In a move believed unprecedented in the American wine trade, Bonny Doon Vineyard of Santa Cruz next year will start to list ingredients on the back label of its wines.

Randall Grahm, the winery's owner, is making the move because he wants to make his winemaking more transparent and because he is aware that some consumers are concerned about allergic reactions to elements used to produce wine, says Burke Owens, spokesman for the winery.

Grahm's ingredient label, recently approved by federal authorities, will consist of two parts, one listing ingredients known to be in a wine, such as grapes and sulfur dioxide, the other outlining products used to process wine that may leave behind trace elements, like yeast hulls and bentonite, a fining agent, says Owens. Unlike some wineries, Bonny Doon uses no animal or dairy products in its winemaking, so none will be listed, says Owens.

The first wines with the new labels, under the Ca' del Solo brand, are to be shipped to markets in February. Ingredient labeling will be affixed to all wines released from the 2006 vintage forward.

Grahm is taking action voluntarily, though federal officials are weighing a proposal to require vintners to put on their bottles a warning that major food allergens have been used to help make the wine.