To Decant or Not to Decant?
I don't know all of the "whys", but people decant wine for many reasons. Generally I have noted that people think they should decant just about anything if it is "old", but should we really follow that notion?
First we need to really know what "old" means... old is relative to the type of wine, type of grape varietal(s), origin or region it comes from, variability of the vintage year, tannins and style of wine. A wine can be "built" to cellar or built to drink while it is young. For the most part I don't consider a wine old until it is at least 15 years old. When you get to 15 - 20 years or more I would consider most "fine" wines to be fragile so I would be more inclined to NOT decant so that what ever life is left in the bottle will last. The important thing about wine is to know if it is before its peak or at its peak (maybe past its prime and hopefully holding). If is before its peak and a little wake-up call is in order, please, decant by all means!
OK, now that we got the oldies addressed I think it makes a lot of sense to say, by all means, decant the younger wines that have not peaked. In fact, for some of the really fine young wines consider double decanting!
The two most amusing reasons I have seen for decanting wine has been to impress a date or simply to mask a cheap wine. It is way of making a wine seem "extra special". Ahem! Not that I have ever partaken in such an activity but I did decant a 1963 Taylor Reserve Port one time - I had no idea how "chunky" a wine could get. Ok, so maybe I also decanted a bottle of MadDog - I don't quite recall, but, moving right along...
One of the primary purposes for decanting a wine is to mix it up with a little oxygen to ready and wake the wine up (most wine geeks refer to this process as aerating). But, there's more. If you see sediment in your wine you might want to decant it so that you can filter the sediment stuff out. Also, don't forget about that "special" sediment called "cork" - we have all been there; the cork falls apart and there are tons of cork chips floating in the wine ~ nothing like a little extra sediment - decant the wine with a filter.
So, long story short, (legit reasons) decant the "older wines" that have NOT hit their peak to bring out the color, clean up the sediment and lively up the flavours; leave the truly old ones alone (please, be gentle); decant the young'uns when you want to soften the tannins, tame down the oak, filter the sediment and speed up the oxygenation process.
A last and final note to this article on decanting wine... I have heard several times that decanting only applies to red wine. This is actually NOT true. All wines have a lifecycle to some degree and many fine white wines do get better with time. These wines, while not generally known for being long term cellar wines (with a few exceptions) also can benefit from a little aeration. Just do a little digging and find out about what you are serving and make the call.