Do I have this water thing right?

I've been looking through some of the information here, and I think I've got it down, but I would appreciate some confirmation before I do anything destructive. Here is my well water report:

pH 7.6
Fluoride 0.06
Chloride 2.5
Nitrate <0.05
Nitrite <0.05
Sulphate 9.1
Calcium 53.8
Copper 0.011
Iron 0.019
Magnesium 3.23
Potassium 0.96
Sodium 9.1
Hardness (CaCO3) 150
Alkalinity 150
Total Dissolved Solids 210

not on the report, but-
Bicarbonate 182.3
Carbonate 0.3

So then, to brew a 5 gallon batch of pale ale with 11 pounds of grain, I was planning on adding .6 ml of lactic acid to each gallon of mash water and sparge water, and then adding .5 grams of Gypsum and .4 grams of Magnesium Chloride for each gallon of wort into the kettle. That should give me a finished water profile of Ca 84.5, Mg 15.9, Na 9.1, SO4 82.8, Cl 39.4, HCO3 68.5, Total Hardness 277, Alkalinity 57, RA -13, and SO4/Cl ratio 2.1.

If I understand this correctly, I should add the acid to the mash tun after I've added the water to the mash. And, when adding the salts to the kettle, I should calculate the amount of salts for the volume of wort post-boil rather than pre-boil. Is that correct?

That amount of 88% lactic acid would be sufficient to shift your water pH to 6.1. You will need an extra 0.77 mEq/L (2.9 mEq/gal) to get the water alone to pH 5.5. You then have to consider shifting 11 pounds of grain to pH 5.5. That's 5 kg. Assuming the average distilled water mash pH is 5.75 and that the average buffering capacity of the malt is 22 mEq/kg-pH (a questionable assumption) you would need an additional 5*(5.75 - 5.5)*22 = 27.5 mEq to shift the malt. Assuming you are mashing with 3 gal of water (11.4 L) that's about 2 mEq/L. If you try to get all that with lactic I fear you will have a lactic tasting beer.

I'd suggest diluting 4:1 with RO water (reduces alkalinity to 30) or using straight RO water followed by supplementation of the calcium and chloride with half a tsp each of calcium chloride and gypsum per 5 gal. Then add 2-3% sauermalz to the grist or add the equivalent amount of lactic (or phosphoric) acid to the water.

If you prefer to use the water you have and dispose of the alkalinity with acid just add acid to brewing water until the pH is 5.5 (you can use strips for this) but I think it should probably be phosphoric. This would reduce your alkalinity to 22 (a bit less than you'd have with the 4:1 dilution) and you could then just add 2% sauemalz (or the equivalent lactic acid) to your grist to shift the malt pH. You could also do the .5 grams gypsum addition but rather than adding magnesium chloride I'd use calcium chloride. Calcium is always beneficial. Magnesium not so much so. Calcium at 84 mg/L would drop the pH another 0.1 point or so and put right around where you want to be.

All the salts should go into the water unless you have a specific reason for adding them to the kettle. Sparge water and mash water should be treated the same.

All the foregoing assumes (average grain DI mash pH 5.75) a mostly base malt beer. If you are doing something with lots of roast or burnt malt then the average grain DI mash pH will be much lower than 5.75 and things change. You would need less acid and, in some cases, even base. In those you would not want to remove the alkalinity from the water.

Thanks for this. I would prefer to use the water I have, so I'll be adding phosphoric acid to the water and utilizing sauer malt. As for adding salts to the kettle rather than the mash tun, I've been collecting a higher volume of wort and then boiling longer, which increases my efficiency and creates melanoidin, which seems to have been working well. I thought that since a longer boil would concentrate the salts, I would end up with higher levels than I had intended if the salts were added to the larger volume of sparge water. Would that not be the case?

According to Bru'n Water (if I'm using it correctly), adding that amount of magnesium chloride would bring the Mg level to 19 ppm, well below the 30 ppm threshold. Since it seemed that there was already a healthy amount of calcium in the well water, adding calcium chloride as well as gypsum was increasing the calcium level but leaving the Mg level at 3.2, which isn't in the green zone. Isn't that low a level of Mg pushing the resulting beer toward malty rather than balanced?

Obviously adding more salts will result in higher salt content in the beer. The question is as to how much salt you want. Your goal is to adjust total salts, however you add them, to the point where the beer tastes best. I personally find it easiest to treat all the water the same but that doesn't mean you have to do it that way. Clearly any calcium that you are relying on to participate in lowering mash pH has to go into either the mash water or the mash itself. Calcium added to the kettle may also result in a pH reduction depending on how much phosphate is present.

There's a green zone for magnesium? Malt is about 0.13% magnesium by weight. Each kilo contains 1.3 grams. That's hundreds of mg/L no matter how high your water to grist ratio (within reason). 3.5 mg/L or 26 mg/L in the water itself isn't going to make much difference.

Don't add magnesium unless you want it in there for its flavor effects. There is no minimum Mg level for brewing water since malt provides that to the wort. You can ignore the 'green' indicator if you want. That only signals that the concentration is within tolerance of the target.

Great, thanks. So then I'll add the amount of gypsum and calcium chloride that I would want in the finished volume of beer into the mash and sparge water, and utilize phosphoric acid and sauer malt to get the mash pH in range. I think this is going to work out well.