The basics of brewing are the same regardless, whether your brewing an extract or all grain beer. You will start with a combination of sugar and water called the wort. Then you will boil your wort and include hops at various times resulting in varying effects on the beer that will be discussed later on. After the boil, the wort will be cooled in preparation for the yeast. Temperature is very important for fermentation because yeast can add undesired flavors depending on temperature. Once the yeast is added, fermentation begins. The wort/yeast mixtured is set aside to ferment for typically a minimum of two weeks. Once this is done, the beer can be bottled with a little extra sugar to carbonate in the bottle or the beer can be kegged and forced carbonated.
Producing your wort can be quite simple when brewing an all extract beer. For an extract brew, the wort is created by combining a malt extract, either dry or liquid, with water. It's as simple as that. Creating your wort from an all grain batch is a little more involved but not incredibly difficult. The process varies depending on the method of mashing used but the basic idea stays the same. Grain is mashed by letting it steep in hot water (typically 155 °F) for and hour. Then the grain is then sparged with hotter water (typically 170 °F) to release the sugar in the grain.
Hops are the bittering agent used in beer and are just as important to the beer as the grain used. There is a huge selection of hops that may be used in your beer. Hops can have varying flavors and provide varying levels of bitterness through the excretion of Alpha Acids when boiled in the wort. The longer the hops remain in the boil, the more bitter the beer will become.
The length in the boil also has different effects on the beer. Hops added at the beginning of the boil are called the "Bittering" hops and are the main controller of the bitterness of the beer. Hops added with around 15 minutes left in the boil are called the "Flavor" hops and impart a hop flavor to the beer. The flavor is a characteristic of the variety of hop used. Finally, hops added for 5 minutes or less at the end of the boil are considered the "Aroma" hops and give your beer a stronger hop aroma. The aroma is also characteristic of the variety of hop used.
As with hops, the type of yeast used is very important for meeting the style of beer you are trying to create. Different yeasts can produce varying flavors in the beer and also have different fermentation characteristics.
The type of yeast used defines the overarching style of the beer. A lager yeast is used to produce a lager. The same goes for an ale. Ales are probably the most common types of beers produced by new homebrewers as the yeast can ferment around room temperature. Examples of ales include Porters, Stouts, and of course, Pale Ales. Lagers typically need to be cooled as the yeast needs to ferment at a lower temperature. The most common lager is the Pilsner but there are many other kinds.