on what has worked for you are going to be the best guide. The fact that what a calculator predicted happens to have worked for you represents a coincidence rather than something you can rely on. A good calculator (i.e. one that predicts mash accurately) has a good model of the acid/base properties of the chemical species in your mash. These are carried over into your wort so that your wort's buffering is going to be pretty close to that of your mash. Such a calculator would be able to predict the pH shifting effect of a further acid addition. That might get you to a target pre-boil pH. If you know how much the pH is going to drop during the boil then you are all set. No calculator is going to be able to predict that last step, however.

 

[SanPancho]

@ajdelange in talking with other brewers it seems some folks have said they get less than .1 drop in the boil, others as much as .2 or .3, no real rhyme or reason to it that i could see. if there is a reason, i'd wager you have a better idea than i.

So post boil, correct. And why did you feel a 5.1 pH is important.

make quite a few lagers and just a bunch of hoppy stuff in general. lagers dont multiply as fast as ale so the acidification is generally less. and dry hops, especially large charges, can create a pretty significant bump up in pH. keeping that final ph closer to 4 than 4.5ish seems to help make the hop flavor pop a bit more. at least to me it does. so starting the ferment a few points lower helps us end in the right neighborhood.

 

[ScrewyBrewer]

....lagers dont multiply as fast as ale so the acidification is generally less.

I’m struggling to understand the point you’re trying to get across here?

and dry hops, especially large charges, can create a pretty significant bump up in pH. keeping that final ph closer to 4 than 4.5ish seems to help make the hop flavor pop a bit more. at least to me it does. so starting the ferment a few points lower helps us end in the right neighborhood.

So in my NEIPA using a generous amount of whirlpool and dry hops I should expect the finished beer to be over 4.5 pH without adding acid post mash?

 

[sixhotdogneck]

I’m struggling to understand the point you’re trying to get across here?

My interpretation is that he believes that lager yeast don't multiply as fast as ale yeast therefore that equates to less acid produced by said yeast.

I would think that yeast just set the level of acidity they need and go from there, no matter how fast they multiply.

So in my NEIPA using a generous amount of whirlpool and dry hops I should expect the finished beer to be over 4.5 pH without adding acid post mash?

It depends on the final beer pH, but dry hopping brings the pH back up by a certain amount per pound of dry hops (about 0.14 units per pound). (I'm not sure if "pounds" is a misprint and it should be "ounces"... I don't know).

 

[SanPancho]

Youll have to do your own research on acidification during fermentation for full answer. I dont recall the specific pathways, but the acidification is related to yeast activity rates. Ales tend to acidify more. In general.

So lagers are generally a bit higher in ph than ales and dumping tons of hops makes it worse. The higher pH tends to mute the hops in the final beer. Hence the desire to acidify in kettle to help keep final number in desired range.

 

[Silver_Is_Money]

I presume that for single infusion while attempting something along the lines of a smooth Bohemian Pilsner I would want a higher kettle pH and for single infusion and something along the lines of a crisp German Pils I would want a lower kettle pH. If so, then why not just mash the former at pH 5.5 or 5.6 and the latter at pH 5.2 or 5.3? (Along with mashing the former at 154-156 degrees and the latter at 148-150 degrees, and varying the mineralization levels and types...)

I guess what I'm getting at is that one kettle pH ideal will not likely suit all beer styles. Any more than one mineralization level would, one hop profile would, one mash pH would, one mash temperature, one yeast, one grist recipe, etc...

 

[SanPancho]

you guys are missing the point. what im saying is that at the end of my process- i.e. super hoppy beer, (especially) lagers- pH is higher than i'd like. so in the middle of the process i add acid to combat the rise from the hops.

has nothing to do with my mash pH. nothing to do with my starting boil pH. i can set those where i want them. but getting the yeast to drop the pH exactly where i want it is impossible in a practical sense.

@Silver_Is_Money see #9. nobody said there is only one "true" kettle pH. this is my process. for heavy hopped beers. especially lagers.

not sure why this is veering off into mash discussions.

