Since my usual milieu involves helping people find the cheapest drinks possible, I was thrilled to cover a more refined tasting of California natural wine growers, an event that was part of this week's San Francisco Natural Wine Week. Held at Arlequin Wine Merchant in Hayes Valley, the tasting featured five vintners committed to the art and science of growing, fermenting, and bottling wine the natural way.

Ascertaining the definition of "natural" wine can be tricky; most people assume that, like organic food, the name is primarily based on the way grapes are grown and the use of pesticides. Natural winemakers, however, see the growing process as only the beginning, and are just as concerned with what happens once the grapes are picked. Their primary focus is on two winemaking components: yeast and sulfites. In modern winemaking, handpicked, pre-cultured strains of yeast are usually added to the grapes during fermentation; the results are more reliable, but can be same-y and lacking in that ineffable quality the French call terroir. Natural winemakers use the yeast currently in their fields, tanks, and occasionally even the air, in the hope of creating more unique wines that express a sense of place.

Sulfites, specifically sulfur dioxide, are frequently added during the fermentation process with the goal of protecting the grapes and preventing any strange or "off" flavors. While this is an old technique, dating back hundreds of years, increasing amounts of the compounds are also, in the winemakers' opinion, diluting the character of individual wines. While some amount of sulfur dioxide is naturally present in the fermentation process, these winemakers pride themselves on using little to no outside SO2, relying instead on constant monitoring. There are tons of other tenets some winemakers have enacted, from the type of barrels used to the way the wine is bottled, but these two factors form the central rallying point. As Ian Becker, Arlequin's lead wine buyer, described the standard winemaking process: "It's like if you grew organic tomatoes, and then spritzed them with pesticides to make them look good on the shelf." The philosophy is simple: if you're going to go local, natural, and green, why go halfway?

Mission statements aside, however, how do these wines taste? Based on what I sampled, the answer is plain: really good. A bright, lightly fizzy 2007 "Cassia" grenache from Broc Cellars ($25) lit up the tongue with the flavor of crushed berries, while the same maker's Broadside Paso Robles Cabernet Sauvignon ($19) was mellow and easy-drinking. Many of the wines from Lioco, including the lightly sweet 2008 Sonoma County chardonnay ($20) and the rich 2007 "Klindt" pinot noir ($45), had a funky yet pleasant nose that was reminiscent of really good goat cheese. Another fun experience was trying identical grapes raised in different places: Clos Saron's "Home" pinot noir ($45) had a clean, mineral flavor, while its cousin, the "Texas Hill" pinot ($40), was smoky, rich, and lingered on the tongue.

Natural winemaking can be an expensive endeavor-- taking away all those industrial safeguards increases the risk that a whole batch can spoil or develop an odd flavor-- so it was also refreshing to see that every wine at this tasting was under $45, with five selections below $20. In the overall world of wine, especially the U.S., natural winemaking remains uncommon, but tasters and growers alike expressed hope that the movement will continue to blossom. Even in its current small state, the "natural" label is a great signifier for interesting, unique, and flavorful wines.

The wines mentioned above are available at Arlequin Wine Merchant (384B Hayes St., Hayes Valley). For more information on San Francisco Natural Wine Week, visit their website.