Putting a stake in the heart of "slow ox"

Ask how to handle a particular bottle before drinking, and someone is bound to suggest “slow-ox”. In a recent discussion of slow-ox, and breathing/decanting in general (here: The myth of letting wines breath) I argued that slow-ox can’t work because the diffusion of oxygen into a bottle (and, conversely, compounds which might escape the wine beneficially) is much too slow to make a difference to a bottle just sitting open for a few hours.

Just a little digression on diffusion (apologies for the didactism): It can be tricky to differentiate between diffusion (movement of molecules through random motion) and convection (bulk movement caused by other forces). In daily life, we experience bulk movement all the time, but don’t really notice diffusion. A breeze through the window carries the smell of your neighbor’s barbecue through the house; someone walking through the room pushes air around and causes bulk movement; dumping an ingredient into a pot, or milk into your coffee has inertia that stirs things up, or sets up temperature gradients or forces between layers with different densities that move things around quickly; the fan in your oven blows air across the food; Those are all examples of convection. Visualizing diffusion isn’t easy, partly because the things we notice moving aren’t doing so (mainly) because of diffusion; and partly because things that actually are diffusing are doing so at a rate too slow to notice. When you take the lid off the pickle jar and smell pickles, it’s not really because of diffusion, it’s because you sucked some of the pickle aroma up into the air with the lid, and some of that wafts past your nose. You don’t smell the pot of stew on the stove because of diffusion, you smell it because the hot steam is rising and creating bulk movement of air.

Diffusion is a slow process. Glacially slow in liquids, but relatively slow even in gases. For an oxygen molecule in water at 20 degrees C (68 F), the diffusion coefficient is about 2x10-5. Use the online calculator below to calculate how long it would take for O2 to travel, say, 10cm in water. It’s about 29 days. That’s days, not seconds, minutes, or even hours (in air, where the diffusion coefficient is roughly 10,000 times larger, it’s still about 5 minutes).

This is why the alveolar capillary wall, where oxygen is transferred from your lungs to the capillaries that will carry it into your system, is about 0.6 microns thick. Much thicker, and there wouldn’t be time for oxygen and CO2 to diffuse across. It’s why we have a microscopic network of tiny capillaries to carry blood to our tissues - because without that, diffusion alone cannot support life on the scale of a large mammal. It’s why you use an aerator in your fish tank, or plants which produce O2, or agitation of some kind - because diffusion alone can’t bring in enough O2 to keep fish alive in a larger tank.

When you pull the cork on a bottle and just let the bottle sit, there is no bulk movement of liquid in the bottle. Anything that goes in or out must diffuse across the air/liquid interface. Oxygen must cross the barrier, then diffuse throughout the wine to do anything. SO2 or other volatile compounds must diffuse through the length of the bottle to the interface, then escape. And there’s the rub: diffusion is just too slow to make a difference in a bottle of wine. Without agitation, bulk movement, and increasing the surface area greatly, almost nothing is going in our out of that bottle on the scale of minutes, or even hours. You may be able to smell some compounds that have a threshold of human detection down in the parts-per-trillion/billion range (because, like everything else in chemistry it’s all about probabilities, and there are bound to be a few molecules with a lot more energy that can bounce around and escape faster), but you’re not going to get any appreciable amount of O2 in, or other compounds out.

If you still doubt this science, maybe some 1000 word pictures will hammer it home. I scratched my head for a while trying to think of an appropriate demonstration with something you can find around the house, and came up with brown sugar dissolving in water, because it’s easy to visualize. I put about half a teaspoon of brown sugar in a glass of room temperature water, and just left it to dissolve and diffuse. Took a couple of days for the sugar to fully dissolve, and after 4 days, you can see how far it has migrated through the glass (about 3 cm). I was concerned that maybe the color is contained in larger particles that would tend to settle at the bottom, so I did the same with another glass, but stirred it up until everything dissolved. Nothing has settled out, and the color is uniform from top to bottom of that glass.

First day

2 days

4 days

Now, sugar is a larger, more slowly diffusing compound than O2. But the result above is quite consistent with what you get from the online calculator.

The good news is that opening that bottle and leaving it to “slow-ox” won’t hurt anything, so if you remain unconvinced, go on slow-ox’ing, you’re not losing anything by doing it. And if you do, don’t leave it in your cellar, get it on the table at room temp, because diffusion slows down even more as temperature drops.

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I think correct comparison would be if multi-hour diffusion that is then poured into new glasses provides a meaningful difference vs a freshly opened bottle that is poured into new glasses. I think your analysis would be correct if someone was taking a long straw and drinking directly out of the bottle - which few of us do with any regularity. Not saying results will be any different but think problem needs little refinement

I’ve posted a link to a similar calculator in the past. Even if you poured off a 3oz pour to increase the surface area it would take almost a month for the oxygen to traverse the length of an upright bottle.

However this would also mean you can keep a bottle for at least a week or two after it was opened and there are many people who swear that a wine is no good after being opened 24-48 hours.

I guess the counter argument would be that you don’t necessary want 100% oxygenation of a bottle of wine as that would mean it’s oxidized. Maybe you only want/need 1-3% oxygenation for a wine to change or “open up”. This would result in a much shorter necessary exposure time.

Alan,

A thoughtful and interesting post.