 

[ScrewyBrewer]

Youll have to do your own research on acidification during fermentation for full answer. I dont recall the specific pathways, but the acidification is related to yeast activity rates. Ales tend to acidify more. In general.

So lagers are generally a bit higher in ph than ales and dumping tons of hops makes it worse. The higher pH tends to mute the hops in the final beer. Hence the desire to acidify in kettle to help keep final number in desired range.

Ok, I think I'm getting it now. Working the process backward in the highest level terms. Were the optimal pH range of a finished beer style between 4.2 and 4.5 pH additional post mash steps may be required to bring the beer within that range. Depending on the number of hops used in the boil whirlpool and for dry hopping.

@sixhotdogneck brought up a good point. After reading the Scott Janish article which referenced Maye's research I found a November 2017 paper that expanded on Maye's research. Where it was noted the pH rise introduced by dry hops increased with lower temperatures of the 40F to the 67F range. To estimate the pH shift caused by hop additions a brewer would first need to pick an optimal mash pH range for conversion then measure their post mash wort pH.

Then based on the amount of boil and whirlpool hops used and contact time with the wort. An estimation of the pH rise introduced in the kettle needs to be added to the pH rise introduced by dry hopping. Which is determined by the number of dry hops used. And the temperature and contact time used when the hops come into contact with the beer or wort.

 

[ScrewyBrewer]

you guys are missing the point. what im saying is that at the end of my process- i.e. super hoppy beer, (especially) lagers- pH is higher than i'd like. so in the middle of the process i add acid to combat the rise from the hops.

has nothing to do with my mash pH. nothing to do with my starting boil pH. i can set those where i want them. but getting the yeast to drop the pH exactly where i want it is impossible in a practical sense..

I get your point you don't care about mash pH that's clear. But I do. I agree with nearly everything you mentioned don't get me wrong. I just have a hard time not worrying about the pH of my mash during conversion.

As for the pH of your lagers do you have a less subjective explaination than 'higher than I'd like'. It would be helpful if we knew what to look for. Was it a pH measurement or taste that kind of detail is what I'd be interested in knowing. Again I'm not disputing anything here other than controlling mash pH obviously but I am interested in your thoughts on this.

 

[SanPancho]

The difference is that you’re connecting every single dot here with regards to ph. Im only focused on the period from final knockout to final product- i.e the fermentation process and corresponding ph lowering. I dont belive theres a calculator that could possibly make all those calculations. And i don necessarily think its a good idea to think that way. I see it as better to simply set targets- mash, final kettle, final beer. Then use acids/bases to meet those targets. And set those targets for the goals you want from each part- mash, boil, ferment. the process is sequential so i see why it would be easy to link them all together, but i think its unnecessary and impractical.

Not sure the name but theres a Lodo guy here who makes sauergut to acidify his lager/german beers and raves about it. Adjusts his mash, boil, and knockout ph numbers with it. Same principle. Although i dont know if his knockout addition is to combat sry hop creep or just a general preference on his process.

 

[Silver_Is_Money]

..... not sure why this is veering off into mash discussions.

Because concepts do not exist in a vacuum. I.E., they must be integrated into a whole via the application of reason.

 

[Big Monk]

The difference is that you’re connecting every single dot here with regards to ph. Im only focused on the period from final knockout to final product- i.e the fermentation process and corresponding ph lowering. I dont belive theres a calculator that could possibly make all those calculations. And i don necessarily think its a good idea to think that way. I see it as better to simply set targets- mash, final kettle, final beer. Then use acids/bases to meet those targets. And set those targets for the goals you want from each part- mash, boil, ferment. the process is sequential so i see why it would be easy to link them all together, but i think its unnecessary and impractical.

Not sure the name but theres a Lodo guy here who makes sauergut to acidify his lager/german beers and raves about it. Adjusts his mash, boil, and knockout ph numbers with it. Same principle. Although i dont know if his knockout addition is to combat sry hop creep or just a general preference on his process.

