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Water Treatment in brewing

Water treatment in brewing is 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 simple. If you need the relevant treatments, we have them all available on the Geterbrewed websites for homebrewers and Commercial brewers.

Water in beer

Around 95% of beer is water. As a young brewer, I was taught to taste the water for every brew. The quality of the water you brew will directly influence the quality of the beer. Water treatment seeks to correct undesirable water content and add missing desirable content. Think of water treatment as if you were preparing a surface for painting – thorough preparation will yield the best results.

In medieval times, monks would taste the local water and decide 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 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. Still, 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.

Where to start with water treatment

The first treatment you need to consider for your brewing water is the removal of chlorine and chloramine. Water companies add these 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 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 the mash.

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

I recommend using 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, you must 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.

What to use

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 is whether you also want to add sulphate or chlorides, or both. See below.
  • Magnesium – Not above 10 ppm. Magnesium affects the alkalinity of the water, although it is 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 wouldn’t say I like the taste of magnesium and would avoid adding it, but I would accept natural magnesium below 10 ppm.
  • Chloride and Sulphate – These two ions work together and will determine the flavour and character of your beer. The addition ratio will highlight the beer’s malt or hop flavours. More sulphate will bring out the hops and bitterness, creating 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, 150 ppm sulphate: 150 ppm chloride would work better. As with all brewing, taste the result and make alterations if you are unhappy. As 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.

Water treatment in brewing starts by obtaining 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)