+1. In this case, as Kyle says, ML happened, or they left residual sugar and it re-started. Or both.
CO2 in bottled still wines, red or white, is almost always simply left over from fermentation. If responses on this kind of thread were proportional to reality, most comments would say - dissolved CO2, it’s harmless.
You typically find it in younger wines that didn’t age for years in barrel and/or bottle, where things would have worked themselves out. And you find it with producers that do what I think most of us like - little or no racking of the wine, cold cellars, etc. It’s simply a product of not forcing it out of the wine, especially when that CO2 helps protect against oxidation and may even allow the producer to use less sulfur at bottling.
If you have mL in bottle - and that’s so much more rare than responses in threads like this suggest - you’ll likely notice cloudiness or a pearlesence, and a stink, just like mL happening appropriately in barrel.
Really, if anything’s active in the bottle and causing a sparkle, it’s usually brett. Even then, I find fizzy, bretty bottles to be pretty uncommon. Usually only the worst brett offenders get to that point. Brett is common, really fizzy bretty bottles not nearly as much.
Some white wine producers will actually add a bit of CO2 to their wine to increase brightness on the palate, when the naturally leftover CO2 isn’t enough to their liking.
I get some people don’t like any sparkle. I just think people might feel differently if they were more confident that what they were experiencing wasn’t activity in the bottle, but just left over CO2 that’s harmless, even helpful in some was. I know that was my experience back when I first learned about this. I worried something was wrong, so I didn’t like any sparkle. Then I learned that mostly nothing is wrong with it, and when it is from a problem in the bottle, the fizz isn’t the issue, it’s the cloudiness, the mousiness, whatever. I came to see that sparkle was actually fine - cellar time takes care of it, decanting, even swirling.
If you feel differently, that’s cool. I just found it helpful to get over my resistance to it by realizing it was more about my mistaken fear that something was wrong, when everything was fine. In fact, the wine was less processed and I wanted that and I just had to learn a bit more to feel comfortable about it.
Most comments in this thread do say that dissolved CO2 is harmless and the responses to the OP said exactly that. Other people asked about more fizziness and in those situations, like the above photos, it’s not dissolved CO2. It’s secondary ferm.
I understand the distinction between dissolved CO2 and a secondary fermentation, having seen both in wines over the years.
But if you simply don’t like your wine to be fizzy, particularly in my case a red wine like Copain P2 and where the fizz was so significant that you couldn’t dispel it with shaking, swirling or aeration, then I don’t think there is anything irrational or ignorant about considering it to be a flaw or a negative in the wine. I don’t buy still red wines aware or desirous of them being fizzy. If Vincent or others like red wines that way, that’s fine with me, but I at least think the buyer should be made aware of that condition before buying them, rather than having to deal with the considerable surprise when you open one.
I can see why you’d be unhappy with spritz in a red, Chris, if you weren’t expecting a Lambrusco or some such. In whites, a little CO2 is so common that I wouldn’t cry foul about that – certainly not in a German.
I guess I see enough suggestions if not declarations of mL in bottle or refermentation that it’s fair to say more emphatically - it’s really not that common.
And are you sure about that diagnosis of the pictured bottle?
Again, if people don’t like any CO2 in their still wine, that’s fine. I didn’t but then I learned to understand it differently and my feelings changed, and I think that’s worth adding to the conversation. (I’m not saying anyone is ignorant, by the way. Knowledge is a continuum, not a zero sum, win/lose thing where you either know something or you’re ignorant).
And I’m not talking about lambrusco levels of fizz. I’m talking about the OP’s suggestion of a “fleeting effervescence” - great, great phrase by the way.
If its trapped CO2 elevation will also impact it
Vincent: the OP’s situation was dissolved CO2. No big deal at all. The photos are not dissolved CO2. They’re some kind of secondary ferm. If they’re not, the wine maker needs some advice. 
Beaux Freres intentionally bottles with elevated CO2 because they feel it allows them to use less SO2. Not sure how the photo compares to typical level in one of their young wines. But if it was from fermentation in the bottle, there would be fermentation odors (beyond just the CO2).
-Al
The pictures look to me like the bottle was shaken vigorously while 2/3 full. We just opened six bottles of Beaux Freres 2006-2008 and none had fizz, bubbles, etc. Could be that the bottle in question had some bacteria in it when the wine went in, but I’ve never seen a Beaux Freres do that before. Crazy pictures!
Nope. The first pic was taken after we opened and simply poured.
In fact, the cork ‘helped itself’ out of the bottle as we opened the wine.
We’ve had some bottles do this, and others not.
It was weird - more with the older Belle Souers.
After it did that, I mentioned that I did shake the heck out of it - with several shake, sit, shake, sit sessions to get it to be ‘still.’
I may have talked myself into thinking the flavor suffered, but my enthusiasm for the bottle had waned considerable so I did not comment on the taste.
Another bottle from the same vintage we opened last year was completely fine, and I typically like this wine.
It was such a surprise, we took the pics! Perhaps I will email the winery - I figured it was a bit of recurring bad luck, but will ask them.
timely thread. I came home tonight and found some liquid in my basement and a slight vinegar like smell. I tracked it down to a 2002 riesling. The entire cork had blown out of the bottle. There was still some wine left and I looked at the wine and it was a bit cloudy. I gave it a whiff and decided to do the thing that would have given me no pause as a toddler but I knew better as an adult, I took a swig, spritzy. I shook what remained in the bottle and it gave off a fair amount of gas. There was some sediment in the bottom of the bottle that looked very similar to sediment found in Belgian and other similar styled beers, yeast.
Ryan, that does sound like secondary fermentation indeed and there was likely an issue with their sterile filtration which all wines with residual sugar need to have or they will referment in bottle even with high free so2.
I deliberately bottle my whites with around 1000 mg/L of co2 which is around threshold as it allows me to have lower free so2 and also guards freshness.
Just had a bottle of 2009 Sierra Madre Pinot Noir that was really bubbly. Turned into a nice bottle after about an hour in the decanter.
Ok, correct me if I’m wrong, but if the bubbles were caused by incomplete fermentation, wouldn’t you get spent lees in the bottle rather quickly?
As opposed to trapped CO2, which wouldn’t cause any more sediment than normal? Or would the spent yeast be so minimal as to not accumulate in the bottle?
I have seen re-ferment happen in wine that is bottled off dry. Plenty of spritz and no visible lees. I have seen lees in white wine that was not filtered that also had some spritz and that spritz was residual from primary ferm. Hope that helps.