Yeast Inoculation – Threat or Menace?

The panel discussion at the Portland Indie Wine Festival panel discussion on Natural Wine in the Age of Technology held fascinating lessons for me in the disconnect between consumers and winemakers. Our hope was to arrive at a definition, perhaps even a Certification Mark, for Natural Wine. If a list of winemaking practices is commercially practical (unlike Organic Certification), many winery players will choose to participate. I argue in Natural Wine: Choosing Your Priorities that several consumer groups with different agendas are rallying under the Natural Wine flag. Careful thought is needed to determine the mountains everybody wants to die on.

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.



Bruce Gutlove:

"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."

Oh, the horrors! Wild ferments sound like a veritable witches' brew!

The matter is a complex one, no doubt. But there are a number of producers who produce pure, fruit-filled, complex wines without the use of WADY. Maybe it takes a little more effort. Maybe the percentages are slightly less attractive than for those who add yeasts. Maybe they "cheat" a bit, using old cooperage and unsterilized equipment to help get things started. Maybe it requires a bit of a re-think as to goals, definitions, priorities, etc.
But it can be done.

And if they can do it, then California producers surely can as well.
If they want to, that is...

To Bruce:
Clean wines are often made without inoculation; not as surely as with it, but in certain styles the extra flavors can be positive. As a winemaker, I feel the style choice is part of my perogative. I see no right answer, no moral good that is served either way. As far as I can tell, proponents of "feral ferments" are concerned about artificial flavors from packaged yeast. Not only is this concern overstated, but uninoculated wines are in my experience more prone to such flavors than commercial yeast fermentations.


Jerry D. Murray:


The fact that you 'see no right answer, no moral good either way' separates you from those who villify the use of cultured yeast. I suspect that many of the advocates have somehow convinced themselves that these yeast have some how been engineered or genetically altered. Most of the commercial yeast used today are simply selections of existing 'wild' yeasts that have been propagated and cultured. If the yeasts indigenous to a given winery or vineyard are an important aspect of 'terrior,' are those that villify commercial yeasts also willing to villify wine produced from yeasts, though wild, that are not indigenous to a given winery or vineyard?
For the record I employee 'native' yeast ferments but find wild malolactic ferments just too damn risky. I don't believe that a wine marred by Brett or some of the spoilage bacteria accomplishes my goals of expressing the characters of my vineyard. In fact I don't think such wines express anything except the microbial cocktail that has left its signature on them. They are not just stripped of their sense of place but of their varietal character as well.

Bruce Gutlove:


This is, as you say, a stylistic choice.
"Right" or "wrong" will depend upon your stylistic preferences, goals, and priorities. And what is right for one may not be right for another.
For me, philosophically I'd like to see additions kept to a bare minimum; so, if one can make good wine without adding yeasts I'd prefer to have it that way. Too, clean fruit characters in a finished wine aren't really a top priority for me... I do like to see good fruit character, but I am happy if it is balanced with other, less fruity components.
So, in all I'd prefer to see indigneous yeast ferments more common in the New World as well.

I'm not sure how over-stated the case is re: artificial flavors from yeasts. Fermentation esters are pretty ephemeral, to be sure. But wine-searcher is listing over 950 California wines from the 2007 vintage as already available for purchase. Stainless steel whites and roses fermented at extremely cool temps, stored cold after fermentation, treated to a modicum of SO2, and cleaned up and bottled quickly using a careful application of relevant technologies... many of those '07s are still going to be estery now.
Beyond that there are other factors at work. Some yeasts yield aromatic compounds that are much more stable. An obvious example would be the higher yields of thiol-based aromatics from yeasts like Zymaflore X5 and VL3. These yeasts can substantially alter the aroma profile of a given wine. If the wine in question is SauvBlanc then maybe something like VL3 would merely serve to intensify what was already there to begin with. But using such yeast strains on things like CH or Petit Manseng or Colombard really produces something quite atypical.

Anyway, I'm not about to crucify anyone if they're inoculating. But I'd like to see more interest in learning how to do without.


mark bunter:

"Organic" as an adjective and marketing shibboleth has some emotional social baggage, but as a legally defined agricultural technique it is cut and dried. "Natural" is a word so fraught with ethical peril and value implications that you will all be sucked into the black vortex of its cavernous maw, leaving only your echoing screams of terror, and a few lawsuits, in your place.
I, too, think wine purchasers should have the option of knowingly buying wines made simply. Randall Graham has shown the way. Your winemaking philosophy should be an element of your brand identity. There's no need for a certifying body to "prove" you are simpler than the next winemaker.
Speaking personally, I'm secure in the knowledge that I'm simpler than most. Put it on your back label. There's room. Thanks to global warming, we no longer need world maps showing we have exactly the same latitude as Dublin, Ireland, or wherever. Thanks to KJ, we don't bother with annoying technical data like R.S. So, just nudge the "Government Warning" paragraph over a bit and tell the world what you did or didn't put in the wine. Just like every food label has to. Wow. What a revolutionary concept. "Ingredients: Grapes, yeast, sulfur dioxide" PERIOD. (Hint-don't mention the MOG!)