Workers at a microbrewery that produced the first domestic India pale ale and calls itself America’s “oldest craft brewery” have voted to unionize, joining a small group of unionized craft brewers in the U.S.

Employees at the 123-year-old San Francisco brewer won a March 13 election to form a unit of the International Longshore and Warehouse Union. The workers’ win takes on extra significance given the beer’s iconic reputation in the Bay Area, and the dearth of union presence in the fast-growing craft beer business.

The vote to unionize follows a sometimes-tense organizing effort during which the company allegedly held so-called “captive audience meetings” where management advised workers against organizing.

The union has also filed a pending unfair labor practice complaint against Anchor for telling some employees to remove pro-union pins from their clothes.

Anchor maintained that it has worked collaboratively with the organizers since the process began. The company told Bloomberg Law in a Feb. 26 email that the unionization election offered “the best method by which all workers can express their choice” and said it planned to “respect the results” of the election.

The definition of craft brewery has been in flux in recent years as the industry itself has been evolving, with larger corporations acquiring traditional craft breweries, like Anchor.

Japanese-owned Sapporo Breweries Ltd. purchased Anchor Brewing in 2017.