Why are the corks of some of my Muscat wines popping out?
We have bottled Muscat wine and with a few bottles (three out of 30) the cork seems to be pushing out.
The storage area is 12 Celsius. The wine was bottled in mid June of this year, by a small winery. This is a very recent event. All the other bottle tops are still that tiny bit concave.
What can be going on ?
Best Answer
This is generally an indication that the wine is not stable - that is, it is still fermenting, which is a defect in wines not intended to be sparkling (carbonated) wines.
If you made the wine, and the winery bottled it, this is your problem. If the winery made and bottled the wine, I would bring it up with them, as it's their problem, and hopefully they will replace the bulging bottles.
In making wines one either has to aim for a dry wine where all the sugars have been consumed and there is nothing more for the yeast to eat, or one "stabilizes" the wine by either filtering out all the yeast or chemically "stunning" them to prevent further fermentation when bottled. Whatever method was supposed to be applied to your wine was evidently not done properly or completely, and now fermentation is continuing in the bottles and causing gas pressure, which is pushing the corks out.
If you can't get the winery to replace the bulging bottles of wine, your best bet is to refrigerate it as cold as possible without freezing it, and drink as soon as possible.
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Quick Answer about "Why are the corks of some of my Muscat wines popping out?"
Corks pop out because of bottling wine too early and it is continuing to ferment in the bottle. As the yeast consumes the sugar still in the wine, it produces both alcohol and carbon dioxide (CO2) gas.Can wine corks pop out on their own?
A cork would start to pop out of the bottle only if the wine or pressure inside the bottle started to expand, and that only happens at temperature extremes of hot or cold, and ones that happen for a spell of time.Why do wine corks expand?
The cork discs on the bottom of a sparkling wine cork are more elastic than the cork granules which make up the rest of the cork, so they absorb the CO2 and expand much more than the granule part, hence the mushroom shape.Can Heat make wine corks pop?
Probably not. If a bottle has been exposed to excessive heat, the wine inside could start to expand, which can push the cork up, and there might also be sticky signs on the neck that wine has leaked out.Should a wine bottle pop?
Most importantly, there should be a pop sound when uncorking, and if the cork comes out too early beware.How 40 Million Cork Wine Stoppers Are Harvested A Day | Big Business
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Answer 2
If you did not bottle yourself, and I don't think you did, Homebrewing may not be able to help a lot other than to give multiple ideas of what is happening. In truth, either @Encerwal is correct and it is still fermenting, or worse, it is simply going bad from contamination and not high enough alcohol content to stop the pathogens are the two things that quickly come to mind for me.
In either case, I would try to contact the winery. If the bottles have not been exposed to high temperatures, this should not be happening. If the wine was intended to be sparkling, it should be bottled with correct higher strength bottles and the correct, wired in corks to handle the added pressure. Even it the wine is still good, not a pathogen issue, you are in danger of pressure bursts, and a major mess on your hands.
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