What we have traditionally done is as follows:

1.) If using Sauergut, we used it at a rate of 30 ml/kg of malt to drop the pH 0.1, IIRC. This was handed down from Kolbach and is documented in Kunze's text. 30 ml/kg is the boil addition rate (or kettle addition).

2.) Mineral acids were a bit trickier at first. You have to make a few assumptions, one being that the buffering is the same from mash to kettle to knockout. Ultimately, what I settled on was a combination of Brun Water's mash acid calculations and Riffe's mash acid calculations, extrapolated to cover kettle and knockout additions by re-calculating the RA for each step. For instance:

Kettle pH (using Acid) = Mash pH (Measured) + (pH/RA Slope (l/mEq) * RA (mEq/l))

KO pH (using Acid) = Kettle pH (Measured) + (pH/RA Slope (l/mEq) * RA (mEq/l))

where:

pH/RA Slope (l/mEq) = 0.17

RA (mEq/l) = -( Acid Strength (%) * ( Acid Density (kg/l) / Mol. Weight ) * 1000 * ml of Acid ) / Corresponding Volume (l)

It's not perfect because we don't know the actual buffering of the kettle wort or KO wort so we have to assume, but it will get you in the wheelhouse if you need to park the carriage in a hurry.

Because concepts do not exist in a vacuum. I.E., they must be integrated into a whole via the application of reason.

While I am a "sum of all parts" kind of guy as well Larry, in this case it doesn't matter. You can totally disregard the mash and kettle predictions one may develop and just take a reading before knockout and use my approximations from above to get a fairly decent, if not totally precise, estimation of knockout pH.

 

[SanPancho]

Because concepts do not exist in a vacuum. I.E., they must be integrated into a whole via the application of reason.

my original question- how to estimate acid additions for targeting a specific KNOCKOUT pH. not mash. not boil...... knockout. only.

so why the urge to talk about mash? i ask because...

in this case it doesn't matter. You can totally disregard the mash and kettle predictions one may develop and just take a reading before knockout and use my approximations from above to get a fairly decent, if not totally precise, estimation of knockout pH.

so yes, mash and boil pH are related. but disregarded here.

 

[Big Monk]

so yes, mash and boil pH are related. but disregarded here.

For the sake of simplicity, that's a big 10-4.

As someone who has tried to stay current on our Gen I vs. Gen II pH software discussions, I still see the utility in these "close enough for government work" applied science calculations.

We need to remember that not everyone wants the "Hard Science" version of what we talk about, even if this is the Brewing Science forum. I agree with many when they say that the best calculations eliminate errors otherwise unnoticed and that that improves "blind estimations" overall.

Yet I also think that down and dirty, "back of the envelope" style engineering calcs are helpful for some as well, and are welcome here in the Brewing
Science forum, especially when the applied science aspect isn't all the way worked out, as in the case of kettle and KO wort buffering.

Just my opinion. We should steer clear of bombarding every single poster in every single thread here with the latest and greatest in pH estimation. This is coming from someone who absolutely feels that these new estimations are the thing to pursue.

 

[ScrewyBrewer]

The difference is that you’re connecting every single dot here with regards to ph. Im only focused on the period from final knockout to final product- i.e the fermentation process and corresponding ph lowering. I dont belive theres a calculator that could possibly make all those calculations. And i don necessarily think its a good idea to think that way. I see it as better to simply set targets- mash, final kettle, final beer. Then use acids/bases to meet those targets. And set those targets for the goals you want from each part- mash, boil, ferment. the process is sequential so i see why it would be easy to link them all together, but i think its unnecessary and impractical.

All I ask is for some insight on how you determined the best pH in your finished beer. I'm not asking for or expecting a written thesis. Or planning to write some sophisticated formulas. Just a bit more insight than 'higher than I'd like'. If you don't know for certain or don't want to share the thought process that's fine. Some people think mash pH is important while others don't. We can just leave it there.