[stained barrel]

No filter, no cry

There comes a moment in every young wine writer’s life when they dabble at becoming Robert M. Parker, Jr. When knowledge of wines crosses the Rubicon into a vastly more satisfying (and self-satisfied) knowledge of wine, and the urge to proclaim their understanding suddenly becomes overwhelming.

With fair frequency, the very next moment in every young wine writer’s life is someone with vastly more knowledge explaining that they’re wrong.

I’m pretty sure my own era of ranting from a illusory mountaintops happened around the turn of the millennium; I was convinced I was on my way to being a Master of Wine (I wasn’t), I had done the work of tasting and study (but not nearly enough), I knew stuff (only some), and I had regular outlets through which to bestow my undoubtedly brilliant and precious insights on an eager audience.

Reading my work from those days is now a matter of silencing endless groans of embarrassment, and there are more than a few things I wish I could permanently expunge. But what I really wish is that I’d preserved the admonishments and corrections from (mostly) patient correspondents. I could make copies and forward a parcel to each new writer as they enter their own personal Enlightenment, accelerating the arrival of their own personal Disillusionment.

Most eventually pass through this boastful phase and move on to a truly satisfying era in which excitement and energy are drawn from unknowns, from yet-unsolved mysteries, from new horizons. An unfortunate few remain Parkeresque, driving anchors deep into their epistemological turf, cementing them into permanence, and screaming bloody murder at heathens and apostates who dare question their god-like authority.

And so it was that I prepared for the worst as the following pull quote scrolled past my not-quite-awakened eyes this morning:

Enough about sulfur already. More wines are ruined by filtration.

“Uh-oh,” I fretted. For the author is still young, and occasionally inclined to shout.

It needs to be said, for the record, that Aaron Ayscough — the author of the piece in question — is a friend. An argumentative friend with whom I conduct occasional and unfortunate screaming matches in otherwise sedate Parisian cocktail bars. (Thankfully, they let us back in.) Still, disagreements aren’t exactly uncommon between us, and mostly they remain abandoned and unresolved. Attrition leads to scorched earth, and unfortunately we’re both exceedingly stubborn people.

These days, Aaron is splitting his time between “real life” and Beaujolais, doing the on-the-ground research for a book on the latter. As such, it’s inevitable that the growing burden of the experiential seeks a foundation upon which to rest, and this is — aside from an occasional paragraph here and there — Aaron’s most thunderously definitive and anticipatory broadside. I expect it will recur in his book, to which I look forward.

Praise first: if Aaron has a signature flaw as a writer, it’s spending so much time culturally situating his reportage (and then positioning himself as an external, above-the-fray observer of his opinions) that he eventually fails to make an argument at all, or at least to take ownership of his thesis. Sometimes, the entire edifice dissolves under the weight of excessive equivocation. Since I’m entirely capable of suffering the same urge, I’m sympathetic.

He does not do that here. He explains the issue, he takes a firm stand, and he backs it up with both his own experiences and those of winemakers. One doesn’t need to have their own knowledge, nor a predisposition towards either side, to read his missive, understand what filtration is, why it should or shouldn’t be used, and to exit the essay in full knowledge of Aaron’s opinion. As statements go, that’s a thorough and robust one, and I don’t doubt the traffic will follow.

Here’s more praise: I totally agree with him that making sulfur the idée fixe of natural wine is lunacy. Where we probably part ways is that I think the obsession with sulfur is, very nearly in its entirety, a nutty one. Yes, it would be preferable if JJ Prüm and others used less. I think pretty much everyone else, unless compelled by vinous religion (in which case praise be to Vulcan), should go ahead and use a little, and that we should all stop talking about like the Most Important Thing in the World. Unless there’s an actual (and rare) allergy involved, it’s just not that big of a deal. As Aaron correctly points out, there are quite a few potential interventions from vine to bottle that are vastly more deformative, and thus more important.

Having praised, I now arrive at a contradiction. This one far less shouty and gin-fueled than our last:

To be fair, blind tastings are tough. Beaujolais, and gamay overall, begins with a reputation for lightness, which might cause some tasters to presume a filtered wine is naturally light. But one of the more noble challenges of wine appreciation lies in preserving one’s palate from habituation to technological shortcuts in vinification. This includes filtration, no less than sulfur overdoses or lab-cultured yeasts. In each instance, the potential quality of a wine is being sacrificed for the sake of a regularity more amenable to industrial distribution norms. The fact is that Kermit [Lynch]’s 1980’s crusade against wine filtration is still relevant today – particularly with regards to gamay, which seems to lose more from filtration than many other red varieties. Filtration of gamay is stylistically determinative: once you become attuned to it in a wine, it’s as obvious as the difference between the burnish of real wood and the sheen of a plastic substitute.

It’s clear that Aaron believes this. But he’s probably wrong.

