What makes a wine organic, sustainable, biodynamic or natural?

The wine world is vast, and can be complex and confusing: There are so many grapes, regions, wineries and vintages.

So it's quite understandable that many consumers appreciate finding a realm that would seem to be precise — and a happy confluence when that domain allows them to be conscientious shoppers.

We're talking about the organic, sustainable, biodynamic and natural categories.

"This particular question is the one that people feel most comfortable asking about," said Daniel Brashi, wine director of South Lyndale Liquors in Minneapolis. "It's often harder to ask other questions about wine."

But consumers find little help from labels or certification. Which is one reason why all consumers should develop relationships with a wine merchant, or three.

Brashi said he's definitely seeing more people asking about this, adding that he and his staff have been slapping plenty of stickers that say organic, biodynamic and sustainable on bottles. He notes, however, "You can't get to all of them."

That kind of effort is commendable, and unfortunately necessary because even the most responsible vintners often eschew certification because of cost, bureaucratic hassle or, well, the reality that sometimes a pest or disease will appear and necessitate the use of chemicals that preclude certain official classifications.

Many winemakers also are not sold on that kind of farming anyway. "Organic farming doesn't produce the best soil nutrition," said Ken Wright, a Wisconsin native whose eponymous winery produces some of Oregon's best wines. "We inject live microbiology because nutrition-based farming, to me, is the ultimate form of farming."

The good news is that more and more wineries, big and small, are going the sustainable route.

"Everybody is moving toward being responsible," Brashi said. That means not only the kind of soil care in which Wright engages but also biodiversity, which might include cover crops hosting animals that kill the "bad" bugs, collecting rainwater for use in the vineyard and/or cellar, plus other practices.

Many wineries have also embraced biodynamics, which goes several steps further in soil care, making teas and using animals to fertilize the vineyard and choosing dates for tasks based on the lunar calendar. Wineries such as Brick House in Oregon, Michel Chapoutier and Joseph Drouhin in France, and Bonny Doon in California have led the way, with others following suit.

There's also the natural wine movement, particularly embraced by younger drinkers as a return to the way wine was made a century ago. These wines are made with ostensibly no intervention in the vineyard or additives in the cellar, although practices may vary, and are particularly embraced for shunning sulfites.

A lot of consumers inquiring about wines are doing so because of their perceptions, or misperceptions, of sulfites, Brashi said, and noted that it's probably sugar causing adverse reactions.

Indeed, studies show that only about 1 percent of Americans are allergic to sulfites (closer to 5 percent for those with asthma). Among the foods with exponentially higher levels of sulfite are dried fruit, canned anything and bacon.

Bottom line: To be smart and conscientious when buying wine, start with asking at the store or restaurant, because the folks there should know.