Near the confluence of Mitchell and Mount Diablo Creeks, Joel Clayton planted 28 acres with a variety of grapes, and built a small winery which later became known as the “sherry house” for distilling brandy and sherry. His vineyards thrived, and other settlers followed Clayton’s example because Clayton grapes produced good wines which commanded high prices.
After Joel Clayton died in 1872, his heirs sold the vineyard and sherry house, which encompassed 43 acres, to Paul De Martini. Paul De Martini was born in Genoa, Italy, in 1844. He came to the U.S. in 1861 and moved to Concord, California in 1865. He had a vegetable garden on the Galindo property in Concord. Later he moved to the coal mining community of Nortonville, where he operated a boarding house for two years. He then moved to Clayton, where he bought approximately 44 acres from Joel Clayton, and planted his vineyard.
De Martini Winery (1886)
The winery building is a 50’ x 66’, three story stone and wood structure set into a hillside. The bottom two floors of the 10,000 square foot building are made of two-foot thick limestone from Joshua Marsh’s quarry on the north side of Mt. Diablo, and the third floor hillside level is of wood. The date “1885” is chisled on three inner walls of the winery. Also, the name “P. De Martini” and a silhouette of a man’s face with initials “P.D.M.” next to it are carved on inner walls of the second floor.
The De Martini winery operations were among those that fell to the grape blight and the prohibition era, and the vineyards were replaced with an almond orchard. In November 1940 the De Martini winery was sold to candy manufacturer, George Cardinet Sr. The Cardinets converted the top floor into an apartment for a weekend retreat and storage facility. Purchased by George Forni and his wife in 1962, it was used as a private dwelling until 1979. After that, it sat vacant and was often vandalized. The family had plans to develop the property, and on August 30, 1984 the De Martini Winery/Forni Ranch was placed on the National Register of Historic Places. In 1988, the Clayton City Council voted to spend $900,000.00 to purchase the 104 year old De Martini Winery and eight acres surrounding it.