Residual alkalinity of HK water

Based on 2023-2024 water report.

Milliequivalent/L bar graph:

from Brunwater:

Residual Alkalinity = 27 - (( 13 + (1.5)/2)/3.5) = 23.07 ppm ( or mg/L) as CaC03

From braumagazin, in °dH:

Calculations are just the same, but units are in °dH. It uses Karbonathärte "carbonate hardness" instead of alkalinity 

Residual alkalinity:

The carbonate hardness bound to hydrogen carbonate (HCO 3 - ) is an alkaline reaction, thus reducing the acidic reaction of the malt and thus increasing the residual alkalinity.

Calcium and magnesium counteract this, because these ions lead to the release of additional acid in the mash. 

If the acidic reaction of calcium and magnesium is stronger than the alkaline reaction of the hydrogen carbonate, the residual alkalinity is lower and even negative. 

This is exactly what we take advantage of when adding brewing salts such as calcium sulfate (brewing gypsum).

Rule of thumb for Lager:

A favorable ratio of carbonate hardness to non-carbonate hardness occurs at 1 : 2–2.5.

I feel sorry not using J Palmer's calculations, as I had a hard time following his conversions of units.

Reference:

Braumagazin

Braukaiser. use GH and KH tests with excel. Simple is the best

Homebrewtalk

ResAlk chart

HK water report 2023-2024

Brunwater

Beersmith

Modernbrewhouse

Lenttech online converter. Very handy