On some issues there is general agreement in the natural wine community. No Megapurple, no Velcorin. Other requests are too subjective to be readily certifiable, like no excessive oak or excessive hangtime. On other issues, there may be division: barrels vs chips, fining with animal products vs micro-oxygenation. Reverse osmosis has gained some acceptance as a way to support sulfite-free winemaking, but the unnaturalness of “deconstructing” wine was mentioned. (Why bleeding seigné for rosé isn’t also deconstruction was left unclear.)

Anywho, I was really surprised to learn of the strong feeling in the room against yeast inoculation. But I suddenly understood when Alice Feiring dragged out a catalog description from a yeast company. Perusing the extravagant claims of Lallevin or Anchor could certainly lead any consumer to panic. For someone who has never made wine, phrases like“encourages the fresh fruit aromas of orange blossom, pineapple and apricot;” “believed to enhance aromas such as fresh butter, honey, bright floral and pineapple,” or “flavor attributes are often described as ripe fruit, jam, hazelnut, and dried plums on the finish” would certainly be of concern to anyone interested in terroir expression

Here’s the thing, folks. Any experienced winemaker will tell you that yeast companies’ flavor claims are regarded with about as much credibility as a Louisiana campaign promise. First year enology students do fermentation trials on different yeast strains, and yes, there are big initial differences. All yeasts produce esters – banana, pineapple and other fruity aromas, and strains vary. These esters are, however, quite unstable, and a year later, the differences disappear, and are not a factor in most wines in commerce.

In contrast, un-inoculated grape juice is attacked prior to the actually wine yeast fermentation by a whole host of yeasts and bacteria, including Candida, Brettanomyces, Metchnikovia, Pichia, Kloeckera and vinegar bacteria, all of which which leave an indelible and lasting microbial flavor profile which permanently obscures grape expression.

One can argue that this is natural. Certainly it was traditional standard practice until a scant century ago. Fair enough. But the types of wines we drank back then, particularly the whites, have much less commercial viability today. As a result, many winemakers use commercial yeasts in order to protect the purity of grape expression. In addition, vigorous, predictable yeasts make it much less risky for winemakers wishing to work without sulfites or avoid sterile filtration.

Is the indiginous yeast part of terroir? Depends on what you think the "T" word represents. For many winemakers, terroir expression equals presentation of the unique grape flavors which the climate and soil of a place produce.

As with any master baker, a winemaker spends a lifetime honing the skill of selecting the perfect yeast to optimize the extraction of grape characteristics for the specific set of fermentation circumstances being carried out. The main reason winemakers inoculate is cleanness. Second is stability – a vigorous yeast is more likely not to stick. Third is the physical properties, tailored to the intended fermentation regimen: tolerance of hot or cold temperatures, low foaming for barrel fermentations, slower fermentations for more time on the skins, faster or slower breakdown during sur lies ageing. Taking away this prerogative wouldn't result in more unique flavor expression of place, but less -- wines marked more by microbial signatures than grape expression.

It isn’t reasonable for consumers to evaluate these technically complex trade-offs. But they can develop a distaste for the pat answers critics offer up. Suffice it to say that there was no winemaker on our natural wine panel who was willing to eschew yeast inoculation AND sulfites AND sterile filtration.

The ideal will be for all winemakers to be open about their techniques, even the weird-sounding ones, and to explain our rationale the way we did twenty years ago, instead of the endless parade of winemakers claiming nebulously to “do the minimum.” For that to happen, natural wine fans need to practice sympathetic active listening. Talk is cheap for the guy who doesn’t have to live with the consequences himself.