Along with a sense of humor, wine should have integrity. Bonny Doon has both. On the back label of its 2011 Vin Gris de Cigare, right under the winery’s address — “Santa Cruz, CA, USA, EARTH” — I found this description: “Ingredients: 73% Grenache, 10% Mourvedre, 8% Grenache Blanc, 5% Roussanne, 4% Cinsault grapes, tartaric acid, and sulfur dioxide. In the winemaking process, the following were utilized: Indigenous yeast, yeast nutrients, and bentonite.”

Many wine bottles tell us their grape blends, but this one — unlike most others — tells us what else has been added to create the final product.

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Wine’s dirty little secret is that it isn’t just fermented grape juice. It might include added sugar, tartaric acid, various yeasts and yeast nutrients, color enhancers, gum arabic, gelatin, egg whites, fish bladders (isinglass) and any of a long list of other additives allowed by the federal government but not required to be listed on the wine label. That color and mouth feel you love, even the flavor, might come not from grapes, but from a jar.

As Americans drink more wine, cheap wine has increased in quality, but that improvement has come through chemistry as much as through viticulture. Great wine may be made in the vineyard, but good wine increasingly is made in the laboratory. Today’s winemakers are as likely to wear white lab coats as they are tattered overalls and muddy boots.

Not all of the additives that are used end up in the wine we buy in stores and consume at home; hence the Bonny Doon label’s utilized-in-the-winemaking-process distinction. Bentonite, for example, is essentially clay, used to rid wine of impurities. Egg whites and isinglass perform much the same function; their use might be relevant to consumers who do not want to consume animal products. Why not disclose their use on wine labels?

Randall Grahm — Bonny Doon’s founder, eminence grise and James Beard Award-winning author of “Been Doon So Long” — started listing ingredients and additives with his 2007 vintage. He had recently sold off his mass-market Big House brand of wines and converted all of his vineyards to biodynamic viticulture, an extreme organic style of farming. Listing ingredients on his labels, Grahm says, was a means of emphasizing his new dedication to “noninterventionist” winemaking.

“What customers don’t get is that the style of a wine, especially in the New World, can largely be driven by fairly intrusive stylistic practices: the use of oak chips, enzymes, selected yeasts, etc.,” Grahm wrote in an e-mail. “As a consumer, I really do want to know if the depth of color is something that comes from the grapes nominally represented on the label or from Mega-Purple,” a color additive widely used in red wines. “I do want to know if my wine was treated with DMPC [dimethyl pyrocarbonate] before bottling to kill every last yeast cell inside.”

Grahm did not start a trend. David Page, co-proprietor of Shinn Estate Winery on Long Island, N.Y., started listing ingredients on his labels in 2008, but few others, if any, have followed suit.

“Most people do not know that wine is an agricultural product that can be manipulated almost at will,” Page says. “To some degree, this manipulation has resulted in wines that are better quality than they used to be. There are many more wines on the market today that are drinkable than just 20 or 30 years ago, because flaws can be hidden by chemistry.”

Like Bonny Doon, Shinn practices biodynamic farming, and its customers “appreciate the transparency” of ingredient labeling, Page says.

The Treasury Department’s Alcohol and Tobacco Tax and Trade Bureau, which regulates wine labeling, in 2006 proposed requiring allergens to be listed on the labels. The idea was vociferously opposed by the wine industry, primarily because of cost, says Michael Kaiser, communications director for WineAmerica, a national winery trade association.

Allergen labeling “would require a winery to have several different labels made for each product, because they might vary from vintage to vintage,” Kaiser says. “The need for additional analysis would be a significant cost burden, especially for smaller wineries.”

For Page, the question is simpler. “We think of wine as food, but wine doesn’t have to be labeled as food,” he says. “Why should it be any different than the tomato sauce we buy off the shelf?”

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McIntyre blogs at www.dmwineline. com. Follow him on Twitter: @dmwine.