The story appears in a forthcoming and unauthorized biography of the senator by Manuel Roig-Franzia of the Washington Post.

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Mr Franzia, who anticipated the glut, cut production at his own vineyards and then stepped in to buy the excess grapes at a knock-down price.

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Mr Franzia's firm, the Bronco Wine Company, brings California's excess grapes to its plant in Napa Valley from all over the state. (The firm's use of the Napa name on its labels is, as a result, currently the subject of a lawsuit.) Bronco owns an efficient modern plant and has its own distribution network, so it can deliver wine directly to Trader Joe's warehouses, which keeps costs down.

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