Fresh beer fans in California may find it easier to buy their favorite brews by the jug if the governor signs a bill clarifying the rules on when and how breweries can refill the popular reusable containers known as "growlers."

The state Legislature passed a bill late last week explicitly lifting a longtime ban on brewers filling growlers that did not originate at their own brewery, opening the way for consumers to bring in their own vessels to be filled from the tap. The California Department of Alcoholic Beverage Control had relaxed those rules earlier this year, but confusion over exactly how breweries should handle outside growlers had led many to hesitate to allow them.

"Growlers are a relatively new phenomenon, and without a doubt the statute we have in California was not written with them in mind," said Tom McCormick, executive director of the 300-member California Craft Brewers Association, which lobbied for the change.

A spokesman for Gov. Jerry Brown declined to say whether the governor intended to sign the bill, but the sponsor, Assembly member Wes Chesbro, D-Arcata, seemed optimistic after introducing the governor to the idea of a growler at a social event earlier this year, pouring him a glass of Russian River Brewing's flagship Pliny the Elder.

"He seemed surprised to get draft beer at a social event where there were no taps," Chesbro said.

Growlers are typically glass or plastic jugs, less commonly metal, that are resealable with a screw top or locking flip cap. They vary in size, but most commonly they are either half-gallon or 2-liter capacities. State laws on growlers vary widely, with some banning them or limiting the sizes and others allowing almost any kind of container to be filled by any establishment selling beer on tap.

The new rules passed by California's Legislature specify that breweries may fill outside growlers only if any outside labeling or logos are completely obscured, replaced by detailed information on the maker and type of beer inside.

The bill mirrors the changes made by the ABC in February but is more specific. Under the current ABC rules, McCormick said, breweries are allowed to obscure the old labels temporarily, simply by slipping a sleeve or paper bag over the outside. The new legislation will make clear the old information needs to be covered more permanently, using tape or opaque shrink wrap, or else eradicated entirely.

But the legislation does not require brewers to fill outside growlers and some have vowed not to do so.

Most prominently, Santa Rosa's Russian River has said it will not fill anything except the distinctive narrow-necked vessels bearing the Russian River logo. Owners Natalie and Vinnie Cilurzo posted a note online explaining their decision earlier this summer, raising concerns about the cleanliness of outside growlers and the possible difficulty of using other shapes and sizes on a filling system designed for their custom model.

They also argued that a logo-bearing growler is just as much part of their brand identity as the label on a bottle.

"We work hard to make the best beer possible and are proud to put our name on it," they wrote. "Nothing against other breweries' growlers, but we want our beer going home with you in our branded growler!"

Lagunitas owner Tony Magee echoed those concerns, saying he "would prefer not to" fill outside growlers, though he has yet to decide for sure. Currently, the brewery allows customers to exchange used Lagunitas growlers for fresh ones to ensure that beer goes out the door in a properly cleaned and sanitized jug.

Bear Republic brewmaster Richard Norgrove Jr. said his brewpub would likely allow outside growlers, but it would probably have to add some kind of sanitizing station for them and the beer would come with a warning that the brewery could not vouch for the integrity of beer sold in anything but an official Bear Republic growler.

A poorly cleaned and sanitized jug can allow for bacterial contamination of the beer. Nothing that grows in beer is dangerous to humans, brewers say, but it can cause the beer to taste bad, a problem brewers fear might reflect badly on their products.

Other brewers were not as concerned. Mendocino Brewing and Third Street Aleworks, for example, said they would fill outside growlers, as did newly-established Carneros Brewing east of Sonoma, despite having invested in a stock of growlers painted with the elaborate brewery logo featuring five rams.

"We have a beautiful growler they can buy on-site," brewmaster Jesus Ceja said, "but if they want to bring a growler from another brewery, that's A-OK."