Starbucks, the company that turned legions of Americans into coffee cravers, on Thursday reported robust gains in sales and earnings during this past holiday quarter.

Sales in stores open at least 13 months increased by 5 percent, somewhat higher than investment analysts had anticipated, and the company also benefited from its acquisition of the stake in Starbucks Japan that it did not own.

Foreign exchange rate movements were the only damper on financial performance that the company noted.

Sales in the quarter, which ended Dec. 28 and was its first quarter for the 2015 fiscal year, rose 13 percent to $4.8 billion, while earnings rose to $983.1 million, from $540.7 million in the same quarter a year earlier, thanks to the Starbucks Japan purchase.