If Pabst Blue Ribbon is your beer of choice, the next month or two could be a nail-biter. In a battle of the brews, Pabst and MillerCoors are locked in a lawsuit that could determine the fate of the popular alcoholic beverage.

The situation started going sour when MillerCoors, which produces Miller Lite, Coors, and Coors Light beers among other brands, notified Pabst that they would no longer be making and packaging Pabst Blue Ribbon, Old Milwaukee, or Lone Star beers. The two signed an agreement in 1999 that allowed Pabst to distribute beer brewed by MillerCoors, effectively outsourcing the beer-making process. That agreement is set to expire in 2020. While it allows for two five-year extensions, MillerCoors apparently wants out.

MillerCoors is arguing that they no longer have the manufacturing capacity to continue working with Pabst; Pabst is insisting MillerCoors is looking for a way out of the agreement so they can cripple the competition. The company is also adamant that, with its need for 4 to 4.5 million barrels annually, MillerCoors is the only option. They claim MillerCoors rejected an offer for Pabst to lease one of their brewing facilities and that they also offered to extend the deal only if Pabst paid $45 per barrel—a near-triple price increase that the company can’t afford.

As a result, Pabst sued MillerCoors for $400 million and is asking MillerCoors to act in good faith to help find a resolution that works for all parties. The company also claims to have documents proving MillerCoors deliberately closed breweries so it would no longer have the means to supply Pabst.

If the court finds MillerCoors has no further obligation to Pabst, the company will have to do some scrambling to find a way to continue making product. Pabst claims the only other manufacturer with the capacity to brew enough beer to meet their demand is Anheuser-Busch, and they don’t accept contracts to be a supplier.

The jury trial in Milwaukee County Circuit Court is expected to last through November.

[h/t TIME]