Franc-ly Puzzling

As I wrote a few days ago, the Cabernet Franc — long our favorite wine from our grower — wasn’t its usual self at last racking. While it’s been dependably fresh and lovely any time we pull it from barrel, last week it was dull and flat, seemingly absent the will to live. A little unsettling, to say the least.

Today I got back some lab results from our long-suffering friends at ETS Labs, so we have a better picture of what’s going on with this sullen teenager. But even as the data answers some questions, it raises some others.

Stroke your beard and consider a theory or two with me after the jump…

Here are a few theories as to why the Franc tasted the unusual way it did, as well as a few ways we could cope with it.

Proxycarb infection
George floated this terrifying theory, and some queries to a few winemakers did indeed confirm it as plausible. Thankfully, the data suggests this didn’t in fact happen.

Like many wineries, we use Sodium Percarbonate (or “proxycarb,” as jaunty abbreviators abbreviate it) to clean our equipment — it’s an environmentally-friendly, water-soluble chemical compound of sodium carbonate and hydrogen peroxide (H2O2), and the miracle ingredient in the oxygen bleach OxiClean. To oversimplify, proxycarb is powdered oxygen, molecularly unstable enough that on contact with water, its embarrassment of oxygen molecules jump ship to anything nearby, effectively changing that thing’s chemical make-up to produce thing-ending results — whether that’s a stain or a microbe.

The reason why proxycarb is touted as “environmentally friendly” is that in the end, it quickly decomposes to water, oxygen and sodium carbonate (or “soda ash”). But it doesn’t break down immediately, so George’s theory was that if someone hadn’t rinsed a vessel or hose thoroughly, we’d in effect be adding a lot of oxygen to the wine. And that would indeed flab it out, big time.

Thankfully, the ETS results suggest this, at least, didn’t happen. The current pH is in fact the same as it was a few days after crush (3.72) — if it had been significantly higher, that would have been a strong indicator of (proxy) ‘carb-ination.

Nevertheless, now that we know how dire the consequences could be, we’ll be even more rigorous in our cleaning regimen, so this is a good (if heart-stopping) wake-up call.

Malolactic fermentation
After the raucous joy-ride of primary fermentation is over, a secondary fermentation usually follows quietly behind, mumbling to itself as it sweeps up the confetti and converts malic acid to lactic acid. That in effect softens the wine, since lactic acid is not as harsh as malic acid.

So, another theory holds that could have happened here: the wine we tasted in March, perhaps, was still working through ML (it’s usually a slow process, since it typically over-winters) and still therefore had some verve. As spring progressed and the weather warmed, ML could have finished up so that by the time we tasted the Franc again, it had softened considerably.

The problem with that theory is another number ETS gave us. The total acidity (a measure of all the organic and inorganic acids in a wine) of the wine a few days ago was .55 grams/100ml. That’s not too bad — could be a little higher, to be sure — but it’s neither disastrous nor low enough that it would render the wine flat and lifeless (typically, red wines hit around .6-.7 g/100ml).

But what’s truly bizarre is that this number — .55 — is higher than it was after crush back in the fall. Since malolactic fermentation lowers total acidity (lactic acid is “monobasic,” half the acid its manly malic sibling is), this could be an indication ML hasn’t in fact swept up yet. Nevertheless, whether it’s happened or not, acidity never goes up, so this number is a head-scratcher.

I’ll be running paper chromotography on this wine this weekend, but in the meantime, WTF(ranc)?

Wild yeast
One signature difference between all our previous Cabernet Franc ferments and this one is that this year, we didn’t pitch any yeast: we let wild yeast have their way with our wine. In previous years, we pitched the evocatively named “71B,” a yeast “designed to isolate yeasts that would produce a fruity yet fresh character in wine that would live long after fermentation.” The 71B did just that to our Franc.

So it’s certainly possible that the motley mob of wild yeasts didn’t achieve as pin-point a result as the 71B. I’ve also been told wild yeast ferments don’t really show their stripes until at least the spring after harvest, so that could also explain the wine tasting good in March and less so now.

I really don’t know how we’d test this, however, so it’s something of a moot theory.

This one’s laughable, considering the damp, cold spring we’re still more or less enduring here in July. But through the winter, one of the differences between the Franc and the other barrels is that it was stacked on top of the others, effectively positioning it about 4′ higher than its siblings. Because heat rises, and because at that level the Franc would be essentially above the foundation, you could argue that the environment it aged in was warmer than that of the other wines in our stable.

But yes, so slightly as to be negligible. To be on the safe side, however, we repositioned the Franc on the floor like the other barrels at last racking.

