Water treatment made simple

Water treatment is usually one of the last subjects approached by home brewers. Most brewers are undoubtedly perturbed by the complexity. Although the chemistry behind water can be quite complicated the application to the brew house is actually reasonably simple.

Beer contains more water than any other ingredient. The quality of the water will undoubtedly have an influence on the quality of the beer. Be warned though, water treatment will polish your final product and allow subtle nuances to be achieved but if you don’t have the rest of your brewing processed nailed it won’t really help that much.

Traditionally local water profiles would dictate what type of beer a brewery could successfully produce.  For example high alkaline water in London would lend itself to dark porters and stouts. Brewers were style bound by the water they had to brew with. Modern chemistry now allows manipulation of base water to best suit the beer style required so brewers aren’t not now bound by these geographical restraints.

We are not going to go into the chemistry in too much detail, if you want to go in depth then Water - A Comprehensive Guide by John Palmer is a very good read. The cause and effect of basic water treatment is much easier to summarise and understand.

First thing to address in your brewing water is chlorine and chloramine. Both are commonly found in drinking water.  Added as disinfectants they are found in differing levels throughout the country. If these are not removed they will react with the yeast during fermentation causing off flavours and taints.

Removal is fairly simple and should be preformed whatever brewing method employed. The easiest way is to either add the required level of crushed campden tablets (1/2 tablet/25L of water) or pre filter your water.

If you are brewing using kits then further water treatments are not necessary.

If you are brewing using grains or to some respect using extracts then further water manipulation can be helpful.

Mash pH is the next area that will need addressing. The most common mistake most novices make is thinking mash pH is related to water pH. Most tap water will have a pH of between 7 and 8. That’s irrelevant though as it’s the alkalinity of the water which, combined with the grain bill, with give you residual alkalinty. This dictates the mash pH.

Alkalinity refers to the capability of water to neutralize acid. This is really an expression of buffering capacity which will result in a residual Alkalinity which will determine your mash pH. The higher the alkalinity the more acid will be required to reach the desired pH. This is usually measured in Calcium Carbonate (CaC03) parts per million (PPM). Levels of calcium and magnesium in your water will effect the alkalinity.

Alkalinity levels vary from week to week so it’s important to check your water regularly. It’s relatively easy to perform a test using a kit like these.  Acid additions can be calculated based on your target pH and your malt bill. Ideal pH range is 5.2 – 5.5 as levels outside these can effect the enzymes and hop bitterness extraction. Dark malts in the mash will lower the pH so less acid will be required. It’s advisable to use a water calculator to work out the correct additions and make life easier. Generally if your water has high alkalinity and you want to brew a pale ale then you will need acid to reduce your pH. Conversely, if you have very low alkaline water (which will generally be soft) you may need to add sodium carbonate to increase your pH when brewing dark beers.

To lower pH you need to add acidify the mash. Normally this is achieved by using acid (AMS or Lactic) or acid malt. AMS will also add sulphates and chlorides so the choice of which ingredient will depend on your target water profile.

Once you have your mash pH in check then you can look at tweaking the other elements in your water. The five elements which are relevant for brewing are Calcium (CA), Magnesium (MG), Chloride (CL), Sulphate (SL) and Sodium (NA).

To get these you can either contact your local water company or use our water analysis service. Unlike alkalinity these values don’t change that often and small changes will have less impact.

Calcium -  Low levels of calcium will cause issues with the clarity and can also cause fermentation problems. Ideal range is 50 – 200 PPM. Calcium can be added to the grain bill using Calcium Chloride and Calcium Sulphate (gypsum). The choice being whether you also want to add sulphate or chlorides.

Magnesium – Usually found in fairly low levels in base water, Magnesium will effect the alkalinity of the water although not nearly as much as calcium. The main purpose of Magnesium is to provide nutrition for the yeast and aid healthly fermentation. Too much will produce astringency so aim for around 10 ppm. Epsom Salts (Magnesium Sulphate) is usually added to increase magnesium and sulphate levels

Chloride/Sulphates – These two elements work together and will accentuate the flavours in the beer. Here it’s the ratio between then which will highlight the malt or the hop flavours in the beer. More sulphate will bring out the hops and bitterness. More Chloride will bring out the malt flavours of the beer. For example a good ratio for a hoppy beer would be 300 ppm Sulphate : 100 ppm Chloride. If you wanted a more malt forward flavour then 100 ppm Sulphate : 150ppm Chloride would work well. You need to get the PPM of either above 100 to really have any effect here. Calcium Chloride, Gypsum (Calcuim Sulphate), Sodium Chloride (Salt) or Epsom Salts (Magnesium sulphate) are usually used to add the required amount of sulphates and chlorides. AMS will also add sulphates and chlorides as it is a combination of hydrochloric and sulphuric acid so and this is the reason you may choose to use lactic acid or acid malt to correct your pH instead of AMS.

Sodium – This can help increase the mouthfeel and fullness but too much can cause a salty flavour to come through. Anywhere up to 100 PPM can be used. Salt (NaCL) can be used to add Sodium and this will also add chlorides. Most tap water has fairly low sodium content but avoid water that has been softened as the softening process adds a lot of salt.

So without even really understanding the complex chemistry behind your water, simple adjustments in the minerals can really help create top quality beers.