The University of Virginia chose today - the day of the 103d Kentucky Derby - to announce publication of a book claiming that the mint julep, the derby's official drink, actually was concocted in Virginia.

"Kentuckians have even been trying to make up for not being born Virginians," wrote Georgia historian Richard Barksdale Harwell in his book, "The Mint Julep."

"They have seized on their special claim to bourben whiskey as giving them the right also to arrogate the mint julep to themselves," according to his 54-page paperback.

"Clearly, the mint julep originated in the northern Virginia tidewater, spread soon to Maryland, and eventually all along the seaboard and even to transmontane Kentucky," Harwell wrote.

Officials in Kentucky, where thousands of weak, mass-produced juleps will be consumed today at Churchill Downs out of special souvenir glasses listing past derby winners, could not be reached for comment. They were reported to be drinking honest juleps at private parties all over Louisville.

Harwell's book says the first mention of a julep came in an 1803 commentary on the United States by an Englishman, John Davis.

Davis defined it as "a dram of spirituous liquor that has mint in it, taken by Virginians of a morning."

In 1837, another English traveler, Capt. Frederick Marryat, wrote, "They say you may always know the grave of a Virginian as, from the quantity of juleps he has drunk, mint invariably springs up where he has been buried."

The jurep, Harwell says, "is part ceremony, tradition and regional nostalgia; part flavor, taste and aroma; and only by definition liquor, simple syrup, mint and ice.

"It is all delight. It is nectar to the Virginian, mother's milk to the Kentuckian, and ambroisa to Southerners anywhere."

Harwell includes a dozen different recipes in his book but fails to resolve the deep controversy over whether the mint should be crushed in the glass. Serious arguments and perhaps duels have developed over the correct way to make a julep, but all authorities agree that the machine-made assembly-line served derby drink does not deserve the name.

Walker Cowan, director of the University Press, readily admitted that Derby Day was chosen intentionally as the announcement date for the book.

Cowan said that a close friend in Savannah, Ga., had published a 200-copy edition of the slim book in 1975 for his friends. Cowan was given a copy, was charmed by it and decided it was suitable for publication by the university.

He cited the report of British war correspondent Sir William Howard Russell from Washington, D.C., in July, 1862, as a favorite account, Wrote Sir William:

"So ill today from heat, bad smells in the house and fatigue that I sent for Dr. Miller, a great fine Virginia practicioner who ordered me powders to be taken in mint juleps.

"Now mint juleps are made of whiskey, sugar, ice, very little water and sprigs of fresh mint . . . 'A powder every two hours, with a mint julep. Why, that's six a day, doctor, won't that be rather intoxicating?'

"'Well, sir, that depends on the constitution. You'll find they will do you no harm, even if the worst takes place.'

"Day after day 'til the month was over and August had come I passed in a state of powder and julep which the Virginia doctor declared saved my life," wrote Sir William.