Water for Brewing

A Layman’s view

When it comes to all grain brewing, many confusions abound about what to do with the water for brewing.
The simple fact is, you can make good beer by just using the tap water, however If you adjust the water’s chemistry, you can make even better beer.

A brewer alters the brewing water because the normal pH of water is around 7.0 but the enzymes that are in the malt prefer the pH to be 5.2 – 5.6. The enzymes are needed to convert the starch in the malt to sugars. The brewer also wants to put more calcium into the mash. It’s a superhero.

The Brewer can do this in 2 steps:

Step 1 Change the alkalinity of your water to meet the amount your beer type needs.

Step 2 Add the right amount of calcium your beer type needs.

Beer style requirements

Style CaCO3 Calcium
Bitters & Pale Ales 30-50 ppm 180-220 ppm
Mild Ales 100-150 ppm 90-110 ppm
Porters & Stouts 100-150 ppm 100-120 ppm
Pale Lagers 25-30 ppm 100-120 ppm

    Alkalinity CaCO3

    A brewer first needs to know what the alkalinity of the water is, the figure required is the CaCO3 ppm (parts per million).
    Your local Authority can provide you with a water report and while this is useful, it will have other numbers on it as well.
    The information is only a guide and will show the alkalinity as a range because water levels rise and fall all year.
    Buy an alkalinity test kit and test your own water and then you will have no excuse.

    Taking the example of a Pale Ale, desired alkalinity is 40ppm of water. Tap water could read 200ppm per litre of water, so to get it down to 40pmm requires the removal of 160ppm. One method is to use CRS (carbonate reducing solution). 1 ml of CRS removes 183 ppm per litre of water, and all the water that is to be used in the brew needs to be treated. In this example divide 160 by 183 and multiply the answer by 30.


    So we need ~26 mls of CRS

    Tá go bhfuil sé (that’s it).

    All water should be treated with CRS in the HLT, at least 15 mins prior to use.

    Calcium is the superhero


    After the alkalinity of the water has been adjusted you the amount of calcium should be adjusted to match the beer style to be brewed. Calcium will do a lot of great things, it will,

    • Interact with carbonates: Carbonates increase PH, calcium lowers PH.
    • Bind with carbonates forming compounds that will precipitate out of the mash.
    • Protect the amylases from heat inactivation (falling asleep) when in the mash.
    • Help form trub in the boil, neutralising protein, so helps hot and cold break.
    • Aids yeast flocculation by interacting with protein on the yeast cell wall.

    It even helps remove excess oxalate on your brewing equipment to help prevent the build up of beer stone!

    Lets hear it for CALCIUM.

    There are 2 types of calcium sources a brewer likes:

    Calcium Chloride: the chloride brings out the malt flavour.

    Calcium Sulphate: the sulphate brings out the hop flavour.

    The amount of calcium in each of these sources varies from 23% in calcium sulphate to anywhere between 27% and 18% in calcium chloride. So by adding one of these you also add more sulphate or chloride, which is fine depending on the type of beer you want.

    • Adding back Calcium after CRS
    • By using DLS, aka Dry Water Treatment Salts, which are a blend of the various salts.

    Carrying on the example of the Pale Ale, the tap water to start with contained calcium some of which was removed by CRS. To find out how much was left, take the original alkaline number of 200 ppm, and multiply by 0.4.

    200*0.4 = 80ppm.

    This is the amount of calcium left.

    The range for Pale Ale is 180-220 ppm, so 200 ppm is target, and there is already 80 ppm still in the water, so it needs 120 ppm more added per litre of water.

    1 gram of DLS will add 172 ppm per litre of water, so divide 120 by 172 and multiply the answer by the total volume of water to be treated, in our example 30 litres.

    120/172 = 0.6976744*30 = 20.930232.

    So 21 grams of DLS is required.

    Tá go bhfuil sé (that’s it).


    DLS is added in 2 stages:

    Stage 1
    Of the 30 litres to be used only 10 litres might be for mashing, so add a third (7g) to the cold grains before they go into the mash tun.

    Stage 2
    Add the balance of 2/3 (14g) to the boil kettle at the commencement of the boil.


    By following this guide, you will be able to produce good water for brewing.