(WineSpectator) - Russian River Partners—managed by Eric Flanagan of Flanagan Vineyards—has bought the 31-acre site, which has a reputation for quality Pinot Noir and Chardonnay.

Russian River Partners, a vineyard investment fund run by Eric Flanagan of Flanagan Vineyards, has purchased the Platt Vineyard, located in the Sonoma Coast wine region near the town of Freestone. The 31-acre vineyard is planted to Pinot Noir, Chardonnay and Riesling and is a source of grapes for several Sonoma wineries, including Ramey, Radio-Coteau, Littorai, Scherrer and Red Car. The price was not disclosed, but the vineyard was part of a larger package of a 500-acre estate and a house that was on the market for $19.5 million.

Joan Platt and the late Lew Platt planted the property in 2003. Lew was a former CEO of Hewlett Packard and Boeing and also served as a top-level executive at Kendall-Jackson before retiring to plant vines in this cool site, just 5 miles from the Pacific Ocean. The vineyard is known for producing fruit with a striking acidity, thanks to its relatively mild climate.

“It was planted to the correct rootstocks and clones, with modern vineyard architecture and detailed planting analysis,” Flanagan told Wine Spectator. “It's near perfect, and we are thrilled to have the opportunity to purchase a site of this caliber.”

For Flanagan, Platt Vineyard will serve as a source for his growing portfolio of Pinot Noir and Chardonnay. Starting with the 2014 vintage, Flanagan has added vineyard-designated wines from Ritchie, Bacigalupi and Sunchase Vineyards.

The purchase of Platt is one of several recent moves by Flanagan's Russian River Partners. Earlier this year, the fund purchased 26 acres in the Petaluma Gap region and, in 2011, he purchased a 56-acre ranch with 29 acres of Pinot Noir and Chardonnay in Russian River Valley from Joe Martin, founder of St. Francis Winery.

Before starting his namesake Bennett Valley winery in 1999, Flanagan, 51, owned the New York–based EMF Financial Products. He ran the winery from his home in Colorado until 2010 when he moved his family to Sonoma County. He has been steadily expanding the business, reaching 5,500 cases in 2014. He grows Bordeaux and Rhône varieties on the estate, but plans to evolve into primarily a Pinot Noir and Chardonnay brand.