<P> As of 2007, the brewing industry is a global business, consisting of several dominant multinational companies and many thousands of smaller producers ranging from brewpubs to regional breweries . As of 2006, more than 133 billion litres (35 billion gallons), the equivalent of a cube 510 metres on a side, of beer are sold per year, producing total global revenues of $294.5 billion (£ 147.7 billion). In 2010, China's beer consumption hit 450 million hectolitres (45 billion litres), or nearly twice that of the United States, but only 5 per cent sold were premium draught beers, compared with 50 per cent in France and Germany . </P> <P> The process of making beer is known as brewing . A dedicated building for the making of beer is called a brewery, though beer can be made in the home and has been for much of its history . A company that makes beer is called either a brewery or a brewing company . Beer made on a domestic scale for non-commercial reasons is classified as homebrewing regardless of where it is made, though most homebrewed beer is made in the home . Brewing beer is subject to legislation and taxation in developed countries, which from the late 19th century largely restricted brewing to a commercial operation only . However, the UK government relaxed legislation in 1963, followed by Australia in 1972 and the US in 1978, allowing homebrewing to become a popular hobby . </P> <P> The purpose of brewing is to convert the starch source into a sugary liquid called wort and to convert the wort into the alcoholic beverage known as beer in a fermentation process effected by yeast . </P> <P> The first step, where the wort is prepared by mixing the starch source (normally malted barley) with hot water, is known as "mashing". Hot water (known as "liquor" in brewing terms) is mixed with crushed malt or malts (known as "grist") in a mash tun . The mashing process takes around 1 to 2 hours, during which the starches are converted to sugars, and then the sweet wort is drained off the grains . The grains are now washed in a process known as "sparging". This washing allows the brewer to gather as much of the fermentable liquid from the grains as possible . The process of filtering the spent grain from the wort and sparge water is called wort separation . The traditional process for wort separation is lautering, in which the grain bed itself serves as the filter medium . Some modern breweries prefer the use of filter frames which allow a more finely ground grist . </P>

When did yeast become primary ingredient in beer