A typical batch of homebrewed beer is 5 gallons (19L) in size (roughly enough for 2 cases - or 48 12-ounce bottles - of beer), and is produced by boiling malt extract and hops together in a large kettle, then cooling the mixture - called wort - and adding yeast for fermenting. Some enthusiasts brew in far larger quantities, sometimes as a prelude to commercial production.
Advanced homebrewers often prefer to brew "all-grain" batches of beer, by mashing the grain themselves to produce the malt sugars needed by the yeast. Such techniques allow a greater control over the final quality of the beer than malt extract brewing.
During Prohibition homebrewing was very popular, if illegal. Post-prohibition, people homebrew for a variety of reasons. Homebrewed beer tends to be cheaper than commercially equivalent brews, and can be customized to the taste of the brewer. For instance, "hopheads" can hop their beer far beyond what would normally be considered excessive, or fans of bitter, dark beer can create beers that are the antithesis of the commercially dominant American lager[?] style.
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