Despite promising myself that I was not going to worry about water treatment until I had done at least 10 AG brews I just could not help looking into this area further.
I have read a lot of the threads on this and it seems there is a lot of different appraoches - What a surprise!!
I stumbled across some advice on the Brupaks website
It says (sorry for the length of the post):
Before you can start to treat your water you should first contact your water supply company and request the total alkalinity of your water in p.p.m. Unfortunately this is not as clear cut as it should be. Water authorities usually express alkalinity as HCO3 (hydrogen carbonate) whereas the brewing industry uses the traditional CaC03 (calcium carbonate). To use the tables below you will need to know the alkalinity expressed as CaC03. As you will probably have only the HC03 value, you can convert it to CaC03 simply by dividing this figure by 1.22. From this figure it is possible to determine the required amounts of CRS and DLS to be added for all styles of beer. An average Bitter or Pale Ale requires the water to have a total alkalinity of 30-50 p.p.m. and a calcium content of 180-220 p.p.m. If the total alkalinity of your water is below 50 p.p.m. you will not need to use CRS but will most probably need to increase the calcium with DLS.
Example: You are brewing a Bitter and the total alkalinity of your water as CaC03 is 195 p.p.m. In order to bring it within the target range of 30-50 p.p.m. you will need to reduce the alkalinity by 145-165 p.p.m. From the following table you can calculate the amount of CRS to be added. N.B. All brewing liquor should be treated with CRS, not just that used for mashing.
CRS in millilitres per litre
CRS 0.35 0.52 0.70 0.87 1.05 1.22 1.40 1.57 1.75
Alkalinity -64 -96 -128 -160 -192 -224 -256 -288 -320
The table shows that to reduce the alkalinity by 160 p.p.m. CRS should be added at a rate of 0.87ml per litre. Thus for a standard 25 litre brew, which will probably require 30 litres of liquor, 30 x 0.87 = 26mls of CRS should be added. After adding CRS, several minutes standing time should be allowed to release the carbon dioxide produced by the neutralisation of the excess acid.
Now that the carbonate level has been adjusted, you now have to correct the calcium content. Fortunately a close approximation of the amount of calcium present can be obtained by a simple piece of arithmetic:
Original alkalinity in ppm x 0.4 = Calcium in ppm
In the above example you have an original alkalinity of 195 p.p.m. Using the above formula the calcium content can be calculated as follows: 195 x 0.4 = 78 p.p.m.
A typical Bitter requires a calcium content of 180-220 p.p.m. As you already have 78 p.p.m. you will need an extra 102-142 p.p.m. The quantity of DLS required can be ascertained from the table below.
DLS in grams per litre
DLS 0.1 0.2 0.3 0.4 0.5 0.6 0.7 0.8 0.9 1.0 1.1
Calcium 16 31 47 63 94 109 125 141 156 172 188
The table shows that in order to increase the calcium content by 125 p.p.m you will need to add 0.7 grams of DLS per litre.
When making a full mash brew, DLS should be added in two stages:
Stage 1. Weigh sufficient DLS to treat your mashing liquor (e.g. 10 litres x 0.7 = 7 grams). Mix DLS into the dry grains. This is most important as adding it to raw liquor will not affect the mash pH.
Stage 2. Weigh sufficient DLS to treat the balance of the total brewing liquor (e.g. 20 litres x 0.7 = 14 grams). Add to the wort at the commencement of the boil.
Extract brewers should add the total amount of DLS to the wort at the commencement of the boil.
From the above information you should be able to treat almost any water to brew first class Bitters and Pale Ales. Other styles of beer, however, require different levels of carbonate and calcium. These are the recommended alkalinity and calcium levels for the most common beer styles.
Bitter and Pale Ale. Alkalinity as CaC03 - up to 50 p.p.m. Calcium - 180 to 220 p.p.m.
Mild Ale. Alkalinity as CaC03 - 100 to 150 p.p.m. Calcium - 90 to 110 p.p.m.
Porter and Stout. Alkalinity as CaC03 - 100 to 150 p.p.m. Calcium - 100 to 120 p.p.m.
Pale Lager. Alkalinity as CaC03 - up to 30 p.p.m. Calcium - 100 to 120 p.p.m.
Is the above advice too simplistic or has anyone had success following it?
According to Wessex Water my tap water is described as very hard with Calcium Carbonate at 311mg/l but I think I might resort to testing my water before each brew in case this changes. Can anyone recommend which testing kit to use? - one of the salifert ones?
As usual thanks for any advice you can give.
Jim
I have GW's book so I will also check that out.