As consumers have shown more interest in what's in their food, some are extending that to wine. What's in that bottle anyway?

At its most basic, wine contains grapes and yeast; the latter converts the sugar in the grapes into alcohol. In most cases, at least some sulfur dioxide is added as a preservative. But there are lots of additives that are permitted, a list that includes everything from water to tartaric acid to brighten up the wine, cultured yeast to ferment the wine (though some winemakers rely solely on the ambient yeast from the grapes and in the winery), coloring agents made from grape concentrate, and chemicals to kill objectionable microbes. Some are benign; some less so.

Ingredient labeling is one solution, but so far, it hasn't been widely embraced by wine producers. There's the ubiquitous "contains sulfites" statement on any wine with added sulfur, but not much else. Ridge Vineyards in Cupertino recently unveiled ingredient labeling on its 2011 wines. On the Ridge website -- www.ridgewine.com -- CEO Paul Draper notes that the winery is listing ingredients to demonstrate that additives and invasive processes are not necessary to make fine wine.

Ridge joins Santa Cruz's Bonny Doon Vineyard, which began including ingredients on its back labels for the 2006 reds and 2007 whites. Winery founder Randall Grahm told me at the time that such labeling would help keep the winery committed to its minimalist approach.

Both wineries also include mentions of fining agents such as egg whites and bentonite, used to clarify wine or reduce astringency, even though virtually no trace of either remains in the finished wines. Bonny Doon and Ridge are to be commended for their forthrightness.

All of which brings me to the proponents of "natural" wines, which are loosely defined as wines produced with as little human intervention as possible. Nothing is added except, possibly, a little sulfur, though some producers avoid even that.

But here's the rub: How much intervention is too much? Temperature control during fermentation, for example? There are no real standards. Natural wine supporters often don't agree among themselves about what's OK. I also don't see a lot of them rushing to adopt ingredient labeling.

The natural-wine crowd turns up its nose at organic or sustainable labels, saying that such terms or practices have been co-opted by "industrial" wineries. And to be fair, government standards allow a lot of additives in organic products. (To clarify the nomenclature, U.S. rules state that wines with added sulfur can't be labeled as "organic." If they are made from certified organic grapes, they may be labeled as "made with organic grapes" or something similar. That also covers imported wines that can be labeled as organic in their countries of origin.)

The European Union last year adopted new standards for "organic," as that term pertains to winemaking, and they are more detailed than U.S. rules. Both place limits on total sulfur dioxide levels for such wines.

Certainly the term "sustainable" doesn't wash with the natural folks. It's true that some sustainability programs rely on self-assessment, which opens them to charges of greenwashing. But the number of third-party certifications is increasing, with programs such as the Lodi Rules, Sustainability in Practice for the Central Coast and Napa Green. These certifications also take into consideration factors such as water and energy conservation, watershed protection and the treatment of workers.

As you might guess, there has been infighting and a considerable backlash against the naturals, many of whom are pretty strident themselves. Critics say there's a not-so-subtle implication that other wines are somehow unnatural. Even wines that are highly processed generally are more natural than, say, soda or sports drinks. Critics also point out that some natural wines can taste funky or downright spoiled, a point even some supporters concede.

I've spent a lot of time reading the back and forth, and it can get vitriolic. So here's an idea: Let's turn down the volume. The idea of intervening as little as possible in the winemaking process, while still making a sound wine, is an appealing one. But natural wine needs a set of standards if it is to have credibility. And "natural" can't be an excuse for spoiled or defective wine.

Let's start with transparency. Ingredient labels, anyone?

Contact Laurie Daniel at ladaniel@earthlink.net.