14/06/2017
by Kenny Campbell

The application of water treatment

Water treatment is all too often not given the attention it deserves by craft and home brewers. Some even justify their lack of understanding by condemning the use of “chemicals”.

If you want to brew beer that is not thin, watery, and lacking in character read on.

The application of water treatment for brewing is actually simple.

Around 95% of beer is water. As a young brewer I was taught that I should taste the water for every brew. The quality of the water you use to brew with will have a direct influence on the quality of the beer. Water treatment seeks to both correct undesirable water content and add in missing desirable content. Think of water treatment as if you were preparing a surface for painting – through preparation will yield the best results.

In medieval times, monks would taste the local water and from that decided whether it was suitable for brewing and indeed which style of beer it might best produce. After almost 40 years of professional brewing, I can taste water and determine at least some of its chemistry but that is no substitute for a water analysis from your water supply company. The standard water analysis will tell you some things and may alert you to a potential problem, but if you ask as well as the standard analysis they should be able to supply you with a list of the ions in their water that are important and you need to know about for brewing, more on this later.

The first treatment you need to consider for your brewing water is the removal of chlorine and chloramine. These are added by water companies as disinfectants. If these are not removed, they will react and cause off flavours most typically a chlorophenolic taste, which is not pleasant. Remember to treat all water involved in brewing not just the mash liquor.

Removal is simple either add the required level of crushed Campden tablets (1 tablet per 50L of water) the active sulphur dioxide diminishes rapidly as it reacts with chlorine and chloramine or alternatively pre filter your water with an active carbon filter.

Next let us look at mash pH – this is most influenced by alkalinity caused by carbonate and bicarbonate and if these ions are in sufficient concentration, you will need to remove them. This is most conveniently done by reacting with an acid. The amount of acid required is directly proportional to the alkalinity of the water the water companies will often express this as the concentration of carbonate (C03) or bicarbonate (HCO3). The aim here is to achieve a mash pH of 5.2 to 5.4. I prefer to use phosphoric acid if acid is needed to treat alkalinity where it is necessary this is because it does not significantly affect the taste or the sulphate chloride balance however other more easily obtained products are available such as, AMS which will also add sulphates and chlorides as it is a combination of hydrochloric and sulphuric acid. I would make any acid addition to the brewing liquor (mash and sparge liquor) not to the mash.

Since alkalinity in water can vary, it is important to check the mash pH as a routine.

I would recommend that you use an online water calculator to calculate all of your additions.

As discussed above if your water has high alkalinity and you want to brew a pale ale then you will need to add acid to reduce your pH. However, if you have low alkalinity you may need to add sodium carbonate to increase your pH when brewing a dark beer. This is because dark malts reduce the mash pH.

With your mash pH under control, you can look at the other important ions in your water. The ions which are relevant for brewing are Calcium (Ca), Magnesium (Mg), Chloride (Cl), Sulphate (SO4) and Sodium (Na).

Calcium – The ideal range is 100 – 200 ppm. Low levels of calcium will cause fermentation and clarification problems. Calcium is most easily added to the mash as Calcium Chloride and Calcium Sulphate (gypsum). The choice being whether you also want to add sulphate or chlorides or both see below.

Magnesium – Not above 10 ppm. Magnesium effects the alkalinity of the water although nothing like as much as calcium. Magnesium provides nutrition for the yeast and so aids healthy fermentation. Epsom Salts (magnesium sulphate) is usually added to increase magnesium and sulphate levels. Personally, I do not like the taste of magnesium and would avoid adding it but would accept natural magnesium below 10ppm.

Chloride and Sulphate – These two ions work together and will determine the flavour and character of your beer. The addition ratio will highlight the malt or the hop flavours in the beer. More sulphate will bring out the hops and bitterness and will create a hard dryness. More chloride will bring out the malt flavours and create a soft sweetness. A possible ratio for a hoppy beer would be 200 ppm sulphate : 100 ppm chloride. If you want more malt flavour then 150 ppm sulphate: 150ppm chloride would work better. As with all brewing taste the result and make alterations if you are not happy. As already inferred, the easiest way to add chloride and sulphate is as calcium chloride and calcium sulphate (gypsum).

Sodium – up to 100 ppm sodium increases the mouthfeel and fullness but too much will cause an unpleasant salty flavour. Common salt (sodium chloride) can be used to add sodium but note this will also add chloride. Avoid brewing with water that has been softened as the softening process adds a lot of salt. Personally I would avoid adding sodium to my brewing water.

In summary.

Obtain a water analysis from your water supply company including the important brewing ions as follows: Calcium, Magnesium, Sodium, Sulphate, Chloride, Hydrogen (pH), Bicarbonate (HCO3)

Then use an online water calculator to help determine what treatments are relevant to your recipe.

Finally taste the result and adjust if not quite right.

Written by our friend George Thompson (Master Brewer & Brewing Consultant)