Bourbon's reign as the preferred drink of Virginians will be challenged next month when A. Smith Bowman Distillery of Sunset Hills, Va., begins the state's first commercial vodka bottling effort.

For the past 48 years, Bowman's distillery has been in the bourbon business. But on Feb. 1 it will begin an attempt to capitalize on what company President E. DeLong Bowman calls "a growing market" for low-cost vodka in Virginia, with initial production set at 150,000 cases a year.

Although fiscal 1982 profits were flat for Bowman's, vice president for production Jay Adams said sales were up 12 percent for the first quarter of the company's fiscal year that began Oct. 1 and expected that they would improve even more after introduction of the vodka line.

Bowman's currently brings in between $10 million and $12 million a year from sales of its Virginia Gentleman Bourbon. Adams said the company hopes to match that performance with the vodka by undercutting the price of all competitors.

Adams said Bowman's vodka, which the company will purchase from two distilleries in the Midwest, will sell for $3.90 for 750 milliliters and that a survey indicated the price matches that of the least expensive vodka at surburban Washington stores managed by the Virginia Alchoholic Beverages Control Board.