We've heard these terms, but what is the difference between them? Here's the breakdown...
Macro Brewery: These are the "big guys". These breweries typically produce close to or over 100 million barrels of beer per year. In 2007, Anheuser-Busch produced 104.4 million barrels of beer domestically. Is the quality there? That's up to the consumer, but Anheuser-Busch currently holds over 50% of the market share.
Craft Brewery: These are sometimes confused with "Micro" breweries. Craft breweries are typically smaller, but the term really refers to an approach to brewing rather than the size of the brewery. Craft breweries brew less than 2 million barrels of beer per year and typically brew using traditional methods, without adjuncts such as rice or corn, and strive for a more distinctive flavor rather than mass appeal. The largest craft brewer in the U.S. is the Boston Beer Co., brewer of Samuel Adams.
Micro Brewery: These breweries produce less than 15,000 barrels of beer per year. Since the amount of beer produced is small, distribution of micro brewed beer is very limited, and usually only found in the geographic area that it is brewed in. Examples of local micro breweries would be Pacific Beach Ale House and San Marcos Brewery.
Nano Brewery: A fast-growing segment in the brewing community, nano brewers are typically home brewers who are ready to take their craft to the next level. Because the beer is brewed in very small batches, they usually brew less than 100 barrels per year. While small bottle runs may be done, usually the beer is brewed for kegs or casks. By brewing in small batches and selling their product locally, these brewers hope to attain a following which will lead to bigger brewing runs, and hopefully, graduation to micro or craft brewing facilities.
Hopefully putting a definition to some of these terms will give you an edge when ordering your next brew. Learn all you can about the beer you drink. Contribute what you can to the local beer community. Most of all, enjoy your beer!