usually matured for relatively short times (a few weeks to a few months) compared to wine, some of the stronger so-called real ales have been found to develop character and flavour over the course of as much as several decades. In some parts of the world, breweries that had begun as a family business by Germans or other European émigrés grew into large companies, often passing into hands with more concern for profits than traditions of quality, resulting in a degradation of the product. In 1953, New Zealander Morton Coutts developed the technique of continuous fermentation. Coutts patented his process, which involves beer flowing through sealed tanks, fermenting under pressure, and never coming into contact with the atmosphere, even when bottled. His process was introduced in the US and UK, but is now used for commercial beer production only in New Zealand. In some sectors brewers are reluctant to embrace new technology for fear of losing the traditional characteristics of their beer. For example, Marston's Brewery in Burton on Trent still uses open wooden Burton Union sets for fermentation in order to maintain the quality and flavour of its beers, while Belgium's lambic brewers go so far as to expose their brews to outside air in order to pick up the natural wild yeasts which ferment the wort. Traditional brewing techniques protect the beer from oxidation by maintaining a carbon dioxide blanket over the wort as it ferments into beer. Modern breweries now brew many types of beer, ranging from ancient styles such as the spontaneously-fermented lambics of Belgium; the lagers, dark beers, wheat beers and more of Germany; the UK's stouts, milds, pale ales, bitters, golden ale and new modern American creations such as chili beer, cream ale, and double India pale ales. Today, the brewing industry is a huge global business, consisting of several multinational companies, and many thousands of smaller producers ranging from brewpubs to regional breweries. Advances in refrigeration, international and transcontinental shipping, marketing and commerce have resulted in an international marketplace, where the consumer has literally hundreds of choices between various styles of local, regional, national and foreign beers. United States Prior to Prohibition, there were thousands of breweries in the United States, mostly brewing heavier beers than modern US beer drinkers are used to. Beginning in 1920, most of these breweries went out of business, although some converted to soft drinks and other businesses.