The latest flashpoint between Texas beer lovers and state beer law is a 32-ounce aluminum can that bars and restaurants fill with beer and sell to be consumed off-site. The can, called a crowler, is praised for its convenience and ability to keep beer fresh longer than traditional to-go packaging does.

The problem, state regulators say, is that the law prohibits retailers who do not have a manufacturing license from operating the filling machine. Last week, the Texas Alcoholic Beverage Commission made its most forceful statement to date, sending in agents to seize one of the machines from a bar that failed to cease operations after being ordered to do so.

The Cuvee Coffee Bar in Austin recounted the event on social media, giving it a Twitter hashtag of #crowlergate and setting the stage for another potential legal fight in the ongoing effort to change the alcohol code in Texas.

The friction began in late spring, when regulators heard about the growing popularity of crowlers and began investigating, often undercover. Several bars and restaurants were told to stop crowler sales and seven received letters threatening fines and a suspension of their beer and wine licenses.

They were given 30 days to remove the machine, which retails for $3,600.

In announcing the seizure at Cuvee, the TABC acknowledged the likelihood of a legal challenge.

“We know this issue is important to craft beer retailers and their customers, and we support all citizens’ right to petition the Commission, the Legislature or the courts if they feel a provision in the Alcoholic Beverage Code is unfair,” assistant chief for audit and investigations Dexter K. Jones said in a statement. “However, we do not support the continued violation of the law just because a retailer disagrees with it. Cuvee Coffee ignored our repeated warnings and discussions, and that conduct resulted in TABC seizing the illegal equipment and subjecting its permit to a civil penalty. Other retailers who engage in illegal canning risk similar consequences.”

Local bar owners say crowlers have several advantages over growlers, the glass or metal containers more commonly used for to-go sales. Sealed cans keep beer fresher by insulating it from oxygen and any sunlight, they say, and they are convenient because customers don’t have to plan ahead and bring a growler with them when they go out.

Ben Fullelove, owner of the Petrol Station craft beer bar in the Garden Oaks/Oak Forest area, and Todd Hayden, owner of Hop Scholar Ale House in Spring, said they also found takeaway beers encouraged people to avoid having one too many before they get in their car.

Both pub owners got warning letters from the TABC, which draws a distinction between hand-capped growlers and the machine-sealed crowlers.

Hayden said he believes state officials are misapplying a manufacturing law to a retail business, but he plans to adhere to the current legal interpretation.

Sept. 28 was the deadline for wrapping up crowler sales at Petrol Station. Fullelove said TABC representatives were out the next day to ensure the machine was gone.

“They’re being nit-picky about laws for no good reason,” he said. “I would understand if there’s public safety involved or unfair business practices.”

Fullelove said he plans to use the machine at his brewpub, Brash Brewing, once it opens to the public because that business is licensed for manufacturing.

The machines are sold by Colorado-based Oskar Blues Brewery. An ardent advocate of canned craft beers, Oskar Blues began selling crowler machines to retailers almost two years ago after retrofitting one to work with cans from its manufacturer, Ball Corp. The brewery also sells cans, lids and labels with graphics on them.

Spokesman Chad Melis said the company sold 207 machines, 815,000 32-ounce cans and nearly 1 million lids in 2015, through July. He said legal issues arose in only two other states: Minnesota, which declared all such containers be made of glass, and Virginia, where retailers would have to fill a small number of cans before opening and have them for sale. Melis said Oskar Blues has offered refunds to Texas bars that purchased the machines.