Lousy water is what you have in the minds of some brewers. In UK it would considered totally suitable with simple treatment.
Hardness of 291, Alkalinity of 273. CA of 61, Mg of 34, Cl of 5.5, SO4 of 20.
So what is your trouble? Alkalinity without doubt, after that----nothing.
What have you got against magnesium? Barley won't grow where there is insufficient magnesium. After malting, barley will supply more magnesium than calcium. Its influence cannnot be as significant as is generally believed.
Hydrochloric acid will, if used in the correct quantity, reduce alkalinity and increase chloride. Many British beers are made with more chloride than sulfate, as are many Czech and German beers. The belief that sulfate means all things to all men is not wise.
I'm not sure if your alkalinity is measured as calcium carbonate or bicarbonate, so won't go any further at this stage, but if you can use your water with hydrochloric acid to reduce alkalinity to about 25ppm as CaCO3 and add another 100ppm calcium using a mix of gypsum and calcium chloride chosen to your taste, then top fermented with your Black Sheep yeast, you might get a pleasant surprise of the taste of a British style pale beer .
Well that's heartening to hear a British brewer say these things, Cire. Sorry, I should have said, hardness and Alk. both as CaCO3. I have never used HCL to bring down alkalinity before (actually, never used it before), so have no idea of its flavor effect, or what its threshold is, actually. So I was worried what even 35-50 ml 10% would be like, so if I have it right, have I coopted your math correctly (don't know if it's linear, actually, the correction - that's how much I need to learn), 273-25 = 248 ppm to reduce; and thanks for walking me through to the end, AJ, so if I go with your 82.4, that's 248/82.4*35 = 105.3 ml of 10% w/v HCL (right, guys)? Going conservatively on this, too, if I have, will allow me to measure as I approach.
Am I right in presuming this should all be flavor neutral, because all I'm doing is cancelling out HCO3? I don't know how much Ca, Mg will be left after this but if I hear you right, Cire, it really doesn't matter - practice would be to add in a total of 100 ppm Ca by some mix of the two salts. My bent is somewhat more to chloride, even though these are bitters, because if I also have it right and my memory serves, my enjoyment in the Northern pales is a wonderful balance of chloride fullness, with hop presence but not overwhelmingly so.
Oh, and need to say, on Mg, nothing (save some rather unpleasant GI effects past a certain amount, lol). I just again don't know what kind of threshold we're talking about before it renders an unpleasant effect. Knowing it would be there in sufficient quantities, too, I think I thought to strip it down almost completely (I think I have it very close to zero, in terms of added contribution, on a 90% RO liquor spreadsheet).
To be honest, I don't have my pH meter any longer, but will be getting one (Hach). I have always been very tight on its use, having used one constantly in both brewing and cheesemaking, but as I've done neither for a long time, I sold my (Extech pH 110, which did fine, if not great) meter quite awhile ago. Truthfully I'm very eager to do up 1 gallon, let's say, drop some HCL in (though I want to work the numbers out myself, just takes a few passes though I know it's been provided above), and measure before and after. Will also look forward to doing hardness and alk. tests after as well.
Any errors in understanding, would appreciate your corrections. Otherwise, many thanks, both of you.