There are a number of unusual things about Silver Oak Cellars. Firstly they make only Cabernet Sauvignon, strange here given that even if the Cab’s the main event there’s usually plenty of serious tinkering with other varietals. Secondly the wines are aged exclusively in American oak. Also they produce two versions, one Cabernet from Napa Valley fruit and the other from fruit grown in the Alexander Valley. It was three vintages of the Napa Valley blend – 2008, 2005 and 2002 – that were shown by Vivien Gay at the Napa Valley Vintners’ tasting this summer. In addition identical vintages of single vineyard Merlot from Twomey Cellars were also shown, Silver Oak’s distinctly francophone sister property.