By Martinne Geller

NEW YORK (Reuters) - Molson Coors Brewing Co (TAP.N: Quote, Profile, Research) posted a better-than-expected quarterly profit on Tuesday as volume gains and price increases offset rising commodity costs, sending its shares up nearly 8 percent to a six-month high.

The maker of Molson Canadian and Coors Light beer said net income in the first quarter ended March 30 jumped to $37.1 million, or 20 cents per share, from $4.4 million, or 3 cents per share, a year earlier.

Excluding special charges of $7.3 million and one-time debt extinguishment costs of $12.4 million, the company earned 32 cents per share. On that basis, analysts, on average, were expecting 26 cents per share, according to Reuters Estimates.

Goldman Sachs analyst Judy Hong said results were strong across the board, with impressive sales growth, solid pricing and cost savings ahead of expectations.

"We expect the solid underlying volume and pricing performance to dispel concerns about the competitive outlook," Hong said, adding that she expects momentum in the company's portfolio, which includes Coors Banquet, Keystone and Blue Moon, to continue despite improved sales trends for rival Anheuser-Busch Cos Inc (BUD.N: Quote, Profile, Research).

The company said its underlying tax rate was 2 percent in the latest quarter, down from 21 percent a year ago.

The weakness of the U.S. dollar versus other currencies added $4 million to Molson's profit.

OUTPERFORMING THE MARKET