Sulfur Dioxide
Again with the chemicals! What are we aging here, a superfund?

Sulfur Dioxide (or SO2) is chemical compound virtually every winery on the planet adds as a preservative to ensure clean, long-lived wines. It essentially binds up oxygen — a friend to you and me, but also to wine-despoiling microbes, if not premature aging.

What our results showed were that there’s virtually no “free” SO2 left in the Franc. Free SO2 is the shiftless brother-in-law of “bound” SO2 in a wine, sleeping on the couch, drinking straight from the milk jug and walking around in its underwear until oxygen tries to break in — at which point it drops the Wii and goes Jean Reno on that allotropic sucker. That our wine has virtually no free SO2 means that only tannin and acid are protecting it — and as you saw above, our acid level isn’t stratospheric.

So obviously, we’ve got to add SO2, and don’t spare the tires. The wrinkle is that we’re just a few weeks away from blending, and adding SO2 always seems to close up and dumb down a wine for a while — in other words, rendering it useless for near-term blending.

That said, as he eyed our especially low SO2 level, our man at ETS did mention anecdotal evidence that the right SO2 addition can in fact bring a wine back to life. If that’s true, then we’d get protection and liveliness with one stoke, making it easier to rationalize a possible delay in when we blend.

So, thinking about all the above, I’m tempted to try a little SO2, perhaps in conjunction with a slight acid addition, and see what happens. Any thoughts?


7 Comments so far

  1. Les Blog » 2007 Chromo results July 20th, 2008 12:22 pm

    […] Franc, whose results indicate malolactic is over and we can therefore trust the acid numbers we got earlier. So in the next day or so, I’ll be adding SO2 and some acid to try to perk up our old […]

  2. Le Kraut du Cote de Soleil August 3rd, 2008 3:11 pm

    Matt, You probably already did this, but what do you suppose the sulfur dioxide might react with in the wine to “liven” it up? I cracked open one of my old chem. textbooks and it seems like there are a couple of possible tendencies. One, the sulfur dioxide will combine with some oxygen and water to produce trace amounts of H2S04, or it might suck up oxygen to make sulfur trioxide, which would dissipate as a gas. What exactly are you trying to accomplish here? (This is coming from someone who knows next to nothing about wine-making but probably way too much for his health about chem.)

  3. Le Kraut du Cote de Soleil August 3rd, 2008 3:15 pm

    Also, it seems like both the yeast theory and the heat theory could be pretty good, as even a degree or two of difference can significantly change any fermentation or acidification process.

  4. Le Kraut du Cote de Soleil August 3rd, 2008 3:18 pm

    Er, one more comment. Why can you not just add the SO2 and some acid and just wait a while to do the blending? Is it because the other ingredients will be at their best? Can you slow them down or put them in some sort of stasis somehow?

  5. Ziraud August 3rd, 2008 4:11 pm

    Thanks for your suggestion, Herr Kraut. That you even have a chem book to crack puts you way ahead of any competence I might have with chemistry.

    I think, though, that the theory might be that an oxidized wine tastes flat because oxygen has taken over the wine; therefore, keeping oxygen at bay by binding it up could potentially augment a feeling of liveliness.

    I know that too much sulfur spray in the vineyard too close to harvest can mean that once the grapes are in and fermenting, the result can definitely be H2S04 (with its delicious rotten egg smell), as you suggest. Post ferment, your chem analysis also underlines that we have to be judicious in how much sulfite we add along the way. Anyway, no egg-scrable wine yet…

    I wonder if what you’re indicating as possible results happen in order: up to a certain point added, your reaction is SO3, but after a while, it’s all bound so you get H2S04?

    I tasted the Franc last night, after both S02 and acid adjustments last week, and it’s definitely better. A post on that soon…

    Thanks much for your comments!

  6. Ziraud August 3rd, 2008 4:18 pm

    And to answer your question about adding all that stuff later, I think you’re on the right track about balance — if the Franc’s not the wine we’d like it to be, we’d blend with it in its less than stellar state. Esp if the Franc could be improved, that would mean we’d have a skewed blend.

    I know a lot of winemakers have told me that you want to add acid as early in the process as possible, so it’ll have time to integrate into the wine and not just taste like a bunch of acid on top. The best time to do that is during fermentation, which is way in the past, of course. But certainly, getting it in there now so it has at least a month or two to think it over before bottling will probably help.

  7. Le Kraut du Cote de Soleil August 3rd, 2008 6:41 pm

    I guess I thought that you might be experimenting with blended wines, and was wondering if there was any way to “slow” down other barrels or batches so that one could add something to the “flat” wine and adjust it. Any thoughts on this?

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