Why Do Champagne Corks Expand After the Bottle is Opened?

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Why do champagne corks expand after opening the bottle?Kyle Kurani:It all depends on how long the cork has been in the bottle. Champagne starts its life with a crown cap (a beer bottle top) with a little yeast and sugar inside to make it bubbly. After staying under that cap for at least 15 months (the law in champagne), it then gets disgorged and the cork that we see gets put inside, then shipped over to us. That cork is just one big cylinder, uniformly shaped; they all start out looking like the one below. Since most champagne is consumed relatively quickly, the cork doesn’t have time to compress; it wants to go back to the size it was when it was forced in.

If you ever open an older bottle of champagne—I have had some that has been “on the cork” for 30-plus years—the cork comes out shaped like a mushroom and does not expand at all. It has had plenty of time to get compressed and hold that shape. Even one or two years on the cork will make a noticeable difference in how much it can spring back or not.

As a side note, aging your non-vintage champagne for one year makes a huge difference in how the wine tastes. If you can afford to tuck a case in your closet for a year and start replacing the old ones with new bottles when you drink them, you will be greatly rewarded!

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