Farmer Brothers Co. saw its net loss grow 6 percent in its fiscal fourth quarter as the coffee roaster continued to battle higher raw materials costs and a decrease in the number of business customers it serves.

The Torrance company reported a fiscal fourth quarter net loss of $22.3 million (-$1.47 a share) for the quarter ended June 30, compared with a loss of $21 million (-$1.40) in the same period a year earlier. Its operational loss increased 41 percent to $31.4 million.

Net sales rose 12 percent to $119 million. The company attributed the increase to its passing on to customers the higher prices it was paying for coffee, cappuccino, cocoa and spice products. The sales growth was offset by a decrease in the number of customers who purchased its products.

Farmer Brothers’ financials have suffered as coffee bean prices have doubled over the last 18 months and cost-conscious businesses cut back on the beverage service they offer employees. The company responded by trimming operating expenses, laying off workers and developing a more sophisticated method to hedge its coffee costs.

“The rapidly escalating coffee prices of the recent past had a significant impact on our cost of goods sold for fiscal 2011,” interim Co-Chief Executive and Chief Financial Officer Jeffrey Wahba said in a statement.

Shares were down 19 cents, or 4 percent, to $4.56 in Wednesday midday trading on the Nasdaq.