Nanobrewery

A nanobrewery is type of very small brewery operation, often culturally defined by a less than 4 US beer barrels
 [ 124 US gallons (470 l; 103 imp gal)] brew system. They are acknowledged by the Alcohol and Tobacco Tax and Trade Bureau (TTB), and are fully licensed and regulated breweries. Nanobreweries are often on task to grow into microbreweries or brewpubs. There are quite a few breweries and brewpubs that could have been described

at one point in their history as nanobreweries; had the term been invented. One example is Dogfish Head, from Sabco brew system in 1995. As of 2010, they produce 75,000 US beer barrels [ 2,300,000 US gallons (8,700,000 l; 1,920,000 imp gal) ] annually. 

A list of nanobreweries is kept current by a Hess Brewing Co., a nanobrewery from San Diego, California. As of the end of 2010, they list 84 nanobreweries in the United States alone with 51 currently operating, and 33 in planning.

http://www.bayareacraftbeer.com/tag/nanobrewery-festival/