Bicarbonates? Can someone explain...

[Schnitzengiggle]

Inormally build RO water for brewday. This Sunday, I will be brewing 10 gallons of a Saison, my first attempt at the style. I am trying to formulate a water profile that will be "optimum" for the style, after some research I have come up with this profile:

HCO3 350
Ca 52
Cl 20
Mg 17
Na 35
SO4 107
total hardness 454
pH 7.2

I cannot get anywhere near the HCO3 being 350 while keeping my other numbers within the spcified range.

How can I increasde my bicarbonate, without raising my calcium and sulfates too much?

And I am still unable to achieve the higher pH.

Can someone "school" me on this subject?

Any help will be greatly appreciated, if it helps I use TH's spreadsheet, and Kai Troesters (Kaiser's) water spreadsheet.

Thanks in advance.

 

[ajdelange]

You cannot synthesize this water and you have already discovered the reason without realizing it. In any physically realizable water there must be equal amounts of negative and positive charges. The level of bicarbonate you have specified at the pH you have specified along with the other ions you list total 8.6 mEq/L anions but only 5.5 mEq/L cations. To achieve balance you will either have to increase cations (calcium, magnesium, sodium, potassium) or decrease anions (bicarbonate, sulfate, chloride, nitrate) or both.

Increasing the calcium to 100 and reducing the bicarbonate to 311 would balance the profile making it realizable. Water with all the other ions as you have listed and making these two adjustments to bicarbonate and calcium can be prepared from distilled water by adding the following to 5 gallons DI water:

CaCl2.2H20 0.745 g
NaCl 0.032g
CaSO4.2H2O 1.366g
MgSO4.7H2O 3.256 g
CaCO3 3.392g
NaHCO3 2.370g
CO2 2.130g

The concentration errors calculated from these additions are less than 1% for every ion i.e. this is a tight synthesis. Critical in making this work, and what the spreadsheets ignore, is that in order to get bicarbonate in water carbonic acid must be used. That's the way nature does it and if you want to do it you must do the same. IOW, to synthesize this water you must suspend the chalk and then bubble CO2 through the water until it is dissolved and the pH reaches the desired value. Alternatively the water with chalk suspended can be put in a keg under CO2 pressure and shaken until a sample is clear. After that, it is allowed to stand until the pH rises to the desired value.

Clearly, the CO2 business is a PITA. But assuming yougo through with it you will have water with an alkalinity of 254 ppm as CaCO3 and that will raise your mash pH too high. You will then have to do something to get your mash pH into range and whatever means you chose to do that the bicarbonate, which you went to so much trouble to get into the water, will leave it either as CO2 or CaCO3 precipitate or both. So why go to all that trouble?

 

[Schnitzengiggle]

You cannot synthesize this water and you have already discovered the reason without realizing it. In any physically realizable water there must be equal amounts of negative and positive charges--Critical in making this work, and what the spreadsheets ignore, is that in order to get bicarbonate in water carbonic acid must be used. That's the way nature does it and if you want to do it you must do the same-- why go to all that trouble?

Thank you for the simple explanation, and for the suggested profile. Oh that nature, doing things the hard way.

I appreciate your advice, thank you again.