What is beer?
In its simplest form, beer is water, hops and sugars extracted from malted grain, to which yeast has been added to ferment the sugars and convert them to alcohol.
It is widely accepted that the brewing of beer was discovered by accident, possibly as long ago as 9500BC. Today, beer is the world's third-most-popular drink, after water and tea.
The source and type of the ingredients used to make beer affect the way a beer tastes. Different varieties of hops produce different aromas and flavours, and levels of bitterness. Even the same variety of hops grown in different locations or in the same location in a different year can contribute different flavours, aromas and bitterness. Hops impart flavours and aromas that can be described as, among many things, floral, tropical fruit, earthy and musky.
The variety, source and seasonal factors can also affect the characteristics that the grain (most often barley) will give the beer. Before being used for brewing, most grain is malted. During the malting process, the grain is wetted then kept warm, to start germination. When the grain begins to sprout it is heated and dried to stop germination. The germination of the grain produces enzymes that will convert starches in the grain into sugars when the brewer "mashes" the grain in hot water. The malting process, including to what extent the grain is heated or roasted after being malted, also affects the taste of the finished beer.
The variety or type of yeast used to ferment a beer can have a huge impact on the flavour and aroma of beer. Broadly there are two types of yeast: ale and lager. Ale yeasts tend to result in a slightly sweeter, more full-bodied beer with fruity aromas and flavours than lager yeast, which produces a cleaner, crisper beer. In general, lager yeasts are used to ferment beer at lower temperatures than ale yeasts. Within the lager and ale yeast families, there are a huge number of yeasts available to brewers that will impart different and sometimes very subtle characters to the beer.
The final essential ingredient in beer is water. Like all the other ingredients, water can have a large bearing on the flavour of the final beer. In general, harder waters with more dissolved salts are better for producing ales, while soft water is favoured for producing lagers. Indeed, some of the world's best-known brewing regions have become renowned for their beers because of their water. Burton-upon-Trent in England is famous for its ales, while the Pilsen (Plzen) region of the Czech Republic is home to what many consider the world's finest pilsner-style lagers such as Pilsner Urquell and Budweiser Budvar (not to be confused with the insipid US Budweiser!).
As well as the four key ingredients in beer, there are many others that may be used to add flavour or aroma to beer, change the colour of the brew or increase its alcohol content. Some of these ingredients have a long history in brewing; other ingredients have emerged more recently after experimentation by homebrewers and microbrewers, keen to try new things.
Just some of these extra ingredients, called adjuncts, include different types of malted and unmalted grain, cane and beet sugar, chocolate, fruit, cocoa, honey, molasses, rice, herbs and spices, and lactose (an unfermentable sugar).
To discover more about the ingredients that can go into beer head to the Homebrew section.