Saturday, December 1, 2012

A Little Chemistry Explains a Lot


I’ve mentioned before that the French Wine Society has great on-demand webinars for members.  I watched one this past week on the subject of wine aromas, and it was fascinating.  The most interesting thing I learned was a very simple fact about wine chemistry which explains a lot about aging and storing wine.

Acid + Alcohol = Esters

Wine contains molecules of acid and alcohol.  I’m no chemist, but basically those molecules are moving around and bumping into each to each other inside the wine bottle.  Eventually, they’ll start hooking up (wine can have that effect) and forming new, larger molecules.  These new molecules are called esters.  (I’ve mentioned them before.)

What Older Wines Have That Younger Ones Don’t

Esters give wine its aroma.  The longer the wine sits in the bottle and ages, the more esters (and aromas) are formed, and the more complex they get.  This is why older wines are so highly prized!  (Keep in mind that not all wines are capable of aging.  Only certain wines will continue to improve for more than a few years.)

Why Vibration Matters During Storage

While the wine is aging, in order for all these esters to be formed, the wine has to be kept still.  When it’s moved around or shaken, those esters fall apart and the complex aromas can be lost.  This is why limiting vibration is important.  So if you’re storing wine for an extended period of time, you need a cooler designed for wine, and not just a refrigerator.  And try to avoid moving the bottles around if you can.

The term bottle shock (there’s even a movie about it) refers to the effect that being jostled and moved around has on the wine.  For example, if a wine is opened immediately after being shipped on an airplane, it will not show its best.  It needs a little time to rest in order for those esters which were broken apart to reform.  And if it’s really shaken up, it may never be quite as good as it was.  This is because some esters are formed after the wine is in the bottle, but others can only form during fermentation.   So if you lose those, you can’t get them back.

It’s nice to learn that older wines have great aromas or that vibration is bad for wine, but I always want to know why those things are true.  I guess I just need to start studying chemistry.

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