Kudos to Eric Asimov and his respondents to his Watch What I Do, Not What I Say blog concerning interventionism in winemaking. My initial response included a reference to "field oxidation" which I promised to expand on here in more depth than I felt appropriate to hog on Eric's site.
“Field-oxidation” refers to the Australian practice of resolving tannin prior to harvest. Fruit left long enough on the vine loses its reductive strength and mean-spiritedness and softens into fruit-forward, user-friendly wine that “makes itself” in the fermenter. My French training under Patrick Ducournau of OenoDev prejudices me away from this style because it deprives the wine of depth, energy, soulfulness and longevity in favor of early drinkability.
This practice is well suited to industrial winemaking, as it leaves little to do at the winery, allowing wines to be made in South Australia’s massive wine factories by minimum wage labor with a limited enological staff able to oversee thousands of tanks without the necessity of daily intervention. It is brilliant in concept, and gave rise to the “flying winemakers” who revolutionized winemaking in southern France in the late ‘80’s. It’s arguably the way to make wine in situations where a “glass ceiling” for quality appreciation is present due to connoisseur prejudice, such as in South Australia, the Languedoc, and California’s San Joaquin Valley.
In Ducournau’s system, we build structure in the winery instead of in the vineyard. We seek refined tannin which acts to integrate aromas just like a finely crafted sauce. This aromatic integration gives soulfulness to the wine, similarly to the way cocoa powder converted to chocolate turns an unpleasant material into something profound. In the cellar we are able to work with much more precision, and the resulting wines have much more life, longevity and interest.
When we hang those same grapes too long, they can't react to oxygen, because the polymerization has already occurred on the vine. We're trying to make a tannin soufflé, but the eggs are already scrambled, so it's impossible to build a structure.
A side benefit of our method is the ability to measure the reductive strength and capacity of a wine. We use a variety of indicators to query the wine – biofeedback if you will – which tell us if the oxygen we’re feeding is being absorbed. We find that wines with excessive hangtime will take up maybe 10% of the oxygen of their properly ripe counterparts harvested from the same vineyard two or three weeks previous. They may taste nice and fruit-friendly in youth, but they will deteriorate much more quickly in the barrel and in the bottle.
I’m to the point where I feel “micro-oxygenation” is so poorly understood, especially by winemakers, that we need a new terminology. Ten years ago, OenoDev was the only company discussing the notion, and we could have a conversation without preconceptions. Their concept was so effective and powerful that it spawned a generation of interlopers, almost entirely wannabe charlatans. Now a dozen competing companies selling dumbed-down machines without consulting support and a score of ignorant academics convening pointless conferences and publishing clueless papers have created a general perception that micro-oxygenation (usually misstated as “micro-oxidation” (choose one) [doesn’t work] [rushes wine to market] [replaces barrels with tanks] [is only for cheap wines] [ suppresses terroir expression / makes wines taste the same].
In what follows, I’ll try to give a general grounding in this brilliant and revolutionary technique, and why I feel Patrick Ducournau is hands down the most important figure in winemaking in the last 100 years. And which of your pundits has mentioned his name?
To begin with, let’s define Micro-oxygenation. Everybody seems to want to use this word for everything, because it's trendy, I guess. I defend the way OenoDev uses the language -- they invented it, so I reckon they get to make the official distinctions.
According to Patrick, there are five ways in which oxygen can be introduced to wine.
1. Hyperoxidation. Saturated (heavy) doses of oxygen to must prior to fermentation. Purpose is to precipitate phenols to minimize browning and astringency in the resulting wine. Also promotes gluconic acid production, which increases body.
2. Macro-oxygenation. Introduction of large doses during fermentation. Very little tannin reactivity results. Purpose is to promote yeast health and complete fermentation. H2S my also be diminished. As you know, there are three phases.
3. Micro-oxygenation (in French, it’s microbullage, or “micro-bubbling.”). Post-fermentation introduction of continuous low dose at a level lower than or equal to the wine's ability to react up the oxygen, such that no DO (dissolved oxygen) buildup occurs. Its purpose is to stabilize color, produce a refined enlarged light tannin structure which integrates aromas, increase longevity and balance reductive strength. Oxygen is the wire whisk in the tannin soufflé.
We speak of three phases of MOx. Phase I occurs between the day of dryness and the addition of SO2 post malolactic, and is the time when color is stabilized and 90% of oxygenative structure-building can occur. Phase II occurs post ML post SO2, and either substitutes for or prepares the wine for barrel ageing. It is principally engaged in refining texture, balancing reduction, and completing aromatic integration of vegetal, oak and microbial aromatics. Phase III occurs when wine is removed from barrel for final refinement and harmonization, which may include softening of green oak tannins extracted late in barrel ageing.
OenoDev’s method for accomplishing this is to drop an ultra-fine filter into the wine and feed it with a precision doser. I got to introduce these very serious Frenchmen to Don Ho’s “Tiny Bubbles In the Wine,” now available on their answering machine. Getting them to bust a gut stands as perhaps my professional life’s most purely joyful accomplishment.
