It required an act of Congress to tell us what a craft beer brewer actually is.

For years, the Brewers Association craft beer industry group offered its definition of a craft brewer, using metrics like barrels of production, percentage of a brewery owned by a non-craft brewer and more “traditional” aspects.

However, it changed its barrel-production limit from 2 million to 6 million in 2010 to accommodate the growth of Boston Beer Co. SAM, -1.30% and its Samuel Adams brand. And the trade group changed the “traditional” portion of its definition last year to include pre-prohibition brewers including D.G. Yuengling & Son and August Schell, which have brewed with maize (once deemed non-traditional by BA) throughout their existence.

However, on June 11, Sen. Ron Wyden, a Democrat from Oregon, introduced the Craft Beverage Modernization and Tax Reform Act (S. 1562) that would not only cut excise taxes imposed on brewers, but would finally settle who’s a craft brewer and who isn’t. The text of that bill hasn’t been released yet, but the folks at the Beer Institute, a Washington, D.C.-based beer industry lobbying group, spelled out three of its key effects.

1. It reduces the federal beer excise tax to $3.50 per barrel on the first 60,000 barrels produced by domestic brewers producing fewer than 2 million barrels annually.

2. It cuts that same tax to $16 per barrel on the first 6 million barrels for all other brewers and all beer importers.

3. It maintains the current $18-per-barrel excise tax for any barrels beyond 6 million.

How does this clarify anything, you ask? Simple. Just by the numbers, the folks getting the deepest discounts are those producing 60,000 barrels or fewer a year. Those are your small craft brewers, and they are legion. In Washington state, for example, there were 256 breweries in operation in 2014, second only to the 431 in California. Of those breweries, only one — Redhook in Woodinville, Wash. — topped 60,000 barrels. While Redhook pushed out nearly 150,000 barrels in 2013, second-place Georgetown Brewing in Seattle produced only 52,000. In a corner of the industry in which the smaller players regularly have to compete with larger craft brewers for resources and shelf space, defining “small” is no minor task.

Meanwhile, the cap for that big discount is set at 2 million barrels, which effectively makes it the cap for large craft brewers as well. That’s great news for Redhook, Widmer Brothers and Founders, which the Brewers Association stripped of their craft brewer titles after they sold minority stakes to larger brewers. It’s not so great news for their bigger “craft” competitors, however.

In the craft beer world, that leaves just a few players on the outside looking in. Boston Beer Co. produced 4.1 million barrels of Samuel Adams, Angry Orchard cider, Twisted Tea, Travelers Shandy and other beverages, but crossed the 2 million barrel threshold on beer alone more than five years ago. Yuengling, meanwhile, makes more than 2.7 million barrels of beer and would also be excluded. The third brewer in that gray area — North American Breweries and its Magic Hat, Portland, Pyramid and Genesee — was out of BA’s craft club for importing Labatt’s from Canada, but produced nearly 2.6 million barrels of its own as recently as 2013.

They’re bumped into the 2- to 6-million-barrel mix of small importers (Diageo and its roughly 2.3 million barrels of Guinness and Red Stripe) and contract-brewed national brands (hello, 5.5 million barrels of Pabst products). The rest, the 6 million-and-up club, is made up of the macros: Heineken, MillerCoors, Anheuser-Busch InBev BUD, -6.01% and Modelo-importing Constellation Brands STZ, -2.28% . If Wyden’s bill is approved, that sets 6 million barrels as a hard cap that even the Brewers Association can’t move.

That distinction is incredibly important, considering that Boston Beer’s production in 2009 was roughly half of its 2014 total. That’s an average of more than 20% growth a year. If that pace continues, Boston Beer will be over the 6 million bar in less than three years and, for tax purposes, would be considered a macro.

That’s going to be a big loss for BA, which has already taken a bruising in its quest for a tax break.

The BA spent years promoting its own Small BREW Act against the Beer Institute’s Fair BEER Act. The BA was against giving importers and larger brewers a tax break of any sort, while the BI felt any tax breaks should be as broad-based as possible. As a result, the Brewers Association and Beer Institute had shared members supporting both pieces of legislation in the hope that either would yield a tax cut. The division between the groups remains, with each issuing separate press releases supporting the Wyden Bill. Still, the BI and BA came together to applaud the House version of the bill.

Bemoaning the eventual departure of Samuel Adams from the craft club misses the bigger point of this bill. Craft beer didn’t need a tax break. The number of breweries in the U.S. has grown steadily from 1,447 in 2005 to more than 3,400 today. Craft beer, meanwhile, has grabbed an 11% share of the beer market by volume and a more than 19% share of that same market in dollars. It’s a nearly $20 billion industry that’s grown by double-digit percentage points for the past decade.

It didn’t need the extra money. However, with Anheuser-Busch InBev buying up small breweries and MillerCoors finding success with its BlueMoon brands, craft beer needed a little help differentiating itself from its rapidly improving competitors. By drawing firm lines and forcing the craft beer industry to make tough decisions, Wyden’s bill accomplishes that goal and defines craft in a way that craft brewers couldn’t or wouldn’t. By letting go of a big portion of its past, craft beer can focus on a less contentious, more prosperous future. That isn’t a consolation prize to grouse about: It’s a gift that craft brewers should be far more grateful for.

Jason Notte is a freelance writer based in Portland, Ore. His writing has appeared in The New York Times, The Huffington Post and Esquire. Notte received a bachelor’s degree in journalism from the S.I. Newhouse School of Public Communications at Syracuse University in 1998. Follow him on Twitter @Notteham.