Brandon Lockridge and his electrician-school classmate stopped into The Vape Bar in San Jose, bellied up to the shiny wooden bar and ordered the usual.

Thunderclouds of vapor soon swirled over the men's heads, then vanished like ghosts. A candy-store scent sweetened the room, courtesy of the featured flavor for October: Witcher's Brew, a combo of peaches-and-cream and butterscotch liquids, noted on a large chalkboard menu in coffeehouse fashion.

This is the world of vaping -- puffing on inhalers sometimes known as electronic cigarettes or vape pens. The devices use small batteries to heat a flavored liquid until it produces a vapor. The liquid may contain varying levels of a nicotine kick, from zero (flavor only) up to 24 milligrams, but no tobacco smoke is produced.

Vaping has become so popular that it's now an official "scene," a subculture with its own lingo: Do you wind your coils in bunny ears or roller coasters? Is variable voltage better, or drip style? How about an RBA (rebuildible atomizer) you can tinker with to adjust the draw, and create more flavor and bigger vapor clouds? Users can subscribe to VPR, "the leading Vape lifestyle magazine," or mingle at a "vape meet."

"It's not just the vapor, it's about the style, being able to have this in your hand," said Peter Edwards, 29, of San Jose, at The Vape Bar, rolling his e-pen with his fingers like a fine cigar. "Once you spark that button on your pen and you get this going, whether it's nicotine or marijuana or nothing in it but flavor, it's cool. You want to be GQ cool."

Lockridge, 27, credits vaping for reduced nicotine intake -- he's down to 6-milligram juices -- but he also just enjoys the bar atmosphere, like hanging out at a neighborhood watering hole.

"I like coming in here, talking to people about the pens," he said, explaining the workings of his device. "This is a single coil. You wrap it, drip the juice on it. I did a lot of research. This one is a second-generation Zmax with a digital display, you can check the battery life. It's fun to tinker with it."

Early e-cig prototypes were introduced in the mid-2000s, but refined devices -- many manufactured by the big tobacco companies -- have grown in popularity worldwide in the past few years. Vaping has been big in Southern California, and the trend recently spread to the Bay Area, where you can find at least a dozen dedicated vape shops in San Francisco alone, not to mention e-cig and vaping supplies available at regular smoke shops across the region. Many users also modify the devices to vape marijuana or other drugs.

Some e-cig brands resemble real cigarettes, glowing on the tip when you inhale. Others look like small mechanical cylinders; users joke they're "Star Wars" light sabers. Some are bejeweled with bling and come in more colors than an iPhone 5C.

In the past few months, e-cigarettes have been making news -- and not necessarily in a good way. While proponents rave that they're a great way to kick the tobacco habit, public health officials and government bodies -- from Bay Area cities to state agencies to the FDA -- are pushing for more research, possible taxation and regulation under existing tobacco laws. Some fear the sweet flavors such as bubble gum and blueberry and the appealing lack of cigarette smoke will lure young people into the nicotine habit, even though it's illegal to sell them to minors. Most shop owners say they ask for ID.

"The act of inhaling anything into the lungs is a concern, particularly if the ingredients are not known," said oncology resource nurse Kitt Kelly at Sutter Delta Medical Center. He added that the medical community is reluctant to play "cultural police" and tell adults what to do.

"But we need to be informed, with actual research," Kelly said. "We need more information, and not in the form of an advertisement or product claim."

At the moment, there is no regulation. Technically, it's legal to vape anywhere in California, even indoors. But even avid vape users say you have to be smart about it.

"There are certain places you want to be discreet," said Alex Westle, 25, of San Leandro, who says he smoked tobacco cigarettes for four years but now vapes "zeros" and works as a clerk at the It Is Vapor 5 shop in Hayward.

"It's legal to vape indoors, but still, you have to have respect," he said. "It's not just you in a room. You have to respect what other people think, and lots of people don't even know what these are. Usually if you explain it, people are pretty cool with it."

They may have to be. The Tobacco Vapor Electronic Cigarette Association estimates that about 4 million Americans now use the battery-powered cigarettes, and they project sales of the devices to reach $1 billion by the end of this year.

Indeed, as tobacco smokers are increasingly shunned and public puffing is restricted, it seems regular cigarettes are becoming passé -- a bygone 20th-century habit. Yet the act of smoking is still seen as cool, and e-cigs give people the oral gratification and nicotine that still provides an addictive buzz.

Ed Bongbonga opened The Vape Bar on South First Street in June, and he has had a steady stream of customers, many of whom find him through Yelp or social media, he said. He used to be a smoker, but vaping helped him quit, and he wants to provide this assistance for others.

"My father lost his life to lung cancer, and I decided it was time for me to quit," he said. "I tried patches, gum, counseling. Nothing worked, and then a friend approached me with this," he added, picking up a vape pen and taking a sweet puff of his special "Guavalicious" vapor blend. "A week later, I was off cigarettes."

Starter kits usually run from $30 to $100. But pens can cost as much as $1,000.

"It's almost a collectibles thing now," Bongbonga said.

His clientele is 60 to 70 percent male in the 18-to-30 age range, with "a lot of minorities," and for some reason a lot of nurses and firefighters, he added.

Lockridge vapes "for dating reasons, too," he said. "A lot of women don't want to date a smoker, don't want to kiss an ashtray."

Follow Angela Hill at Twitter.com/giveemhill.