4. Violent oxygenation or "clique-age." Named after the “clique” noise the remote solenoid makes when you drop the bubbler into the next barrel. Occasional punctual introduction of oxygen (over seconds or minutes) during ageing. Does not build structure, but rather breaks it, softens tannins and decreases reductive energy to promote early release. Equivalent in woodworking to sanding and polishing.
I admit it – I’m pissed off. Jerks all over the planet are trying to associate themselves with MOx without giving Patrick credit, but worse, cashing in on its sex appeal while selling junk machines whose poor performance discredits and pollutes his message, or publishing braindead research which distorts enological comprehension of his rediscoveries of the nature of wine. (List of jerks available on request!)
Ducournau’s real accomplishment is in elucidating the development of structure, which he calls “élevage” – the French term for raising horses or children – NOT a passive, non-interventionist process, right? Use of oxygen is just one element – it’s the wire whisk we use to create the rich light tannin meringue. (One could also say it’s what the Aztecs taught the Belgians about converting cocoa powder to chocolate through “conching” ) The whole system also incorporates a mastery of the seven functions of oak as well as an understanding of lees re-incorporation, which is analogous to the Swiss discovery of milk chocolate.
Some principles of oxygenative structuring:
1. Timing is paramount. The same wine which can be worked at 60 barrel equivalents in November can only take 5 in January.
2. Ripeness is critical. Underripe fruit contains too little anthocyanin, but in overripe fruit the color has already oxidatively polymerized and is of no use for enhancing structure.
3. Color is essential to structure. The more anthocyanins in the phenolic mix, the finer the structure and texture and the greater the aromatic integration.
MOx performed just after fermentation works to stabilize color polymerization. Anthocyanins which are in solution are easily attacked by yeast enzymes and other means of precipitation. Oxidative polymerization ties them up into stable forms. These color molecules cannot polymerize further, and act as "bookends" on the polymer. Thus the more color, the shorter the chain, and the finer and more stable the structure of the resulting polymers and the colloids they form into. That's why syrah is softer than pinot, even though it has much more tannin.
The results of properly done MOx are aromatic integration (veg, oak and microbial aromas integrated into the background around a central characteristic fruit expression), color stability, finesse, volume on the palate, reductive balance, and graceful longevity. And all we needed to do was exactly the opposite of what our scientific enology masters taught us in school.
We tried for a decade to develop instrumental analytical methods to guide our work. We gave up. In the end, we decided it was better to require the winemaker honcho to show up and taste with us. Perhaps the greatest benefit of OenoDev’s techniques is that it forces winemakers out of their offices and don to the cellar floor. Working with oxygen obliges every wine to be tasted and discussed three times a week – a huge imposition on the typical corporate winemaker, but also huge fun.
You can read about our sensory system on www.vinovation.com. Have patience and stay tuned – I’m working on some multimedia presentations to bring it home to you winemaker types. Meanwhile here’s a sense of it.
We drop a diffuser in new wine the day it goes dry. Then we drive the car according to how the wine reacts, checking back in every couple days.
If the wine is getting too much oxygen, it usually smells of acetaldehyde (a sort of stale appley smell, not to be confused with ethyl acetate, which is the vinegar smell). If there is lots of pigment in the wine, though, the aldehyde is consumed as fast as it's made (it's oxidized ethanol) by bridging color molecules onto tannins, so you don't smell it. But if you're going too fast, the wine becomes fruit-forward in a way resembling tawny port or hazlenut. We call this "open aromatic expression." Thirdly, too much O2 results in dissolved oxygen build-up, which we measure with a gizmo.
Young red wine is incredibly reactive and resilient. All of the effects above are temporary, and if we react too much to them, the wine will become reductive in a few days: sulfide aromas, closed aromatic expression and apparent vegetal aromas. All just temporary indications that the wine is more reactive and needs feeding. Correct feeding makes these effects even stronger, like you're making a monster. Only after you get "over the hump" after a month or two do you begin to quench the wine and balance reductive strength.
A barrel gives approximately 1 ml of O2 per liter of wine per month -- I call this a "barrel equivalent." A typical Napa Cabernet will take 60 or 80 barrel equivalents in the first month of its life. If you wait until after ML and SO2 addition to start, that same wine will only take about 3. If you have used oxygen properly in Phase I, then after ML that same wine will take 5 or 6 instead of 3, and will age 6 to 12 months longer in barrel.
When we hang those same grapes too long, they can't react to oxygen, because the polymerization has already occurred on the vine. We're trying to make a tannin soufflé, but the eggs are already scrambled, so it's impossible. Wines like this will only take up maybe 10% of the oxygen in Phase I of their properly ripe counterparts harvested from the same vineyard two or three weeks previous. They may taste nice and fruit-friendly in youth, but they will deteriorate much more quickly in the barrel and in the bottle.
Further discussion of MOx is available the Vinovation website.