Beer ingredient #2: Water

The “What beer is made from” series is deep dive into beer’s four main ingredients and their impact on its flavour. New to the series? Start here.

Of beer’s four main ingredients, the one used in the highest volume by far is water. In fact, water makes up just over 90% of an average pint of beer!

Rather watch than read? Check out the video.

But, not just any water. Water that’s used for brewing is technically called liquor. At a minimum, it must be of pure drinking quality, free from contaminants and contain a small amount of copper and zinc for yeast health.

Water doesn’t just serve as an environment for fermentation though… it can have a significant impact on beer’s flavour in its own right. Primarily because of the minerals it contains and effect they have on the brewing process.

Water chemistry is highly dependent upon location. After rain falls, it travels over different soils, sands and mineral-rich rock deposits, occasionally picking up compounds like calcium or magnesium that alter the local water supply.

Thanks to their geology, three water profiles have emerged as all important in the history of beer.

In this article, we’ll explore each of these profiles, where they’re found, and the styles they best suit. But first, we’ll say a few words on mineral content and pH – two key aspects of water chemistry.

Mineral content

Mineral content tells us if water is best described as “hard” or “soft”, based on the quantity and types of minerals it contains.

Soft water contains very few minerals, while hard water is mineral-rich.

The types of minerals contained then determine whether that hardness is “temporary” or “permanent”. Hardness is considered temporary if the minerals can be removed by boiling, while permanent hardness requires more complex treatments, like reverse osmosis, to remove minerals.

Water containing calcium carbonate is temporarily hard and better suited to certain beer styles than permanently hard water containing calcium sulphate, for example.

But we’ll come back to this in a bit!


pH tells us whether our water is acidic, alkaline or neutral. Pure water has a neutral pH of 7. A lower number indicates acidity, while a higher number indicates alkalinity.

Why does this measure matter?

During the first step of the brewing process, called mashing, malt’s starches are converted to sugars by enzymes within the grains. (Enzymes are molecules that speed up chemical reactions.) But these enzymes can only function within a specific pH range.

Confusingly, it’s not actually the pH of the water itself that matters, but the pH of the water once combined with the grains, as malt can influence mash pH, too. (Yes, this stuff is complex!)

Given its importance, it’s probably no surprise to learn that the pH scale was developed by a scientist… at a brewery!

Now that we know a bit more about mineral content and pH, let’s have a look at our first water profile.

Hard water: Calcium Carbonate [CaCO3]

London, Dublin & Munich all have water supplies that are high in calcium carbonate.

Calcium carbonate dissolves into water that comes into contact with limestone and it makes the water slightly alkaline (heading towards the double digits on the pH scale).

That alkalinity doesn’t interact well with hops. It makes their bitterness astringent and unpleasant.

So, instead of hops, the brewers in these cities focused on malt – and dark malt in particular.

Why? When roasted, dark malt becomes slightly acidic, which helps to balance out the alkalinity of the hard, high carbonate water.

Hence why we’ve got these cities to thank the following dark beer styles: Dublin’s Irish Stout, London’s English Porter and Munich’s Dunkel or dark lager.

Hard water: Calcium Sulfate [CaSO4]

The wells in Burton on Trent in England contain a compound called calcium sulphate, also known as gypsum.

Gypsum makes for crisp, dry and very hoppy beers. Why?

It increases enzyme activity during mashing, enhances fermentation, and encourages yeast to settle. This means that most of malt’s starch is converted to sugar, which is in turn fully fermented by yeast.

With little fermentable sugar left in the finished beer, it’s dry, has good shelf stability and is crystal clear.

Gypsum also accentuates hop bitterness, making it assertive, but not astringent, so a high volume of hops can be used in the brew.

This is why Burton is best known for giving rise to the India Pale Ale – a pale, bitter and hop-forward beer with brilliant clarity and a crisp, dry finish.

Soft water

Sometimes, the best minerals are… no minerals at all!

The water in Pilsen in the Czech Republic, where the Czech pilsner lager originated, contains very few minerals.

While Czech pilsner is highly hopped, its bitterness isn’t over exaggerated by any minerals in the water, for example, so it doesn’t overpower the style’s soft maltiness. This allows the flavours from the local malt and hops to really shine.

Any water, anywhere

Historically, brewers were limited to their local water source.

Hence why certain beer styles developed in certain places – brewers had to produce styles that suited their local water supply.

But around the turn of the 20th century, our understanding of water chemistry changed.  Brewers learned how to alter their water profile, by adding or removing minerals to best fit the styles they wanted to brew.

Want to brew a hop-forward pale ale or IPA, like those from Burton, for example? Simply “Burtonize” your water by adding gypsum.

Today, brewers truly can brew any beer style anywhere.

As you’ve probably gathered, water chemistry is rather complex and this is just a basic introduction. But hopefully by learning more about these different water profiles, the ways that water can impact beer’s flavour are starting to make a bit more sense.

That said though, water’s contribution is only one piece of the puzzle. Beer’s other ingredients – malt, yeast and hops – all play their part.

Next, let’s move on to ingredient #3: yeast.

Discovering Beer is not affiliated with or endorsed by the Cicerone® Certification Program.

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