kettle acid adjustments

[oliver]

maybe i can't find this feature, but, is there a function within the water calculator that can estimate for me the amount of acid to add after the mash in the kettle?

Targeting 5.25 in the mash on a pale beer, and trying to target somewhere from 4.8-5.0 in the boil kettle, was curious if the Water Calculator on here can digitally guess and check the amount of acid needed before trying to guess and check in the real world. Or if this feature exists, point me to it, maybe i'm not seeing it.

 

[Donoroto]

In the water calculator, under Acid Additions, pick the kind of acid (e.g. Lactic 88%) and try an amount. Note the amount of change, and try a different amount, until you get what you want.

There is no Automatic version.

 

[oliver]

In the water calculator, under Acid Additions, pick the kind of acid (e.g. Lactic 88%) and try an amount. Note the amount of change, and try a different amount, until you get what you want.

There is no Automatic version.

Yes I know how to use that, it's intended for the mash, but, I think what you're saying is I can use that for both?

example, i'm looking at my calc for this recipe right now and I need 8.8 grams of Citric to hit 5.25 mash pH. If I then change that number to 15.4 grams Citric, it shows 5.00 pH, therefore, I need 8.8 grams in the mash and an additional 6.6 grams in the kettle to get where I need to be?

 

[Donoroto]

Ah, I understand now.

I need to admit that I have never concerned myself with the pH of the wort after the mash. I use the credo "it is what it is". I am not at all confident the calculator will do what you want it to do. Sorry for the distraction.

 

[Silver_Is_Money]

I don't personally think you really want to target 4.8-5.0 pH in the kettle, unless you are measuring pH at boil temperature (which most likely requires sophisticated and expensive commercial grade instrumentation).

Most peer reviewed brewing literature written on this subject indicates ideally targeting 5.0-5.2 pH either pre-boil, during the boil (and usually within the latter stage), or post boil and cooling (with the pH reading measured at room temperature for all three of these timing choices).

Software intended strictly for mash pH adjustment assistance can not (IMHO) be kludged into service for post mash kettle pH adjustment, as the math modeling required is (again IMHO) different.

Additionally, after running actual tests upon it in reducing my well waters Alkalinity, and achieving pH's from ~4 to ~5.6 while doing so, and while using 88% Lactic Acid side-by-side with it as a control, I'm convinced that Anhydrous Citric Acid is demonstrably stronger in acidity at common beer brewing pH's than most software currently presumes (meaning much less is actually needed). I attribute this to errors within published pKa's (and particularly within pKa3) as found in most common sources. A pKa3 of 5.19 seems to bring anhydrous CA in line with my measurements for its acid strength. 5.19 for pKa3 is actually accepted in some literature. But far and away most literature has CA's pKa3 at 6.40.

That said, and additional to the above, above some level CA will ruin the taste of beer. I'm speculating here, and a lot depends upon your volume of Wort, but the huge quantities of Citric Acid which you are mentioning are highly likely going to be tasted (and perceived as a defect) in the final beer.

 

[Mark Farrall]

Have you always done the post boil acidification, or decided to try it and found it produced better results? It's something I'm going to start looking into for my hoppy beers. And have you measured/adjusted post boil? Is it any different?

I'm reading/hearing a bit about post boil acidification for hoppy beers and wondering if it matters when it's done, pre or post boil.

 

[oliver]

Have you always done the post boil acidification, or decided to try it and found it produced better results? It's something I'm going to start looking into for my hoppy beers. And have you measured/adjusted post boil? Is it any different?

I'm reading/hearing a bit about post boil acidification for hoppy beers and wondering if it matters when it's done, pre or post boil.

Yes, post mash / preboil (not post boil) acidification is important for hoppy beers as I'm learning it helps with isomerization and creating better fruity flavors. On the contrary, if the pH is too high post mash, whether that's from too much un-acidified sparge water, or mash ph wasn't low enough in the first place, the isomerization creates flavors that i describe as pencil. I've been talking with a commercial brewer who swears by this, and i'm doing some experiments at home to fine tune this concept, thus why i'm looking for BrewersFriend to help me estimate post mash acid numbers instead of going in too hard on it.

