Water & Malt & Hops & Yeast

Water, malt, hops and yeast are the four key elements that make beer. This month’s takeover by Fourpure struck me as the perfect time to look more closely at what goes into our favourite drink. Fourpure’s name is a nod to the German beer purity law of 1516, the Reinheitsgebot, which restricted brewers to using only these four ingredients. Now, brewers are rarely so constrained yet nearly all the beers you drink start with these same four building blocks.

Try new beers every month with our discovery club 😍


Everyone knows water is H20, right? Except, what comes out of your tap or straight from the ground is never just that. Water has minerals dissolved in it which give the water different characteristics, commonly described as ‘hard’ or ‘soft’, that are determined by the type of rock it goes through before it enters the water supply. Those minerals react during brewing to enhance different flavours from the other ingredients. Water also contains trace elements such as copper and zinc, which are essential for healthy yeast.

Historically, regional beer styles were determined by the type of water available locally. London porters benefitted from the high levels of calcium carbonate in the water. By contrast, the subtle features of an original Czech pilsner remain in balance because the soft water in the town of Pilsen contains few dissolved minerals.

Burton-on-Trent became known for producing crisp and hoppy ales in the 19th century after the gypsum in the local water was found to enhance the hop flavours. Brewers even add gypsum (calcium sulphate) to water before brewing to achieve the same effect, a process known as Burtonisation.

Most commercial brewers now treat their water in a variety of ways to achieve the water profile needed for the style of beer they are making. That’s why you’ll see a host of styles, in some cases even dozens, all coming from the same brewery, allowing brewers creativity to shine.

Water is the biggest component of beer by weight. It can take anything from five to 20 litres of water to make a single litre of beer. Once you consider the water required to grow the barley and hops, this figure goes up to 60 litres or more. It’s no wonder many breweries get creative when it comes to sourcing and saving water where they can. Staffordshire’s Freedom brewery get all their water from boreholes and filter any waste water from the brewery through reed beds for a truly sustainable system. In 2014, when Fourpure started brewing, they used ten litres of water to produce each litre of beer but have continuously improved and, impressively, now use half this amount.


Malted barley is the heart of beer – giving sugars that the yeast can convert into alcohol and a palette of colours for the final beer.

Barley is a cereal plant that has been cultivated for about 10,000 years. There is a good deal of evidence that our ancestors favoured varieties for making beer over those that made bread. It’s now the fourth most widely grown cereal in the world with around 150 million tonnes grown each year – although not all of this goes into making beer.

Before they can be used for brewing, barley grains must be malted to add flavour and undergo the chemical changes required to extract that all-important sugar. Malting involves partially germinating the barley seed and then roasting it, to stop the germination and remove water, leaving a stable grain which can then be stored. Depending on the length of time and level of heat applied you can produce malts that range from pale to black. The malts used determine the final colour of the beer, from pale gold through to amber, red then onto mahogany and black.

The roasting level also results in different flavours in the malts – lighter malts will have biscuit-y, bready, caramel and nutty flavours. Those in the middle may taste of toffee, toast, or raisins. At the other end of the spectrum, darkly roasted malts will have bitter flavours like dark chocolate, coffee and burnt sugar.

In the brewery, malts are crushed and then cooked with water at around 66ºc which is the perfect temperature for the enzymes in the malt to convert starch into sugar. Depending on the malts used, different quantities of sugar, colour and flavour are extracted. As a rule, the darker the malt, the less sugar and the more colour it will give. Brewers will almost always use a variety of different malts in any one recipe. It may go without saying, but the more fermentable sugars that are released, the more alcohol that can be produced by the yeast. DIPAs and Imperial Stouts may use double or triple the quantity of malt that a regular strength beer would have, which is one of the reasons they cost so much.


Hops are the cone-shaped flower of the climbing plant humulus lupulus – a close relation to cannabis but without the psychotropic effects. Hops provide bitterness, preserving power and a host of distinctive flavours to beer.

Over 100 million tonnes of hops are grown each year and there is an ever-increasing number of hop varieties for brewers to choose from. This variety adds complexity when choosing the perfect hop for any beer recipe. Author and homebrew hero Randy Mosher has an elegant solution in his Mastering Homebrew book which, despite the name, I’ve seen on the shelf of more than one commercial brewery. Mosher divides hops up into ‘personality groups’, such as Noblesse, Britannic, Cascadian and Pacifical; creating some order in the apparent chaos of competing styles.

Breeding isn’t the only factor in hop character with terroir and climate playing as much of a role in hop growing as they do in grapes for wine. Hops that grow in warm areas like the USA will have strong aromas like grapefruit, passionfruit, rose or even bubblegum whereas those from cooler areas like the south of England will produce more subtle aromas reminiscent of grass, black pepper or green herbs and mint.

When hops are boiled with the wort, bitter tasting compounds in them called alpha acids are extracted. The longer you boil hops, the more bitterness goes into the beer, but they will lose their fresh flavours, in the same way as vegetables become flavourless when you overcook them. To counteract this, brewers will add hops at several points in the boiling stage of the brew to strike a balance between the bitter and aromatic qualities.

There are varieties of hops that are exclusively used for bittering (Nugget, Columbus) and others like citrus and tropical fruit-scented Citra, which are used for their aroma. The third type of hops are dual-purpose and can be used in brewing from the initial bittering stage all the way through to adding aroma in the final dryhopping. Centennial is a dual-purpose hop that is well used in craft beer for both its bittering qualities and floral, citrus aromas.


It’s commonly said brewers don’t make beer, the yeast does. If it weren’t for yeast converting sugar into alcohol in the process known as fermentation, beer would be nothing more than an odd tasting soft drink. Amongst all the complex interactions between beers’ simple ingredients, it is key that all brewers remember that yeast is alive and very sensitive to extremes of temperature or pH. It’s also not particularly tolerant to alcohol, with most brewing yeast dying if the ABV goes above 10%.

While there is more variety in the types of yeast than in all the other beer ingredients combined – some breweries will have their own yeast cultures that have been kept alive over decades or centuries – they can be divided into three broad categories; ale, lager and wild.

The choice of yeast is what distinguishes a lager from an ale. Lager yeasts ferment at the bottom of the fermentation tank instead of bubbling away on the top as an ale would. They work best at a lower temperature – around 10-13ºc which is half the temperature most ale yeasts prefer, and they generally give a clean and neutral flavour, allowing the other ingredients to shine through.

Wild yeasts will be familiar to anyone who has tasted a Belgian Lambic, but they are a source of innovation in craft brewing too. Wild Beer in Somerset have been pioneers in the use of British wild yeasts to produce a broad range of sour and funky flavoured beers.

The different yeasts impart many interesting flavours to the beer – fruity aromas like banana and pear come from compounds called esters which are a byproduct of fermentation. Another result of fermentation are phenols, which can be detected by a spicy or clove aroma, typical of a Hefeweizen or Saison. It’s likely yeast has a big role to play in the unusual flavours of Buxton x Omnipollo collab Yellow Belly, a peanut butter and biscuit imperial stout that contains neither peanuts nor biscuits.

Originally published in Issue 13, written by Anna Romper.

Still thirsty? Find more here:

1 thought on “Water & Malt & Hops & Yeast

Leave a Reply

Your email address will not be published. Required fields are marked *

Name *