Reductive Strength

Your RedOx Redux chapter on reductive strength & Vern’s Warburg apparatus was one of the most eye-opening chapters in the book.
I’ve read it 4 times now and still trying to fully understand it.

As I understand it, the Warburg thing can actually measure a wine’s total oxygen uptake capacity over its lifetime. That seems, on the surface, to be
a measurement that any winemaker would be dying to have. Yet I gather that is something that has been hugely ignored by the winemaking community??
Has there been scant interest in this measurement by winemakers??

So…a few questions:

  1. You state that 90% of a wine’s reductive strength can be lost to field oxidation, leaving the grapes to hang longer on the vine. Three weeks longer
    costs you a decade of cellaring longevity (not exactly sure where those numbers come from?). That seems pretty significant to me.
    What if your grapes are sitting out there at 20Brix and you’d like to get it up to 22-23 or so. You don’t like the flavors yet. The weather is not cooperating.
    Does this mean that you have to rob the resulting wine of its longevity by leaving the grapes to hang so you can get riper flavors you seek?? What’s
    a winemaker to do in this case?

  2. It’s been often stated by the wine geeks that these wines that are being made from overripe grapes w/ longer hang times, giving higher alcohols
    (we’re talking PasoRobles here I think), don’t age well and fall apart at any early age. Does the Warburg measurement confirm this claim; that high alcohol
    wines will not age?? What about a wine that was made from very ripe grapes but has been RO’d to knock the alcohol back? Does Warburg confirm that
    it has a better potential to age longer because of the lower alcohol??

  3. It sounds like this Warburg measurement is not an easy thing to carry out in a winery. Does anbody, like Leo’s Oenoligix, offer up the service of providing these

  4. If you are a winemaker, would the Warburg measurement be something of use, as good as your own palate and yrs of experience, to making your estimate
    of longevity for that wine? Would it be something PaulDraper would find of use for MonteBello?? Would it tell Paul something about this yr’s MB that his
    palate may have missed?? Or is the Warburg something that’s never going to supplant Paul’s palate?

  5. You have two wines with the same Warburg measurement in the btl. Ignoring any variations in cork leakage/etc; there is still no way to guess which one
    is going to be the “better” (whatever that may mean") ten yrs down the road. Is there??

Probably have more ??, but will stop there.

There’s also another new analysis I just explained on the “Stability without SO2” thread. A huge game changer made possible by the new Nomasense technology.

This is a photo-optical system which reads an O2-sensing dot glued to the inside of a bottle and capable of reading the O2 inside without opening the bottle.

We simply fill with a bulk wine sample, newly made or ready to bottle, and place in an argon atmosphere at constant temperature and read the dissolved oxygen (D.O.) over time.

It turns out that fragile whites consume around 0.1 mg/L per day, which young, robust reds will take up as much as 1.0 ppm per hour – a thousand times the reactivity! This information is critical to informed decisions about shelf life, reduction potential, proneness to oxidation, closure choice, blending options, barrel time, release dates, and even ripeness feedback.

The analysis is in the ISO certification process now and being beta-tested to determine what the slopes mean for various varieties. We are recruiting interested beta-test partners now.

In case you don’t already have all that you need, I am happy to participate in the beta of your 02 test.

Indeed. It’s baffling to me that reductive strength was hardly mentioned at Davis when I was there. Reduction was just a defect, a spoilage to be treated. Today, I consider it a very good sign, and I use the wine’s reductive energy to work with its structure. Today I worry about wines that AREN’T reductive!

The growing awareness of reduction is a recent artifact of better grapes, more living soil practices, screwcaps and technical tools which allow us to get more perfect ripeness, all of which have formed a perfect storm. We’re victims of our own success. It certainly is peculiar that R-G worked out the Warburg flask 80 years ago and nobody’s doing it.

The numbers come from the integral under the Phase One MOx curve. A typical properly ripe Napa Cab will take 60 mls/L/month for four weeks. One held to excessive hangtime might take 30 mls for three days. It’s an obvious order of magnitude decline in reductive strength.

I’m sure I don’t have to tell you that the result is the wines have big alcohol, lots of raisiny fruit, quite appealing to newbie collectors who are looking for flavor impact, especially when dressed up in some nice rich French oak. Pretty disappointing five years later when the wines are dry and dead.

There are halfway measures. The Australians are masters of flirting with field oxidation without actually bottling time bombs.

The picture you paint is incorrect, though. Typically, California Cabernet isn’t properly ripe until you’re up around 25 brix (ripeness actually has nothing to do with brix, and years like 2010 and 2011 gave us overripe wines at 23.5, but that’s unusual.) This is where I like to pick, then bring the alcohols down with RO into the 13s. But those wines are very reductive, so winemakers who haven’t been trained in harnessing reduction as a force for good will field oxidize by hanging into the raisin realm in the very high 20s and beyond. Some even add high proof. Scott Harvey did a tasting where a dozen Napa cult Cabs measured over 17%, except one that was 16.9%.

We haven’t been working with the apparatus long enough to know these things. Right now we’re still perfecting the methodology.

It is a super easy thing to do in a winery. Nobody offers it commercially, least of all Leo, who has his own secret stuff he standardized on twenty years ago.

I guess you’d have to ask Paul.

I think the numbers will be useful, but we all have to play around with this and other new assays for a while before we can draw these sorts of inferences and conclusions.