 

[oliver]

also from braukaiser:

Before hop bitter acids can be transformed into their iso- forms, which are more soluble, they need to be dissolved into the boiling wort. That solubility depends on both wort temperature and pH. Except for elevation and equipment dependent variations, the boil temperature is largely constant. But boil pH can easily vary and with it the solubility of hop acids. It has been shown that this solubility increases with pH (see Figure 4) [Briggs, 2004] which is why the bitterness extraction from hops is greater at a higher boil pH. Many brewers, however, have reported that the quality of the bitterness extracted at high boil pH is perceived as being harsher compared to bitterness gained from a boil at a lower pH.

https://braukaiser.com/wiki/index.php/How_pH_affects_brewing

 

[Nosybear]

First, most of the research on beer has been done to optimize macrobrew. That research indicates the optimum ending kettle pH is 5.0 - 5.2. this has little to do with conversion, more to do with clarification and flavor. I find that a lower kettle pH provides a touch of tartness that really improves light lagers, the most researched beers. Adding a bit of lactic acid, primarily to offset the baking soda in the Whirlfloc, gets me into the range. It isn't necessary. I find it improves my light lagers.

 

[oliver]

so then the answer is no. I asked that probrewer and he says he constantly checks pH starting right after the mash, and just slowly doses with acid until he gets it where he wants it.

I tinkered with the water calculator, I tried entering my source water as a my finished wort profile basically, with all the minerality ppm and pH entered, but then without grist and an acid addition entered in the calculator, it still keeps showing me I'm at 5.67, and so I can't even trick it to thinking I'm currently at 5.25 and start entering acid additions to see how much I'd need to further drop it.

 

[Nosybear]

so then the answer is no. I asked that probrewer and he says he constantly checks pH starting right after the mash, and just slowly doses with acid until he gets it where he wants it.

I tinkered with the water calculator, I tried entering my source water as a my finished wort profile basically, with all the minerality ppm and pH entered, but then without grist and an acid addition entered in the calculator, it still keeps showing me I'm at 5.67, and so I can't even trick it to thinking I'm currently at 5.25 and start entering acid additions to see how much I'd need to further drop it.

That's my process: A ml at a time until good.

 

[Silver_Is_Money]

Initial buffering capacities are lab determined for 'pulverized' flour like consistency "Congress" Worts from which one can theoretically squeeze out about 35-37 SG points per pound of grist per gallon. If you on the other hand can only extract out about 28 SG points per pound of grist per gallon as to your typical conversion, then your actual buffering capacity is on the order of ~28/36 = ~0.78 x pulverized grist (or Congress Mash derived) buffering capacity.

Lets say a certain lot of Vienna base malt has a lab rated 'Congress Mash' derived BC of 45 in units of mEq/Kg_pH. For you (meaning at your level of conversion efficiency, and sticking with the above) this would mean a buffering capacity of 45 x ~0.78 = ~35.1 mEq/Kg_pH.

But after the run-off and sparging are complete all you know are your Worts current SG and volume. And there is no further contact or association with the buffering coefficients initial source weight of grist, but rather only the capacity to backwardly infer a theoretical initial grist weight from an inferred conversion efficiency assumption, the SG, and the Wort volume accumulated.... Hmmm...

Well, moving along....

Delta-pH = mEq's/(BC *Kg)

Lets say that via back calculation from SG and accumulated volume and some nominal conversion efficiency you infer a "nominal" grist weight of 5 Kg, and your Wort measures 5.4 pH at room temperature, and you want to get the Wort down to pH 5.1 post boil and cooling.

(5.4 - 5.1) = mEq's/(5 *35.1)
0.30 = mEq's/175.5
mEq's = 52.65

You are using 88% Lactic Acid with an mEq acid strength of 11.14 mEq/mL at specifically 5.1 pH

52.65 mEq's (Wort) ÷ 11.14 mEq's/mL (Lactic Acid) = 4.7 mL of Lactic Acid to add in order to hit 5.1 pH.

But (and this is a big but) the pH would have measurably dropped somewhat across the boil even if you didn't add any additional acid, so 4.7 mL of added acid is clearly going to be noticeably too much. What to do...? Hmmm again! That somewhat seems to be the key. A real "Delta-pH" for calculating our acids contribution can't be established without it. And the real Delta-pH is not 0.30, but rather somewhat less...

 

[Mark Farrall]

So the best a calculator could do would give you an indication of how far you may need to move, but you'd still be sensible to use some sort of iterative acid addition process?

