I am clipping this from another source but it explains it perfectly...
A micro-brewery typically uses between a 30 to 60 barrel brew system. The brewery typically only has one brew system, unlike Craft breweries which can have several brewing systems. At a micro-brewery the system will produce about one batch of beer a day to one batch of beer every other day. Several micro-breweries still produce beers on a 15barrel system at the rate of one batch every other day for a total of 3,000 barrels a year. This is 3,000 barrel output is close to the output of a nano-brewery. A nano-brewery usually uses a 7.5barrel systems (1/3 to 1/10th the size of a microbrewery) and produces beer at the rate of a few batches a week. This puts the total output of a nano-brewery at 1,000 barrels per year.
How does this compare to a brew pub? A brew-pub typically produces 15,000 or less barrel of beer each year and 75% or more of the beer is consumed at the pub (not sold to other pubs). A typical brew pub produces beer on a 3-7.5 barrel system at the rate of one batch every few days. This means a brew pub and nano-brewery produce about the same volume of beer each year.
What is a pico brewery? A pico-brewery is smaller than a nano-brewery. The common definition for pico-brewery is a brewery that uses a 1-3bbl system. If a pico brewery produces beer every other day (which is considered very high output for a pico-brewery) they will produce just over 500barrels a year. By comparison this is the 2 day output of breweries like Magic Hat and Long Trail.
How does this compare with a home brewer? First off, the above are licensed breweries. Second, a home brewer is legally allowed to make UP TO 200 gallons of beer each year for personal consumption without acquiring state and federal licensing. At roughly 30 gallons to the barrel, the home brewer can only produce 6.6 barrels of beer each year (a fraction of what Long Trail produces in just 1 batch). Most home brewers produces beer in 5 gallon batches also refereed to as a sixth (1/6) barrel. In addition, most home brewers do not run their brewing equipment every day. Instead a home brewer will make a batch at a rate of every other week or less.
So basically it will be a similar festival when you go to other brewfests..