What is Residual Alkalinity?

[peebee]

Aww ,cwap. I was right first time, Chris had said the salts get altered "proportionally":

But I already know that won't add up. Ooo look, there was a typo in my earlier thread (said pH4.46 instead of 4.66). Doesn't mean my calculations are right though.

Time I poured me-self a beer.

 

[peebee]

Hey! You rotten lumps. This is all falling about me ears and no-one steps in to bail me out? Well, I do what I usually have to do and did it myself (I think).

Yeap, Calcium (and Magnesium) have a marked effect on pH (I'd always viewed it as a minor secondary effect). Not because Calcium or Magnesium are acids, but because they react with malt compounds in the mash that otherwise act as "buffers". Okay, we can do without that sort of thing, and something I suggested earlier (wrongly!), was covering up the remedy:

There's always the option to put the "hardness" (Calcium salts) stuff in the kettle (skip the mash), but shouldn't come to that. ...

Well, it is coming to that! Out goes the Calcium into the boiler, and cut the Bicarbonate in half ('cos it's no longer having to counter the lower pH due to Calcium added to the mash). The "Estimated Mash pH" now stays between 5.3 and 5.5 (according to Bru'n Water) using 1/2 finished boil volume mash water amount. 2/3, or "Full". Bit of tweaking to get it working across full range and I'll be running with it again. Sorry, it hasn't shut me up yet, an' I'm going to be papping on about it a good while yet ...