A deal to sell Kenwood Vineyards to New York-based Banfi Vintners has unexpectedly fallen apart, leaving the prominent Sonoma Valley winery in the hands of F. Korbel and Bros. owner Gary Heck.

"Although a letter of intent between the two parties was announced in late March, F. Korbel and Bros. will continue to own and operate the winery," Korbel spokeswoman Margie Healy said in a statement issued Monday.

Calls seeking comment from Heck were directed to Healy, who declined to answer questions, citing confidentiality agreements.

Founded in 1970, Kenwood Vineyards became one of the most visible wineries in the Sonoma Valley. Founders John Sheela and his two brothers-in-law, Mike and Marty Lee, converted the old Pagani Brothers jug wine facility off Highway 12 into a modern winery focusing on award-winning varietals, a transformation that mirrored the evolution of the county's premium wine industry in the &‘70s and &‘80s.

Heck acquired a 50 percent stake in the winery in 1996 and bought out the founders three years later. Under Heck's management, Kenwood nearly doubled in size, growing from less than 300,000 cases in 1999 to more than 550,000 cases last year.

In March, Heck said selling Kenwood would allow him to focus on investment and growth opportunities for his sparkling wine and brandy brands, Korbel's core business. The sale to Banfi had been scheduled to close in June.

Representatives of Banfi, which is headquartered in Old Brookville on New York's Long Island, did not immediately respond to requests for comment Monday.

Banfi Vintners is a privately-held family business started in 1919 by John F. Mariani Sr. in Italy. The company's first venture into U.S. wine came in 2010, when it purchased Pacific Rim in Washington.

The Korbel winery, founded by three brothers from what is now the Czech Republic, began operations in 1882 along the Russian River and began shipping its first California champagne in the mid-1890s.