Water Treatment

You could easily fill a library with everything that has been written about treating water for brewing beer. There is an old saying that if you ask ten brewers the same question you will get eleven different answers and true to form, many articles contradict each other. For example, you can go online and read about the need to treat your sparge water and then just as easily find an article that says there is no need to treat your sparge water. 


Don’t feel bad about yourself if you feel this subject is too difficult; I once read a post online from a guy who was a professional flavour chemist for over 20 years and even he admitted he doesn’t fully understand it.


I’m not going to use this page to try to list the many different ways brewers go about testing and treating their water. Instead I’m going to show you what I do. It will cost you the equivalent of five or six pints of expensive ale but in return you will have total peace of mind and the certain knowledge that your water treatment is absolutely spot on. But first, let’s look at the background.  

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Water Purification Treatment

As you'll know, long ago types of beer were brewed that suited the water available locally. Water in London and in the home of Guinness is high in carbonates so naturally good stouts and porters were brewed there. The water in Burton on Trent is high in gypsum so the town is well placed to turn out very good bitter and pale ale.  Now, the march of science has not only given us penicillin and false teeth that aren’t made of wood, but has also made it possible for you and I to brew any type of beer regardless of where we live so long as the water is treated correctly.

Chlorine and Chloramines

A cursory glance at a water analysis report from your local water company will show that there are all kinds of weird and wonderful things in our tap water. From a brewing perspective two of these elements, chlorine and chloramines, should be neutralised. This is because they can combine with malt phenols in the wort to create a compound called chlorophenol, which can give our beer a medicinal taste that can closely resemble the liquid antiseptic TCP – once tasted, never forgotten. (In case you were wondering, phenols describe a wide class of chemical compounds – some are very welcome in our beer, others are not. A chemical compound is a chemical substance made up of two or more different chemical elements, such as water, which of course consists of both hydrogen and oxygen.)  So to summarise, we need to get rid of the chlorine and chloramines and the way to do this is by using Campden tablets, which are as cheap as chips and readily available from your homebrew supplier. Simply crush one tablet per fermentation bin of water, using the back of a sturdy teaspoon and a plate. Put the powder in the water, give it a stir and you’re done.

PH of Water

Contrary to a widely held belief, adjusting the PH is not the reason why we treat our water. This is because it is the PH of the mash that influences the quality of the beer, not the PH of the water. The PH of the water and the PH of the mash are not the same because there is some residual acidity present in the grains. This increase in acidity lowers the PH, so the PH of the mash will be lower than the PH of the water.

Painless Water Treatment

Most tap water tends to have an insufficient amount of calcium for brewing pale ales and bitters, so some must be added.  My tap water’s make up is such that I also have to add calcium to the mash when brewing darker beers such as Stouts, Porters and Milds.  Calcium Sulphate and Calcium Chloride are used to achieve this. Most tap water carries too much carbonates for bitters and pale ales, so that level needs to be reduced. The profile of your tap water will probably be quite different from mine.


The whole subject of water chemistry in respect of brewing beer can be horrendously complicated. Some brewers love the subject while most shy away from it. The choice is really up to you. The thought of making sure your water is properly adjusted to contain the right amount of brewing salts to provide the right balance of minerals and essential ions for the type of beer you intend to brew is naturally quite daunting. The answer is simple – get someone else to do it for you.

A few UK homebrew suppliers have for sale an expert laboratory analysis of your tap water. The concept is simple; once you pay your money you receive a self-addressed envelope and a sample bottle. Fill up the sample bottle, send it off to the lab and you’ll receive a full lab report of your brewing water together with the lab’s recommendations of what you should add to your water, and in what amounts, depending on what type of beer you are going to brew.  Additions can include Carbonate Reducing Solution (CRS), Dry Liquor Salts (DLS), Calcium Chloride Flake, Calcium Sulphate and Lactic Acid.

Beer Glass

So, armed with your Campden tablets and your lab report you can go on and enjoy your brewing with the peace of mind that comes with knowing your water treatment is spot on and you’ll never have to try to remember any of the advanced chemistry that sends most of us off to sleep.


Two points of caution to end: Firstly, superb water treatment does not in itself make great beer. You still have to pay attention to the rest of the process. Secondly, have another lab report of your water done every once in a while because water profiles do change over time.