Petillance or spritz in a still wine

[Al_Osterheld]

An added thought: during fermentation where you’re actively producing CO2 that’s bubbling out at the surface of the must, there is a blanketing effect because it takes time for the collisions to spread the molecules around, and this diffusion timescale is slow enough compared to the CO2 production timescale so that very high CO2 concentrations near the must can be maintained. This is analogous to squirting CO2 into a bottle as mentioned above.

-Al

[Al_Osterheld]

FWIW, I’ve never confused acidity and spritz. Every time I’ve suspected it, the shake test shows there is excess dissolved CO2.

-Al

[G_D_y_e_r]

@Peter Cargasacchi

Many, many times the perception of spritz is the result of acidity in the wine. It’s a tactile sensation from the interaction of acid with mucosal tissues in the mouth. Some people are more subject to it than others, but I’d say at least half the time someone thinks a wine is spritzy, its not. Similarly the perception of minerality in many if not most cases is driven by tho tactile perception of acid and even tannin interacting with mucosal tissues in the mouth. The difference being the difference between actual flavors vs. what is tactile. Examples, bitterness is a flavor, but astringency is tactile and not flavor.

I’m definitely familiar with this sensation and have usually associated it with high acid. The spritz I originally posted about is not the same thing as the high acid tingle.

[John_Morris]

@Al Osterheld

An added thought: during fermentation where you’re actively producing CO2 that’s bubbling out at the surface of the must, there is a blanketing effect because it takes time for the collisions to spread the molecules around, and this diffusion timescale is slow enough compared to the CO2 production timescale so that very high CO2 concentrations near the must can be maintained. This is analogous to squirting CO2 into a bottle as mentioned above.

-Al

Indeed, occasionally workers have suffocated when they’ve fallen into vats. And I remember once sitting out at Ravenswood next to plastic bins of freshly harvested grapes that had begun to ferment. The surface was covered with bees or wasps that had suffocated.

[Rick_Allen]

@Al Osterheld

"CO2 is heavier than air/oxygen so a layer of CO2 will sit on top of the wine, keeping oxygen away. " This doesn’t work. At any reasonable temperature (one where you will survive), collisions between molecules will keep the CO2 so thoroughly mixed in the head space that it’s uniformly mixed from a practical standpoint. Gravity could produce concentration chances with differences in altitude, but only over large distances (eg, several kilometers to change relative concentration by a couple tens of percent). Also, it doesn’t separate the gases into layers, just produces slow changes in concentration as a function of height. (If you squirted CO2 into an empty bottle, it would initially flow to the bottom but then the collisions will distribute it throughout the bottle. This is why people think there is a blanket effect.)

-Al

Al,
Does this hold regardless of pressure? The reason I ask is that I generally will not totally purge my tanks of CO2 before I pressurize (~10psi) them for filling, and I usually don’t fill them until the next day or later. As I push beer into the tank under pressure (I then bleed from the receiving tank), it always seems that I get air coming out for the first barrel or so (out of a 9 barrel tank), and then I get CO2. How long does this mixing take?

[Al_Osterheld]

A static situation, like wine sitting in a bottle, would be qualitatively the same at higher pressures (actual numbers different, effects are the same). While I don’t know very much (anything?) about beer production, you’re describing a dynamic situation like fermentation. Pushing the beer into tank probably causes it to release CO2 and it will initially stay towards the bottom of the tank, near the beer-air interface, until it diffuses (in this case it also would mix because of the air currents caused by pumping in the beer). How long does it take to mix? Depends on the distance over which the mixing needs to occur and the level of mixing you want to define as “mixed”. For CO2 introduced quiescently into the bottom of an empty bottle, I’d say something an hour for it to be reasonably well mixed. Over the distances and in the situation you describe, the time to mix purely by diffusion would be several times longer, but I suspect there is a lot of turbulent mixing from the pumping.

-Al

[Wes_Barton]

@G. D y e r

Are there any funky aromas associated with the spritz? Wondering if this trapped CO2 as mentioned above, or some small in-bottle fermentation. If it doesn’t taste/smell bad and decanting/shaking solves the bubbles, then no harm, no foul I suppose.

In addition to what’s been said, it can also be produced by “bad” yeasts or bacteria, which would produce off odors. I gather this was historically more often the case. Cleanliness pretty much eliminated that issue.

Filtering can eliminate any living yeast and bacteria cells, preventing a secondary fermentation. (Though I’d generally prefer the unfiltered wine and accept the risk.)

For wines that are vulnerable to a secondary fermentation, proper storage is imperative. Temperature and time are the factors that can get it going. (I guess you could say with some wines the intent was to leave them vulnerable. That would make petillance in them a provenance flaw…)

[DougS]

I’ve only encountered this a few times in red wine. In 2 out of maybe 3 or 4 wines, I found the problem in multiple bottles and I believe (as do several others) that it did affect the flavor for the worse. I guess if I can shake it out or decant it out and the wine tastes fine, I’m okay with it, but I would worry if it were a wine that I was planning to hold on to for some time. I’ve also seen it in quite a few German Rieslings and never had a problem with the flavor of those ones.