Starbucks Corp , which sells the coffee that helps many Americans get wound up for their day, is now offering some a way to wind down.

The company plans to begin selling beer and wine in a small number of cafes in Atlanta and Southern California by the end of this year as it explores an expansion beyond morning coffee and afternoon pick-me-ups.

Starbucks is planning to add the alcoholic drinks and food such as savory snacks, cheese plates and hot flatbreads to menus in four to six outlets in each market.

The world's biggest coffee chain started selling such items at a neighborhood Seattle cafe in October 2010. Five stores in the Seattle area and one in Portland, Oregon, now offer the extended menu.

The company, which already has announced plans to bring the new items to five to seven Chicago-area cafes by the end of 2012, also is testing wine and beer sales in Spain.

As our customers transition from work to home, many are looking for a warm and inviting place to unwind and connect with the people they care about, Clarice Turner, Starbucks' senior vice president of U.S. operations, said in a news release.

The company does not expect to sell alcohol in all of its nearly 11,000 U.S. cafes.

Quick-service restaurant chains in the United States are adding morning and late-night menus, extending food and drink options and lengthening operating hours in an effort to boost sales.

Starbucks, Burger King and Sonic Corp are among the chains experimenting with alcohol sales in the United States.

Seattle-based Starbucks, which is coming off a successful restructuring, recently has reported some of the industry's strongest sales trends. Its shares fell about 1.6 percent to $47.38 in afternoon trading on Monday, but are up more than 40 percent from a year ago.

The company, which already offers breakfast and lunch, hopes its latest effort will ring up more late afternoon and evening sales.

Such efforts have their critics.

California-based industry watchdog Alcohol Justice has criticized alcohol sales by Starbucks and fast-food chain Burger King, which offers beer at its new Whopper Bar restaurants.

Sarah Mart, the group's director of research, said many U.S. neighborhoods already have plenty of bars, restaurants and stores that sell alcohol.

The more places that open, the more risk there is of alcohol-related harm such as underage drinking, Mart said.

(Reporting by Lisa Baertlein in Los Angeles; Editing by Lisa Von Ahn and Tim Dobbyn)