The microbrewery is a phenomenon which began in the later half of the 20th century in the United Kingdom as a response to  the inevitable homogenization of beers and loss of locally unique ales when larger corporate beer producers purchased older breweries.  In the United States, under President Jimmy Carter, old laws influenced by prohibition were changed to allow for small batch home fermenting and brewing of alcohol in small batch production.  A microbrewery is a beer producer whose focus is on brewing craft beers typically in limited batches.  Thus, larger breweries may produce craft beers as well as the typically small and relatively local and independently owned breweries that are called micro or even nano-breweries whose products are enjoyed for their uniqueness and excellence in flavor, scent, mouthfeel, sight, and finish. In actuality, the microbrewery predates this more recent revival in the past half century.  Many pubs in the British Isles did their own brewing, for instance, and, as mentioned, there are many pubs, bars, beer gardens, and restaurants more currently  producing their own.