 

[Silver_Is_Money]

So the best a calculator could do would give you an indication of how far you may need to move, but you'd still be sensible to use some sort of iterative acid addition process?

Yes, but for a one shot of acid and done method (as opposed to adding acid in small "hunt and peck" increments) this link to BF's parent forum might help us to infer a better Delta-pH from which to derive our acid addition: https://www.homebrewtalk.com/threads/calculating-the-anticipated-ph-drop-across-the-boil.693152/

 

[Silver_Is_Money]

From the above link:
pH_Knockout ~= 1.86336 + (0.62686 * pH_Pre-Boil)
pH_Knockout ~= 1.86336 + (0.62686 * 5.4)
pH_Knockout ~= 5.248404 (before any acid addition)
(where 'Knockout' = 'post boil and cooling')

Revised and better 'Delta-pH' estimate:
5.248404 knockout - 5.10 target ~= 0.148404 (as opposed to 0.30)

0.148404 = mEq's/(5 *35.1)
0.148404 = mEq's/175.5
mEq's = 26.044902

26.044902 mEq's (Wort) ÷ 11.14 mEq's/mL (Lactic Acid) = 2.34 mL of 88% Lactic Acid to be added
(with this being our best and final guess/answer)

 

[Nosybear]

Empirically: 1 ml of 88% lactic acid solution will drop the pH of 5.25 gallons of boiled wort about 0.2 points. I use Al's "Drop and test" method to get to the 5.0-5.2 range I want my wort.

 

[oliver]

what are the chances that @Silver_Is_Money 's equations can be incorporated into the Water Chemistry Advanced calculator? I'm using his spreadsheet offline, but it'd be nice to see it as a feature in the existing calculator, keeps everything linked together nicely.

 

[Nosybear]

It would be nice to have an "acidification calculator" somewhere: Say tell it you want to reduce 5.25 gallons of boiled wort from 5.4 to 5.2 pH. Or a mash.... Could get complicated, there are a lot of variables in play. Until then, I'll add a ml of acid and re-measure the pH.

 

[oliver]

Could get complicated, there are a lot of variables in play.

seems like it's already been figured out.

 

[Mont Y. Märzen]

so then the answer is no. I asked that probrewer and he says he constantly checks pH starting right after the mash, and just slowly doses with acid until he gets it where he wants it.

I tinkered with the water calculator, I tried entering my source water as a my finished wort profile basically, with all the minerality ppm and pH entered, but then without grist and an acid addition entered in the calculator, it still keeps showing me I'm at 5.67, and so I can't even trick it to thinking I'm currently at 5.25 and start entering acid additions to see how much I'd need to further drop it.

Hey Oliver, greetings from Lafayette!

We've started paying attention to our Pre-Boil pH after talking with J-Ro at Tin Roof. (one of our Dead Yeast members) He counseled us to get below 5.2 for better hop utilization and flavor/aroma shelf-life after packaging. (and I think it helps with clarity too, my hot breaks have been perfect 'egg-drop soup' when I nail this, and I can read text through my gravity samples and finished beers!)

What I do is initially target my RA for the style range (from the More section of the Recipe Editor) as best I can also paying attention to mash pH of course. I use the auto-additon feature in the Water Calc based on my acid type and strength. (we use 85% Phosphoric) As a rule of thumb, lighter beers usually require about 7ml on our system for a 5gal batch. (starting with 9–10gal of full-volume strike doing BIAB/No-Sparge, and an initial source water pH of 8.0–8.66, our local supply via LUS)

After I initially link the Calc to the recipe to pull in my additions, I go back into the Water Calc and change my target pH to 5.2, then calculate the difference between what acid amount it calls for and what I've initially put in at strike. That usually gets me very close. Occasionally I have to dribble another fraction of a ㎖ or so. But I'm usually rounding up anyway, so that is rare. I just manually put that Acid addition in my Other section on my recipe as that also gives me a brew step so I don't forget.

It would be nice if this were incorporated into the Calc though.

*We chose 85% Phosphoric after playing with Lactic and Acidulated malt. While some people caution about dropping out Calcium, we haven't found that to be a problem. (though we routinely target a minimum of 80ppm if not 100ppm Calcium ions for every brew) We bought a gallon of it and I can get you the link if you need, but I'm sure you have access to just about anything for your shop.