Imperial Stout water build from DI

[ChzyMnky]

Hello All,

For my next brew (Imperial Stout) I'm going to start digging into water chemistry... My tap water is crap, so I am going to start with store-bought DI water as a base, and build from there. I've been doing some reading on water chem and have been playing around with the Brun Water sheet, and think I've come up with a starting point... The only thing I'm unsure of is the RA, considering it's negative. However, my mash pH prediction is at 5.4, so I don't think it's that concerning...

42.5 SRM

Calcium 57.3ppm
Mag 10.4ppm
Sodium 21.7ppm
Sulfate 41.2ppm
Chloride 38.3ppm
Bicarb 25.6ppm

88% Lactic Acid 0.76 mL/gal

Cations 4.7(meq/L)
Anions 4.7(meq/L)

Mash pH 5.4
Hardness 186
Alkalinity 21 (ppm)
RA -26 (ppm)
S04/Cl 1.08

How's it look? Am I doing something boneheaded?

Thanks for the help!
Eric

 

[ajdelange]

RA is intended for comparing natural waters. It really doesn't tell you much, except in the broadest sense, how to treat the water you have. Forget about it and concentrate on the predicted mash pH.

Other than that the only thing I see that arches an eyebrow is the use of lactic acid and baking soda. The two have offsetting effects and so you would never use both (unless you wanted to get some lactate ion into the beer using lactic acid and use the bicarbonate to neutralize the acidity). As you will have lots of high colored malt you shouldn't need any acid. In fact you might need some base (bicarb would do). It is especially important in such cases to verify that alkalinity is in fact required before deploying it. This is best done with a small test mash.

 

[ChzyMnky]

Thanks for the feedback!

I tried to adjust my water additions based on your advice. I took out the baking soda, added in some table salt, and upped the pickling lime. I'm having problems hitting the target mineral values for "black balanced" without adding too much base (pickling lime or baking soda), so that I need to add the lactic acid to bring the pH back to 5.4. Am I too worried about hitting the target numbers exactly? Would I be better off ignoring some of the mineral targets in order to get my mash pH to 5.4 without the use of an acid?

Anyway, here are my new values.

42.5 SRM

Calcium 57.1ppm
Mag 11.7ppm
Sodium 23.9ppm
Sulfate 46.3ppm
Chloride 36.9ppm
Bicarb 33.2ppm

Epsom Salt 0.45g/gal
Table Salt 0.23g/gal
Pickling Lime 0.4g/gal

88% Lactic Acid 0.76 mL/gal

Cations 4.9(meq/L)
Anions 2.5(meq/L)

Mash pH 5.4
Hardness 191
Alkalinity 27 (ppm)
RA -20 (ppm)
S04/Cl 1.26

Thanks again for the help! I just got a pH meter for the Holidays, so I may try to do a small test mash too...

 

[ajdelange]

I tried to adjust my water additions based on your advice. I took out the baking soda, added in some table salt, and upped the pickling lime.

The pickling lime is a proton absorber too - it has the same effect as the bicarbonate i.e. raising pH and neutralizing the lactic acid (except that the end result is water rather than CO2 gas).

I'm having problems hitting the target mineral values for "black balanced" without adding too much base (pickling lime or baking soda), so that I need to add the lactic acid to bring the pH back to 5.4. Am I too worried about hitting the target numbers exactly?

Yes.

Would I be better off ignoring some of the mineral targets in order to get my mash pH to 5.4 without the use of an acid?

Yes. That has priority. Mineral content has relatively little to do with the way the beer ultimately tastes. This does not mean it has nothing to do with the way the beer ultimately tastes. You must get the pH in the proper range. You may then tweak stylistic ions to refine the flavors.

Anyway, here are my new values.

42.5 SRM

....

Cations 4.9(meq/L)
Anions 2.5(meq/L)

Something is wrong here as cations and anions must always balance exactly when you add anything to RO water which is assumed to be ion free. There should be no way in which your spreadsheet or calculator gives you an imbalance if you add salt, acid or base to pure water.

I just got a pH meter for the Holidays, so I may try to do a small test mash too...

I would recommend that you add calcium chloride to the water at the rate of about 2.5 g (half a tsp) per 5 gallons. Take a quart of that, warm it to strike temp and add about a pound of the grist mixed in as close to the same proportions as you will use in the actual brew. Let it sit for about 15 minutes with stirring and then check the pH or the cooled sample. It will probably be around 5.5 but if your colored grains are more acidic than usual or you have more of them than usual it may be lower and if less acidic or you are using less, higher. If pH falls between 5.3 and 5.6 don't worry further. Just brew. If the pH is too low add a wee bit of bicarbonate and check again. If too high add a wee bit of lactic acid and check again. You will need to be able to scale those acid or base additions to the full mash so you will have to measure them out. A good way is to make a solution as you can then measure in terms of volumes of that solution.

 

[ChzyMnky]

Thanks for the advice, I'll let you know how it all goes!

As for the cations/anions, they become unequal once I add the lactic acid... Not sure why... I have the Dillution Water Profile set to 100% RO water...

 

[ajdelange]

When an acid (under the definition of acid which definitely includes lactic acid) is added to water it releases hydrogen ions which Brun water counts as 'negative bicarbonate' (???) which, if there were such a thing, would have a positive charge (perhaps we should think of the ions as anti-matter bicarbonate ions). Strange as this may seem it could sort of be made to work if the program recognized that net charge must be neutral. To do this it would have to adjust the pH of the mix which would change the ratio of 'anti-bicarbonate' to lactate (in a case with just lactic acid added to DI water) until the charge was 0. This is in fact what happens in the real world except that it is the charges of H+ and Lac- that are balanced. If you add 100 mg lactic acid to a liter of DI water at pH 7 the pH shifts to 3.48 and the balance is Cations (hydrogen) 0.331 mEq/L; Anions (Lactate and a smidgeon of hydroxyl) 0.331 mEq/L. You could try using the spreadsheet to specify 100 mg/L lactic in DI water setting pH to 3.48 to see if you get balance. If you do that says that the program handles lactic acid (a strongish weak acid) properly and then solve acid addition problems by intelligent guessing at the pH (check out https://en.wikipedia.org/wiki/Bisection_method). Excel's Solver will do this for you in spreadsheets that allow it to run. I don't think Brun does because the cells are locked but I am not sure of that.