My criticism would be that simple diffusion does not at all account for the mechanism of oxygen transfer through a bottle of wine, only the movement of oxygen into the most superficial layer of wine at the neck of the bottle. Beyond that, you have subtle effects that cause that diffused oxygen to be transferred from one area of the bottle to another, from convection, Brownian motion, and tenets of fluid dynamics that are beyond the comprehension of my simple primate brain. There is no perfectly still bottle of recently opened wine in any of our cellars…

I’ve noticed that, esp with structured Pinots, a small amt of air over a longer amt of time works much better than pouring into a decanter, esp a wide bottom decanter. E.g. double decanting a small glass of wine (the recommendation of a few burgundy domains). or pulling the cork, inserting it again and inverting the bottle (or on its side if there’s sediment). I first experimented with this using quite a number of bottles of 1999 St Innocent Seven Springs and Freedom Hill Pinot Noir. They were fantastically unapproachable on PnP, yet were equally uninteresting after decanting. Double decanting a small glass in the morning yielded the best look into what they would become. I opened a bottle of each last year…quite good yet still young.

In my experience, descriptions of the ‘slow-O’ method I’ve seen include taking a taste…the pouring gets some air into the wine, the top quarter or so. And given my prior comment, it’s having a small bit of air/o2 for an appropriate amt of time that matters, not the amt.

Second, you’re trying to prove a negative which, in general, is fantastically difficult to do (i.e. to prove that slow-O can’t work). That, coupled with our limited understanding of the chemistry of how wines age (in a broad sense + esp great wines) makes me think that your comments, however interesting and possibly reasonable, won’t be the last word on the subject.

Experiment:

Open a bottle of seltzer, let it sit for several hours.

Notice any differences?

Try it with orange juice.

What are you really trying to accomplish? Is it to demonstrate that “slow ox” accomplishes nothing? Ultimately theory needs to agree with experiment and be consistent with observation. If not, well, you’ve got some splain’in to do about why that disagreement exists. A significant number of people have experience that wine improves with exposure to air (whether slow ox, decanting, etc). Writing off a mountain of observational experience as some sort of mass placebo effect, while pointing to O2 diffusion rates, isn’t a particularly satisfying explanation that’s likely to drive behavior.

So it takes a month for O2 to diffuse 10cm in water. I’m sure you’re right. If you want to extrapolate that to a slow oxed bottle being unchanged according to the “sensors” in a human palate after a few weeks of being open on the counter have at it… with your bottles. Or better yet, do a few triangle tests to validate your hypothesis. That would be deeply more satisfying then theory alone which, however self consistent, makes a number of simplifications about what’s in reality an enormously uncontrolled experiment. All sorts of trace components can and do matter, and all sorts of handling procedures occur during and often after opening.

An explanation would be nice and a framework even better, but having my bottles show well is nicer… ultimately it’ll take much more to convince me to open them any way other then the way that experience tells me works best.

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Interesting point. As a lawyer, not a scientist, what would the the mechanism causing this change that is not present in slow ox?

Pretty much the entirety of this thread so far is predicated entirely on the notion that interaction of oxygen with the wine is the only mechanism by which wine evolves after opening. This is totally incorrect.

What are the other mechanisms? (serious question)

I’m with Noah on the flaw in the diffusion metaphor. As you (Alan) have helpfully explained in some detail in the prem-ox thread, the interactions between sulfur, oxygen, various types of acids, and the soup of complex organic molecules in wine is a dynamic and energetic process that far surpasses basic diffusion dynamics.

When people talk about bottles going south after 24-48 hours they’re talking about partially drunk bottles, not bottles uncorked and left full.

You take yer science and yer fancy book learnin’ and you go straight to hell. There’s no room for facts here, just subjective experiences unswayed by logic or reason.

If you fill a bottle up to the top it keeps for a rather long time. Put a drop of wine in a bottle (therefore having a majority of air in the bottle) and the wine will oxidise rather rapidly.

“Oxygen is absorbed in water by direct diffusion and by surface-water agitation. Solubility of oxygen in water is so small and by diffusion process alone in still water, it was culculated that it would take 6 years for oxygen to diffuse from surface to a depth of 6 meters in quiet water. Absorption of water is very minor, that almost all the oxygen enrichment of natural waters takes place by agitation of water.”

http://www.fao.org/docrep/field/003/AC183E/AC183E04.htm

Published papers characterizing the role of surface agitation in oxygen absorption have been out there since the 1950’s. (E.g.: http://onlinelibrary.wiley.com/doi/10.1002/jctb.5010051008/abstract) I think there’s an obvious argument that pouring a small glass off the top allows enough surface agitation to markedly increase the amount of dissolved oxygen in Wine.

N

Alan is the Galileo of Wine Berserkers. Heretic!

Did anyone tell Alan that we are dealing with “Wine” and not “Water.” He needs to start his calculation over to account for the alcohol and other compounds in “Wine” that totally change the equation. [snort.gif] [neener.gif]

Alan’s theories on this seem more likely than previous group think , but Noah raises good counterpoints. Of course no real damage is done by slow-oxing,so on balance you’re probably better off doing it.For some reason, I never really seem to remember to do it.

mmm…so what are you trying to say? [bleh.gif]

For the win.