A bill that would allow limited Sunday sales of alcohol in Minnesota is in jeopardy.

Backers of a bill that would allow liquor stores to sell alcohol on Sundays have been rebuffed at the State Capitol for years. So this year, they considered it a victory that even a tiny Sunday sales provision was included in the overall liquor bill.

The measure, which would allow craft beer taprooms to sell growlers (refillable containers that hold half a gallon) on Sundays, sailed through legislative committees. But in recent days the bill has stalled in the Senate Tax Committee. The roadblock? The powerful Teamsters Union.

• Earlier: Feisty craft brewers join Sunday liquor sales debate

Teamster's Union political director Ed Reynoso said the union started lobbying against Sunday growler sales after he learned a company that distributes alcohol and employs members of the union suggested the law would allow them to reopen their labor contracts because of it. He said the union wants to avoid that because it could mean wages, benefits and work hours could all be back on the table.

"As soon as we had an employer raise the potential that they were going to ask for a reopener, I reached out to leadership, I reached out to the Senate Committee chair," Reynoso said. "I notified them of our objections and our concerns."

Reynoso said he showed the contracts to DFL leaders to highlight the importance of removing the Sunday growler sales provision from the bill. He declined to identify the business that requested the negotiations.

State Sen. Roger Reinert, DFL-Duluth, the primary sponsor of the bill that would allow Sunday growler sales is troubled that he has not seen the contract language or learned the identity of the company.

"We don't have a name and we don't have language," Reinert said. "I trust everyone until I have a reason not to, but I would like to see the language and I would like to know who the wholesaler is because my read of this is it's not a repeal of Sunday sales."

Reinert also has been at odds with the Teamsters over his push to allow liquor stores to sell alcohol on Sunday. He said the Teamsters should have raised objections to the bill in committee instead of talking privately with DFL leaders.

"I have been told that those provisions are problematic and unless I'm willing to take them out, which I'm not, then the bill is not moving forward," he said.

Senate Tax Committee chair Rod Skoe downplayed any suggestion that he is holding up the bill because of the Teamster's objection. Skoe, DFL-Clearbrook, said he opposes any form of alcohol sales on Sundays, and he's not sure if he'll hold a hearing on the bill this session.

"None of the provisions would absolutely have to get done this year so we'll see how our schedule develops," he said.

But there will be consequences if the liquor bill doesn't pass. The University of Minnesota would not have the authority to continue selling alcohol at its football stadium. The push to extend bar hours during this summer's Major League Baseball's All-Star game in Minneapolis would stall and taprooms would not be able to open on Sundays at all.

Sunday growler sales are also included in the omnibus liquor bill in the House. That bill is ready for a floor vote, but the bill's author is waiting to see whether the Senate acts on its version. State Rep. Joe Atkins, DFL-Inver Grove Heights, suggested the Teamster's opposition to growler sales will be an issue.

Andrew Schmitt, director of Minnesota Beer Activists, in Minneapolis on Friday, April 11, 2014. Tom Scheck / MPR News

"We generally try to have a liquor bill that is a noncontroversial bill because we're carrying provisions in there for 13 or 14 members so the extent that anything becomes highly controversial, that places it in jeopardy."

The issue is frustrating to members of the Minnesota Beer Activists, who have lobbied for ending the state's ban on Sunday liquor store sales. The group's director, Andrew Schmitt, said he thought allowing growler sales was a compromise.

"We're not going to see any progress and who comes out ahead on that? It's the Teamsters and it's only the Teamsters," Schmitt said. "They have protection for their concerns and the brewers aren't going to get anything addressed and the consumers aren't going to get their needs addressed and the Teamsters have essentially killed the bill."

Schmitt said he intends to encourage the thousands of supporters to make Sunday sales an issue in the upcoming election.