It’s not just blind tasting that’s hard. Tasting is hard. It goes well beyond skill. One must first manage our most complex biological instrument: the mind, ever prone to conflating what it knows and what it believes, what it senses and what it feels, the neurotransmitters that are true and the electrical impulses of environment, moment, and context. One must then link with another pair of unreliable instruments — the nose and the palate — that suffer from chemical vicissitudes unique to each individual and the body’s ever-changing rhythms.

It’s a wonder we’re able have any sort of conversation about tasting at all, and the relative poverty of our organoleptic communication — tasting notes are such an insufficient tool, though we’ve yet to discover better — is certainly explained by these variables. But I think we forget just how much of that insufficiency is entirely internal. Much of what we know is based on foundations far more ephemeral than we’re willing to admit.

There was a time I was certain that carbonic maceration could be definitely and consistently identified. That spiky, berried freshness; it’s so obvious, isn’t it? Then a winemaker took me aside and walked me through some chemistry, demonstrating that what I thought was one thing could actually be a fair number of other things. Another challenged me by filling some glasses and putting my confidence to the test. That neither the science nor my alleged skill supported my boast never quite served to dent my desire for surety, and somewhere in a dark corner of my ego I still believe that I can identify carbonically macerated wines. But the actual fact of the matter is: sometimes I can, and sometimes I can’t. The skill isn’t reliable. And so, to this day, if “carbonic” makes a written note it comes with a question mark, unless I can verify one way or another. Because while I do still crave surety, the fact is I’m not sure. The difference between then and now is that I’m satisfied with that state of affairs.

And so we come to filtration.

Adventures on the Wine Route — importer Kermit Lynch’s semi-commercial memoir and the public urtext for his anti-filtration pedagogy — remains, to this very late day, my absolute favorite wine book. It formed a lot of my early wine philosophy, and the more I tasted and learned the more I came to sympathize with its ethos. It feels right, and true. Even if it’s not, I’d wish for it to be.

Armed with that philosophy, I remember the first time I knew without question that a wine had been stripped by filtration. At Navarro, I tasted a beautiful, aromatic, texturally exciting chenin blanc from barrel. Later, from bottle, I found a wan, correct wine that was a pale imitation of what I’d tasted. “Filtered,” I assured myself. (And in fact it was.)

But is that what I actually tasted? A barrel sample amidst the relaxed beauty of the Anderson Valley, during a convivial visit to a winery I’d long enjoyed, versus a clinical assessment at my office desk, searching for minutiae and words to express them? Or did I just taste the difference between the contexts and the moments, interpreted by the two different tasters I was at each time?

Can one taste the aftereffects of filtration? Kermit Lynch believes the answer is yes. So does Aaron. (So does Parker.) So do very, very many winemakers and tasters.

To confirm this belief, one necessarily begins with the core issue: a filter must do something organoleptically identifiable to the wine. Does it?

Science says no.

The above-linked presentation, reporting an analysis entitled Evaluating the Effects of Membrane Filtration on Sensory and Chemical Properties of Wine and narrated by David E. Block of the Department of Viticulture & Enology at UC Davis, is uncompromisingly definitive. There are no measurably significant structural or sensorial changes to wine as a result of filtration. What there are, instead, are a very small set of sensorial changes over time from the physical act of filtration — a form of bottle-shock, itself a somewhat controversial notion — that revert to the norm as a fairly short amount of time passes.

In other words, a filtered wine tasted soon after filtration will show certain (limited) effects from the disturbance similar to those shown by a wine roughed up in transit, but with a little patience even those effects recede and become analytically indistinguishable from an unfiltered wine at the same age.

(In the past, I’ve seen studies that measured chemical differences in wines of much greater age and came to a similar conclusion — though, of course, there is bottle-to-bottle variance over longer time frames that must be accounted for — but I’ve failed to locate them while writing this post.)

Aaron quotes a different work (Physical Treatments of Musts and Wines by M. Serrano) that disagrees with Block’s science. Since I don’t have access to this research, I have no way to adjudicate between the two. He also links to an eight year old survey of the then-available research that largely agrees with Block’s conclusion (filtration doesn’t filter anything organoleptically significant), and comes no closer to the alternative view than vague speculations regarding possible vectors.

Vinovation’s Clark Smith, who has made a good living removing alcohol from wine, is nonetheless a vocal filtration nay-sayer, claiming on his Grapecrafter blog and elsewhere that what gets taken out is “soulfulness”

That’s exceptionally weak sauce, especially from Smith. (The speculation does eventually improve, but with little apparent enthusiasm.) Furthermore, the research produced by Block and his team is more recent, and answers some of the lingering theories regarding sensory research in that 2008 survey.


If science is rather strongly suggesting that Aaron (and Lynch, and what must be many, many hundreds of highly skilled winemakers and tasters) are wrong, does that mean that they are?

