A warning to Internet-surfing coffee shop patrons: Make sure your computer and phone are charged ahead of time.

Customers are finding that power comes at a premium — or not at all — in some shops that have disabled or removed electrical outlets.

Other coffee purveyors are limiting, or just plain eliminating, wireless Internet in an effort to get customers unplugged and keep tables turning over.

Crema Coffee House at 29th and Larimer streets recently covered its sole power outlet in the customer seating area.

Noah Price, co-owner of the bustling shop, said he was growing concerned about customers bringing in extension cords and snaking them across the floor to keep their laptops and tablets charged.

“We feel like we shouldn’t be responsible for people’s equipment,” he said.

Price said the decision to go power-free was based on safety and aesthetics, not on concerns of people tying up a table all day.

“We want turnover, too, but we’re not going to be jerks about it,” he said. “People can spend as long as they want here.”

The “laptop hobo” phenomenon — patrons buying one coffee and spending ensuing hours browsing the Web — is a growing issue with food and beverage operations.

Wooden Spoon, a Highland neighborhood coffee shop on West 32nd Avenue, decided last year to disable its Wi-Fi and ban laptops and tablets.

“It got to the point where we had customers watching YouTube videos and blasting them at full volume,” said co-owner Jason Burgett. “We’re a small shop with only 16 seats. We prefer that our customers have the opportunity for social interaction.”

The nearby Gallop Cafe also disabled Internet service and prohibits computer use — even for customers using their own networks — during busy periods.

Panera Bread imposes a 30-minute limit on Wi-Fi use from 11:30 a.m. to 1:30 p.m. Aside from that two-hour window, no restrictions exist.

“This time limit helps us service more customers at our peak business hours and frees up more tables,” said Panera spokeswoman Missy Robinson. She said the chain has received more complaints about table availability than it has over the Internet limit policy.

Internet forums are rife with reports that some Starbucks outlets, notably in New York City, have covered power outlets to prevent all-day lingering.

A Starbucks spokeswoman said there is no corporate policy on providing power to computers, with individual shops free to make their own decisions. She said she is not aware of any Denver-area stores disabling outlets.

Crema Coffee’s Price said he views it as a nonissue because “hanging out all day is more of a ’90s coffee shop style.”

Crema customer Cory Martin agreed, saying she’s not concerned about the ability to plug in her laptop.

“I’m usually not going to spend all day with my computer at a coffee shop,” she said. “I like coming here because the food is good and the people are so interesting.”

Steve Raabe: 303-954-1948, sraabe@denverpost.com or twitter.com/steveraabedp