Water profiles: Balancing ions

[StevoTosh]

Hello fellow brewers
I have been experimenting with water profiles in an attempt to find my most preferred profiles for each of the styles I brew.
I tend to keep Ca low (50-60 ppm) but vary Mg and Na. I put more emphasis on the SO4/Cl2 ratio as opposed to their levels.
My starting water profile, the style and finished profile are (I believe) of no consequence to the conundrum that I have been grappling with, which is how to to balance the cations and anions.
A simple way to adjust this balance is to adjust bicarbonate levels. However, according to Bru'n Water and other sources, bicarbonate in the finished water is not relevant and I'm not really sure what that means, but I do know that I have no way of determining bicarb levels in the overall finished profile, and mash Ph adjustments dramatically affect the balance.

So, my question is: Should the ion balance be calculated using the values of bicarb present in the adjusted water profile prior to the mash, negating acid additions and/or other mash Ph adjustments, or am I barking up the wrong tree and missing something here?

 

[VikeMan]

I put more emphasis on the SO4/Cl2 ratio as opposed to their levels.

I would recommend paying attention to both, but with more emphasis on their absolute levels. There's a big difference between [10 ppm SO4/5 ppm Cl] and [100 ppm SO4/50 ppm Cl], even though they have the same ratio. My example is a little exaggerated, for effect.

My starting water profile, the style and finished profile are (I believe) of no consequence to the conundrum that I have been grappling with, which is how to to balance the cations and anions.
A simple way to adjust this balance is to adjust bicarbonate levels.

The (real life) Cations and Anions will always be balanced, no matter what you do. When you add "bicarbonate," you do it by adding a salt, Baking Soda (NaHCO3) for this example, that dissociates into a Sodium ion (Na+) and Bicarbonate ion (HCO3-). Note the positive (cation) charge for the Na+ and the negative (anion) charge for the HCO3-. The total charge remains balanced at neutral, unchanged by the addition of the NaHCO3.

What you are really adjusting by adding "bicarbonate" is pH, not net ionic balance.

However, according to Bru'n Water and other sources, bicarbonate in the finished water is not relevant and I'm not really sure what that means, but I do know that I have no way of determining bicarb levels in the overall finished profile, and mash Ph adjustments dramatically affect the balance.

Bicarbonate levels are quite relevant to pH, including mash pH. Perhaps what Bru'n Water meant is that bicarbonate should never have its own "target" level per se. Bicarbonate (which provides alkalinity) needs to be taken into account when computing mash pH and the additions (acid or otherwise) needed to shift mash pH into the desired range. And baking soda (which contains bicarbonate) might be needed to raise mash pH in some cases. So, from a pH control perspective, bicarbonate is something to (usually) be overcome, but is sometimes used as an addition. But there's no particular "level" to target from a flavor/mouthfeel perspective (like there might be with Cl and SO4).

So, my question is: Should the ion balance be calculated using the values of bicarb present in the adjusted water profile prior to the mash, negating acid additions and/or other mash Ph adjustments, or am I barking up the wrong tree and missing something here?

You don't really ever need to calculate ion charge balance, because the charges can never be unbalanced. When you add acid (to lower pH), the acid (no charge), the bicarbonate (negative charge), and some positively charged cation will be used up (transformed) in a chemical reaction that results in a lower pH, but an unchanged overall neutral ionic charge.

IMO, The only time to care about ionic charge balance is when looking at someone's published (notional) water profile, which could (potentially) be unbalanced charge-wise, meaning that it can never actually be built.

 

[StevoTosh]

I would recommend paying attention to both, but with more emphasis on their absolute levels. There's a big difference between [10 ppm SO4/5 ppm Cl] and [100 ppm SO4/50 ppm Cl], even though they have the same ratio. My example is a little exaggerated, for effect.



The (real life) Cations and Anions will always be balanced, no matter what you do. When you add "bicarbonate," you do it by adding a salt, Baking Soda (NaHCO3) for this example, that dissociates into a Sodium ion (Na+) and Bicarbonate ion (HCO3-). Note the positive (cation) charge for the Na+ and the negative (anion) charge for the HCO3-. The total charge remains balanced at neutral, unchanged by the addition of the NaHCO3.

What you are really adjusting by adding "bicarbonate" is pH, not net ionic balance.



Bicarbonate levels are quite relevant to pH, including mash pH. Perhaps what Bru'n Water meant is that bicarbonate should never have its own "target" level per se. Bicarbonate (which provides alkalinity) needs to be taken into account when computing mash pH and the additions (acid or otherwise) needed to shift mash pH into the desired range. And baking soda (which contains bicarbonate) might be needed to raise mash pH in some cases. So, from a pH control perspective, bicarbonate is something to (usually) be overcome, but is sometimes used as an addition. But there's no particular "level" to target from a flavor/mouthfeel perspective (like there might be with Cl and SO4).



You don't really ever need to calculate ion charge balance, because the charges can never be unbalanced. When you add acid (to lower pH), the acid (no charge), the bicarbonate (negative charge), and some positively charged cation will be used up (transformed) in a chemical reaction that results in a lower pH, but an unchanged overall neutral ionic charge.

IMO, The only time to care about ionic charge balance is when looking at someone's published (notional) water profile, which could (potentially) be unbalanced charge-wise, meaning that it can never actually be built.

Now this makes sense. Thank you.
You have answered many of my concerns.
I can chase my preferred Ph freely, regardless of the fact that some brewing calculator may tell me that the ion balance is wrong... it has to be right... right?
As for the SO4/Cl ratios and quantities, your info is enlightening to such a degree that I feel I must do some more experimentation. Trial and error (or success) is my main avenue of advancement.

 

[VikeMan]

I can chase my preferred Ph freely, regardless of the fact that some brewing calculator may tell me that the ion balance is wrong... it has to be right... right?

Right. If a calculator is telling you that the ion balance is wrong, one of these things is happening:

1) The starting water profile was not real.
2) The water contains uncommon/minor ion species that were not measured (or the calculator doesn't include them). Potassium is a possibility here.
3) There's an error in the calculator.

If the error only pops up when you add a salt (for example), it's #3.

 

[mabrungard]

The water profiles in Bru'n Water include a bicarbonate concentration that only serves to balance the cations and anions.

The reason that I recommend that anyone using a given water profile ignore the bicarbonate content, is that you should rely on hitting an appropriate mashing pH and not worry about the bicarbonate content.

Let it go!