Ever Wondered How Beer is Made? The Science of Beer.

Ever Wondered How Beer is Made? The Science of Beer.

By Matt Kirkegaard - Editor of Australian Brews News

While wine making conjures up visions of vineyards on misty morning and oak barrels silently aging, brewing tends to conjure up factories and giant stainless-steel vats. Beer has a more industrial feel to it that isn't always warranted.

Like wine, beer is a complex agricultural product that brings nature and science together to create the drink we love.

While in wine, once the grape is grown the winemaker nurtures it to become the best wine possible, beer requires quite a bit of added work before the ingredients are even ready to ferment.

Beer also has more than one key ingredient that affects the flavour and the final beer style.

So let's take a little look at what goes into making beer.

Beer has four main ingredients: malt, yeast, hops and water. To make anything alcoholic requires fermentation, and that involves yeast and sugar. In wine, the sugar comes from grape juice. With beer, the sugar can come from a variety of grains, primarily barley.


Unlike grapes, the sugars in the grain are too complex for the yeast to transform into beer. They are too big for the yeast to metabolise. To be useful to the brewer, the starches in the grain need to be broken down into simpler sugars, so the yeast can eat them during brewing. This process is called malting.

Malting involves wetting the grain so it germinates, and enzymes start the process of breaking down the sugars into simple sugars. When that happens, the maltster dries the grain out. They can just dry it and leave the malt pale or toast it a little so flavours such as caramel, toffee, chocolate and coffee develop, which can add different flavours to the beers down the track.

Philter Red Session Ale is an example of the colour malt can bring to a beer, without getting too full on in flavour. The redness comes from the crystal malt which also delivers a light toffee note that pairs with the medium bitterness to finish, making this a ripper of a session ale.

A bolder malt flavour can be seen in Hawkers Stout, which has a rich, dark colour with a full body with flavours of chocolate and espresso that's complex, indulgent and magnificent!


Yeast is a single cell organism, a type of fungus. It's a miracle worker that eats simple sugars and creates carbon dioxide, alcohol and some flavours.

There are two main types of yeast - ale yeast and lager yeast. Ale yeasts tend to ferment best at warmer temperatures (above 15 C) while lager yeasts will work at much colder temperatures. Lager yeasts leave beer with a much cleaner and crisper flavour while ale yeasts give beer a variety of fruity and spicy flavours.

For a long time, one of the only ales most Australian drinkers could get was Coopers Sparkling Ale, with yeast esters that remind us of tinned apricot and tropical fruit. Matilda Bay Redback is a stories craft beer that has recently been resurrected. It highlights yeast characters of banana and lemon curd in a refreshing but full-flavoured ale.


Hops are flowerlike cones that grow on a climbing vine. In the middle of each hop cone are little glands that contain resins and oils. These can contribute flavour, aroma and bitterness to beer.

There are a wide range of hop varieties, each with their own unique characteristics and each adds something different to a beer. Over the last thirty years, the craft brewing movement has really brought hops to the front and centre of brewing.

One of the most distinctive hop characters is tropical fruit. In a beer such as Stone & Wood's Pacific Ale, many drinkers get strong notes of passionfruit and lychee aromas, but no fruit was harmed in making the beer, it's all from the Australian developed Galaxy hops.

Balter Easy Hazy is another top example of hop flavours with fresh passionfruit, lime and bright, breezy coconut on the nose...again all from the hops that flavour this sessionable tropical refresher.


Water is a vital ingredient in beer, making up more than 90 per cent of the finished product and being used in every step of the brewing process. The chemistry of the water is critical to the successful brewing of many beer styles.

In the pre-industrial age, brewers used the water they had available and brewed their beers to fit what they had. However modern brewers can create the precise water they want to perfectly match the beer they are brewing, playing with certain factors such as pH and minerality.


In addition to malt, brewers sometimes use other forms of fermentable sugar for a variety of reasons. Sometimes these are to lighten the body of the beer, sometimes it is to add flavour. With the craft beer renaissance, brewers are rediscovering a huge variety of ingredients that can also be added to beer to accentuate and complement some of the beer's naturally occurring flavours, including the likes of honey, fruit, coffee and chocolate.

The Brewing Process

Beer begins with a recipe, with the brewer selecting what variety of the four main ingredients they wish to include and any adjuncts. The brewer has a vision of how they want the beer to taste and sets about planning to make that a reality.


The malt is crushed and mixed with hot water to form a mash. The mash is left at a temperature of about 65 C for up to an hour during which the enzymes that were developed in the malting process break down the starches into simple sugars that can be metabolised by the yeast. The sweet liquid, the blend of sugars and water, that results from mashing is called wort.


The wort is drained off the spent grain and is moved to the kettle where it is boiled. This process has several roles, including killing any bacteria and other yeasts that might compete with the brewer's choice of yeast and potentially spoil the beer.

During the boil, the hops are added and the insoluble alpha acids in the hops isomerise, producing bitterness in the beer.


The hopped wort is rapidly cooled on its way to the fermenter. Yeast is added to the sugary wort and the 'miracle' of fermentation commences.

Lagers tend to ferment for longer than ales and the process takes up to ten days to complete.

With sugar being the food for the yeast, more food means more alcohol at the end of the fermentation. Alcohol in beer is measured by volume, so in a 5% beer, 5 per cent of the finished volume of beer is alcohol.


Depending on the brewery and beer style, the beer can go through a variety of processes on its way through packaging in kegs or bottles and cans. Cans have increasingly become popular over the last few years as they are lighter, have more space for great design and can also look after a beer a little better than bottles.

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