Does unopened champagne expire, or does it get better with age? My sister gave me a pretty good quality bottle of champagne a few years ago, and I want to know if it will be any good before I open it and serve it to guests.
It may be OK if it has been stored well, but there’s a good chance that it isn’t very good anymore. I would have a second, new bottle on hand if I were serving it to guests.
Generally speaking*, it’s only the robust reds that improve with age (things like a cabernet sauvignon). Your champagne might still be good, but it might have gone funky. Gus is right – a backup would be a good idea.
*(way oversimplifying)
Interesting question, when you say it may not be good, does that refer to taste or could it cause illness?
As long as it was sealed, it’s a question of how it tastes.
Well, crap. I’ve been saving a good bottle of French champagne for a “special” occasion for the past two years. I hope it’s still good. It’s been stored chilled the whole time, does that help?
If it is truly “good” champagne, 2 years chilled shouldn’t have killed it. Much. It really depends on what you mean by chilled. Two years in a properly controlled wine cellar, or two years in the back of the fridge. The latter would not bode well for the wine. But most white wines aren’t keepers.
Markxxx, if I wanted to serve a bottle of good champagne to my guests and it was foul-tasting, I know it would make me sick. 
It should be stored in cellar conditions to last. 55 degrees Fahrenheit, minimal light, and tilted so the cork doesn’t dry out.
It can expire in the sense it may start to taste flat, cardboardy and stale, but it won’t poison you. No known pathogens can survive in fermented beverages. The Worst Case Scenario would be storing it somewhere hot (like a boiler room) so the yeast have a chance to die and decompose, giving it a rotten meat smell.
My BIL is a winemaker and told me that 90% of all wine sold in the US is meant to be drunk the day you bring it home from the liquor store. Letting it age won’t do anything for the wine, as it is to designed to be consumed the moment it is sold.
Another 5-7% of wine will benefit from aging, because it was made for that. Those bottles should be stored properly (on their sides if they use corks, upright is fine if they have screw caps) and in temperature controlled environment. You won’t find wines for sale under $25 that fall into this category. Not sure about champagne, but again, if you spent less than $30 I suspect it was meant to be drunk right away.
The remaining bottles are meant to be consumed on the way home from the liquor store.
I think it really depends on the Champagne.
And it won’t expire to the point that it will make you sick, it just might not have the brightness/acidity/etc. that it would have had, and could potentially have nuttier/yeastier characteristics. So really, your personal preferences would be the deciding factor on whether it’s drinkable or not. I personally like a bready/yeasty character in my Champagnes, at least the better ones.
I really hate to use price point as a deciding factor, but it does seem to be one that most people can relate to. For me, personally, if the wine was less than 50 bucks, it probably won’t benefit much from anything more than a year or two of bottle age. But that doesn’t mean it will be bad, it just means it won’t get any better in that time. And of course there are exceptions aplenty.
More specifically, if it’s a relatively inexpensive non-vintage Champagne, to me it’s a drink now wine, to be consumed within a year.
If it’s a vintage Champagne, it might depend on the style. A recently released wine would definitely benefit from a couple of years of bottle age, I think we’re just seeing the 2002-2004 vintages hit the shelves right about now.
However, a recently released late disgorged wine would probably be best if consumed within a year or so, since it’s already benefited from years of aging on the lees, which gives those wines that really yeasty character that I absolutely adore. It’s mostly 1996-1999 vintages of those types of wines currently hitting the market.
The only way you’ll know for sure though obviously, is to open it up and taste it. 
Am I the only person around who vastly prefers cheap Spanish cava to even upmarket French champagne? (yes, I do realise that ALL true “champagne” is French).
Most cava, even very inexpensive brands, is so drinkable and refreshing, where most of the good champagne I have had seems to have a distinctive aftertaste that is somewhat of a turn off…
They gave top marks to 180 year old champagne salvaged from a shipwreck - that’s all I need to know on the subject 
Hmmm, well, it’s been stored on its side in the back of the fridge. It’s not super expensive, I don’t think - it’s Michel Loriot Champagne Brut Réserve Blanc de Noirs.
[QUOTE=Surly Chick;13259455Michel Loriot Champagne Brut Réserve Blanc de Noirs.[/QUOTE]
This is a non-vintage Champagne but will improve a bit with some aging (although many vintage – i.e., dated – Champagnes will age much better).
This is not an expensive bottle, under $20, so there is no reason to save it for a special occasion but would probably taste great with a seafood dinner some evening “just because.”
I’ve had it several times and it is a creamy, nutty offering but not exceptional with a hint of clean stonefruit.
I say drink it!