The brewery was founded in August 2000 by Nico Freccia and Shaun O’Sullivan. The two had developed the idea for 21st Amendment brewery while attending a brewing class together at UC Davis. O’Sullivan had previously worked as an assistant brewer at
Triple Rock Brewery & Alehouse in
Berkeley, 20 Tank Brewery and Steelhead Brewing in San Francisco. The
San Francisco Business Times wrote that it "made a name for itself as a local brewery and restaurant where
SoMa techies could lunch and
Giants fans could gather before a game." It has been voted "Best Brewpub", "Best Burger" and "Best Happy Hour" by the San Francisco Press. Prior to 2015, 21st Amendment's retail beers were canned in
Cold Spring, Minnesota. In 2012, 21st Amendment planned to case 45,000 barrels of beer, up from 28,000 in 2011. The production brewery started brewing in 2015 and currently has capacity at 150,000 - 180,000 barrels. In 2018 the company was named by the
Brewers Association the 26th largest craft brewery in the United States. In 2023, 21st Amendment Brewery expanded its operations to include co-packing services for other beverage brands. The expansion featured the installation of a packaging line, along with a DC Evans tunnel pasteurizer. On September 4, 2025, 21st Amendment Brewery announced it would be going out of business and shutting down its San Leandro brewery and San Francisco brewpub by November 4, 2025. Freccia and O'Sullivan stated that the business never recovered from COVID-19 with the San Francisco location down by 60% compared to 2019 and a 20% decline in overall company sales every year since 2021. Other factors include drinking in the U.S. being at a 90-year low, stiff competition from beer alternatives like hard seltzers, the San Leandro facility never utilizing full manufacturing capacity even with co-packing for other brands, and numerous distribution problems from the loss of nationwide agreements with
Brooklyn Brewery to a dispute with a can supplier that restricted how much it could sell to being forced to use less favorable
Anheuser Busch networks after its old local distributor DBI Beverage Inc. was bought out by
Reyes Holdings, who dropped 21st Amendment. Furthermore, a planned overhaul of the company was cancelled by a lender who backed out of funding the plans. ==Beers==