The unstoppable rise of craft beer has certainly been good for both curious consumers and hopeful entrepreneurs. However, there has been a crucial question that has always dogged breweries and beer lovers: what exactly is a craft beer?

In the UK, a group is trying to define what a craft beer is and is not. The United Craft Brewers (UCB) wishes to “promote and protect the interests of British craft brewers, their beers and beer enthusiasts,” The Guardian reports.

The UCB is made up of founding members Brewdog, Beavertown, Magic Rock, and Camden Town Brewery. Despite this all-star cast, however, craft beer remains a dodgy subject in terms of definition.

For instance, a list of ingredients does not make a craft beer. This is in stark contrast to German beers which have purity laws that they must abide by. Modern brewers have put anything and everything in their beers, from coffee grounds to marijuana, and they are raking it in as a result.

Avery Brewery

Packaging also does not play a role in defining craft beer. Craft beers can be found in kegs, cans, bottles, and, who knows, maybe even PET bottles and cartons in the future. Company size is also not a factor, as seen with Brewdog which is increasing its already considerable 35-bar operation.

The difficulty in putting a definition to craft beer is also caused by the very culture of craft beer brewing itself. Brewers speak amongst each other. Trade secrets are not really trade secrets as they are freely shared to fellow brewers, Entrepreneur reports.

To illustrate, Adam Avery of Avery Brewing Co. in Boulder, Colo., and Vinnie Cilurzo of Russian River Brewing Co. in Santa Rosa, Calif., both found out that they were producing beer with the same name, “Salvation.”

In other industries, lawsuits would be flying out left and right. But in craft beer culture, it is better to collaborate, as evidenced by Avery and Russian River’s joint beer they call “Collaboration Not Litigation Ale.”