An employee of Farmer Bros. for his entire adult life, Farmer took over as chief executive in March 2003 from his father, Roy F. Farmer. Last June, Roy E. Farmer also became the publicly held company’s third board chairman in 93 years, succeeding his father, who died in March 2004.

Company spokesman Jim Lucas declined to comment on the cause of the younger Farmer’s death.

In a special meeting held Jan. 9, Farmer Bros.’ board elected Guenter Berger as interim chief executive. Berger, 67, is a 44-year veteran of Farmer Bros. He has served as vice president of production since 1990, with responsibility for inventory, production, coffee roasting and distribution operations.

“Guenter knows every aspect of our operations better than anyone, has earned loyalty and support from employees and suppliers alike, and has shown himself to be a capable and effective leader during his 24 years as our head of production,” said director John Merrell in a statement.

The death of Roy E. Farmer throws the future of the company, which was founded by the Farmer family in 1912, into doubt. Roy E. Farmer and his father maintained a tight grip over the insular company through control of personal, family and employee shareholdings.

Their stewardship has been challenged in recent years by a large contingent of institutional shareholders, at times including extended family members. Farmer Bros. has been perceived as stagnant during a period when the coffee-drinking market has expanded dramatically, led by Starbucks Corp.

Some shareholders have called for a management shakeup or even the sale of the company, and already on Monday, it appeared that some Wall Street traders expected some kind of shakeup in the wake of Farmer’s death. In mid-afternoon trading on Monday, Farmer Bros. shares were up $1.95, or 8.7 percent, to $24.44.