Well Water vs. Softened Well Water Questions : Alkalinity (as CaCO3) and Buffering Capacity

[Silver_Is_Money]

Perhaps @Buckeye_Hydro can answer these, but they are fully open questions for all to assist in answering:

My two questions are:

1) Does traditional salt and zeolite resin bed softened water nominally exhibit lesser, the same, or greater ppm (mg/L) Alkalinity (as CaCO3) vs. the untreated well water itself?

2) Does traditional salt and zeolite resin bed softened water nominally exhibit lesser, the same, or greater buffering capacity (resistance to change in pH via acidification) vs. the untreated well water itself?

 

[Vale71]

Perhaps @Buckeye_Hydro can answer these, but they are fully open questions for all to assist in answering:

My two questions are:

1) Does traditional salt and zeolite resin bed softened water nominally exhibit lesser, the same, or greater ppm (mg/L) Alkalinity (as CaCO3) vs. the untreated well water itself?

Same.

2) Does traditional salt and zeolite resin bed softened water nominally exhibit lesser, the same, or greater buffering capacity (resistance to change in pH via acidification) vs. the untreated well water itself?

Same.

 

[1HW]

Alkalinity (expressed as CaCO3) is your buffering capacity, so Q1 and Q2 effectively ask the same question. Generally speaking, hard water has higher alkalinity.

From our friends up north:

Having said that, water softeners remove hardness, not alkalinity. To reduce alkalinity, one would use both a water softener followed by a dealkalizer.

 

[Silver_Is_Money]

Same.

Same.

This is as I had always previously expected. But now I'm not so sure. Jump over to my thread in this forum titled "A Sparge Water acidification experiment gone awry" and go to post #9 within that thread to see the major quandary/funk/poser/confusion I've come up with.

 

[Silver_Is_Money]

Alkalinity (expressed as CaCO3) is your buffering capacity, so Q1 and Q2 effectively ask the same question.

This is as I had expected until now. And until now I had presumed both would be close enough to the same to not indicate a major difference when acidifying to reduce alkalinity and also pH. See my post #4 above.

 

[Silver_Is_Money]

I'm beginning to realize how theoretical brewing science and applied brewing science are not always good bed partners. And how the only one that matters in the end is the applied science.

 

[Vale71]

You should always titrate a weak base with a strong acid such as HCl.
If you titrate with a weak acid such as lactic or citric then complete neutralization does not occur and the PH you'll achieve for a given concentration of acid will also be dependent on the association constant of the weak base as well as of the weak acid. Calcium and sodium bicarbonate have different association constant and this explains your results. The amount of HCO3 has not changed but the equilibrium of the reaction with a weak acid changes if you substitue Na for Ca like a water softener does.

 

[Silver_Is_Money]

You should always titrate a weak base with a strong acid such as HCl.
If you titrate with a weak acid such as lactic or citric then complete neutralization does not occur and the PH you'll achieve for a given concentration of acid will also be dependent on the association constant of the weak base as well as of the weak acid. Calcium and sodium bicarbonate have different association constant and this explains your results. The amount of HCO3 has not changed but the equilibrium of the reaction with a weak acid changes if you substitue Na for Ca like a water softener does.

I agree that strong acids are best, as they can be counted upon to fully dissociate, but sans for AMS/CRS use in the UK, over here we use mainly weak acids like Lactic Acid and Phosphoric Acid (whereby I don't have any Phosphoric Acid, but I do have interest in using Citric Acid, which is also a weak acid). I proved to myself that Citric Acid was not detectable taste-wise when I used it in the acidification of my last batch of Kölsch. It is so easy to measure, and does not seem to pose the typical handling related hazards of messing around with liquid acids.

Are you saying in this that although measured Alkalinity (as HCO3-) does not change, the buffering is indeed altered? If so, then calcium and magnesium play a substantial part which has been substantially ignored by specifically sparge pH adjustment assistant software to date.

For now I'm beginning to tentatively conclude that if one treats Citric Acid as if its acid strength is ~13.54 mEq/Gram regardless of the targeted pH (within reason, and for brewing purposes exclusively) their results will be a much better match for reality. And if full dissociation is somehow to be achieved it's strength can be as high as an upper limit of 15.61 mEq/Gram. I had always wondered why my Citric Acid addition to my Kölsch dropped the mash pH way below what I had predicted for its addition. And now I'm beginning to find out why. And I'm also tentatively beginning to believe that dissociation constants do not always appear to do what is traditionally expected/anticipated of them.

 

[Vale71]

My advice to use strong acids was intended for the purpose of titrating a base. Of course if you're treating brewing liquor you should use what is most suitable and convenient for you, no question there.
As for the sparge water PH predictions I think that under normal circumstances it's safe to assume that all the carbonate will come from a mix of calcium and magnesium unless you're using softened water which is a bad choice for brewing in any case and the advice is to avoid it at all cost.

 

[Silver_Is_Money]

My advice to use strong acids was intended for the purpose of titrating a base. Of course if you're treating brewing liquor you should use what is most suitable and convenient for you, no question there.
As for the sparge water PH predictions I think that under normal circumstances it's safe to assume that all the carbonate will come from a mix of calcium and magnesium unless you're using softened water which is a bad choice for brewing in any case and the advice is to avoid it at all cost.

I effectively titrated softened water with fixed quantities of acids, but only because I had a firm belief that its Alkalinity and buffering were the same as for its well water derived source, and thereby I anticipated no difference. pH ~5.33 for softened and pH ~4.60 for well when both receive the same level of acidification is a clear indication of a difference. There was never any intent to brew with softened water, or with my well water.

Either the Alkalinity of softened water is demonstrably greater, or the buffering is altered, or both. And I have no Idea as to which. And what's worse is that (even though there was measurable enough disagreement between software modeled pH projections for sparge water acidification vs the actual outcomes for the softened water, the actual outcomes for softened matched the predicted results far better than the actual well water itself did. This is why I'm in a complete funk.