I think that question’s slightly less answerable, but even less interesting. While sensorial enology is vastly more developed than it was when I started writing about wine, it’s still not complete. Despite all the individual variability, the human sensorial apparatus can be an extraordinarily sensitive instrument (though we’re mere infants compared to many other species), and what current research says is statistically irrelevant doesn’t definitively preclude an alternative explanation. Tasting remains subjective, and who’s really to say that a given taster can’t discern something…especially if they can replicate that discernment? Unlikely isn’t the same as impossible.

But if the palates are wrong, why might they be wrong? Confirmation bias?

Perhaps. One of the biggest traps of wine tasting (one too many naturalistas have eagerly embraced) is the reversal of cause and effect. “I prefer X to Y; X is made this way and Y is made that way; therefore that is why I prefer X to Y.” Maybe, and maybe not. Bemused (or annoyed) winemakers have been known make a blood sport of embarrassing tasters who insist on leaving that error unexamined.

[Adam] Lee presented a 13% and a 15% pinot noir of his to the audience. [Rajat] Parr apparently leaned over to Siduri and said that he’d like to purchase some of the 13% wine. Lee then told Parr that he had, in fact, steamed off the labels, so the wine that Parr had just requested to buy was the one over 15% alcohol.

The issue is different, but the idea’s the same. Without rigorous double-blind tasting, the assertion that one can identify a thing is not the same thing as demonstrating a provable skill.

But what would making Aaron endure such a test prove? If he fails, that he overestimates one particular skill? He’d hardly be the first (see above, re: carbonic maceration). What if we subject Jean Foillard to the same test and he passes it, despite the best science insisting that he can’t? How important is it that so many winemakers are absolutely certain, based on their experience, that filtration is disruptive and deformative?

There are better ways to pass our time than to interrogate every last drop of blood from these subjects. I say this for the same reason that I think the crusade against the plainly anti-scientific aspects of biodynamism is a waste of time. Individual decisions — whether based on cow horns or diatomaceous earth — matter far less than the holistic shepherding of grapes along the path to wine.

I do tend towards the belief that a rigorous examination would contraindicate confidence in one’s ability to taste the aftereffects of filtration. But whether I’m right or wrong about that — and I’d be just as happy to be wrong — the choice to filter is just one of many inflection points along a philosophical continuum that matters a great deal more than whether or not a given taster can identify filtration.

As ever, it’s about intent. It’s about what’s in the heart and mind, more than what’s in the winery.

Filtration is an exercise of control. There are cosmetic reasons to use it (and I agree with Aaron that they’re dubious acquiescences for artisanal producers to make in fear of a low-information market), and there’s a scientifically sensible one (biochemical stability), but the reflexive impulse to push wine through a filter is hard to procedurally differentiate from the impulse to reach for tartaric acid, or bags of sugar, or packaged yeast.

A sensible winemaker might leave herself the option to employ these and other interventions at need, yet choose to avoid all of them if possible. This is, in fact, what’s actually implied by natural wine as a philosophy rather than an arcane and argumentative private club. Another might filter everything as a matter of habit and safety…and the same winemaker is more likely to happily embrace any number of other interventions in an effort to assert dominance over the outcome.

Understanding a winemaker’s urges toward or away from control are far more important to the final result than the specifics of a single intervention. That a wine that is (preferentially, but not necessarily ideologically) unfiltered is more likely to indicate a hands-off approach…one that generates a complex range of qualities that will probably satisfy a preference for such wines. Filtration (or its lack), if a matter of public knowledge, might be a useful canary in the coal mine of potential interventions.

But isn’t that just another form confirmation bias? In a sense. After all, we can’t help but experience the world through our own personal filters.


  • David B

    April 27, 2016

    Thank you for an enjoyable article. There is a discussion going on, at a wine site that will remain unmentioned, about what information people would like added to wine labels. It runs from the predictable (water or acid additions, yeasts, etc.) to the esoteric. Each item on a given label would of course be subject to excruciating debate, and questioned regarding its validity (as was the label of a winery that chose to list the three “ingredients” in its wine) I am all for a little mystery, and less reliance on a label to confirm vinous prejudice.

  • thor iverson

    April 27, 2016

    I read that discussion. It’s like all the previous versions, in which winemakers who wish to defend doing X as harmless play rhetorical games rather than just saying, “X is harmless and we do it. So there.”

    I’d be happy with the list of ingredients, or techniques, or whatever on a web site, but I don’t need it on the bottle unless it’s a true additive (that is, something that wouldn’t already occur in the wine). So you don’t have to list tartaric acid, but you do have to list unfermented muscat must if your label claims it’s chardonnay.

  • David B

    April 27, 2016

    As usual we are aligned.


Leave a Reply