Grandpa’s beer cans are back.

Mass-produced beer such as Coors Light and Budweiser have long been sold in aluminum cans. Now, connoisseurs of craft beer, which traditionally have sided with bottles, are putting more cans in their hands.

“It’s hard to keep up with it. Just in the last six months, it has really exploded,” said Lew Bryson, a craft beer writer and blogger from the Philadelphia area.

A few weeks ago, Sierra Nevada Brewing, a popular California craft brewery, released its Pale Ale and Torpedo India pale ales in cans. Boston beer maker Samuel Adams, long an ardent opponent of selling beers in cans, has indicated it’s working with several manufacturers to possibly develop a canned product.

Pennsylvania brewers, Sly Fox Brewing Co. in Pottstown and Lancaster Brewing Co. in Lancaster, sell beer in cans.

Canned craft beer has been around since 2002, when Colorado’s Oskar Blues Brewery began canning its flagship Dale’s Pale Ale.

In 2009, about 50 small brewers were selling beer in cans. Now, according to craftcans.com, a website dedicated to news about the canned craft beer revolution, the number has grown to about 171 breweries in 43 states, including Washington, D.C.

In the midstate, Troegs Brewing Co. in Derry Twp. and Appalachian Brewing Co. in Harrisburg have yet to jump on the can trend. Both said they wouldn’t rule it out in the future.

Consumers have been quick to embrace the trend. “Like wildfire,” said Bill Moore, brewmaster for Lancaster Brewing, which operates a restaurant in Swatara Twp.

Two years ago, the brewery released its German-style Kolsch ale in a can and followed last year with Rumspringa Golden Bock. Sales have done well, with one Philadelphia wholesaler selling 3,500 cases, Moore said.

“We haven’t had to twist a lot of arms,” he said. “I do take cans and pour them at festivals just to show them beer in a can.”

Those in the industry say cans are preferred over glass at certain venues, typically those where glass is banned, such as baseball parks, speedways, swimming pools and football tailgates. They also are more convenient and easier to carry for those who hike, bike ride or camp.

“The first year we did Kolsch, it was a new product for us, and it was going to be a summer beer, and it was just brainstorming among the players here. ... Craft beer has been kept out of certain venues because of the glass,” Moore said.

“We thought about, and we said, ‘Let’s just take a chance on this and we’ll go with a can,’ ” he added.

Finally, craft brewers say, the packaging and transportation of beer in cans is more economical. Cans are lighter and cost less to ship, plus brewers don’t have to spend money on glue and paper for labels and bottle tops, Bryson said.

Lancaster Brewing’s Moore says it costs the company about $4.50 to $5 less to produce a case of cans versus bottles. The savings is often passed on to the consumer.

Cases of craft beer in cans are priced between about $20 and $26. The price is more than cases of Coors or Miller but less than cases of craft beer in bottles.

Beer drinker Brad Moyer of Lower Paxton Township, who brews beer and blogs under the Fermented Artistry moniker, said that at first he was skeptical of craft beer in cans. Some craft beer fans view cans as inferior. The longtime complaint is the beer tastes metallic.

“I think everybody was a little ‘wait and see.’ Is it going to taste ranky or like soda in cans?” Moyer said. “At first, I think there was this whole snobbery with the cans.”

But he said he was pleasantly surprised and now tracks down craft beer in cans. Moyer said he pours the beer into glasses to drink and views the cans as convenient because they are lightweight and portable.

Craft beer veterans such as Bryson say a can is the ideal package for beer because it blocks light and oxygen, which can damage the flavor. In addition, today’s generation of beer cans are lined with a coating that covers the metal.

Al's of Hampden restaurant in Hampden Township is known for its selection of craft beers sold on draft and by the bottle. It sells several different craft beers in cans.

Sometimes it’s hard to convert people, especially when they don’t want to pay $16 for a four-pack of cans, said owner Al Kominski. But it hasn’t been that difficult to sell.

“Some of the people who have tried the beer in the cans are on board. They are cool with it,” he said.