From the mailbag, a listener asks: Why do we age wine in wooden barrels?
Good question! These days, aging wine inside big wooden barrels seems pretty inefficient, if not downright old-fashioned! But winemakers have good reasons to prefer oak barrels over cheaper alternatives!
When newly-made wine is put into barrels, it isn't finished yet. Most wine is left in barrels to age for six to eighteen months, depending on the type of wine. During that time, the wine undergoes various chemical changes that make it taste better.
But most of these chemical changes can't happen without exposure to airand that's why winemakers prefer wooden barrels. Stainless steel or plastic containers would cost less and last longer, but they're airtight. They're fine for storing wine, but the wine doesn't age properly in an airtight containerand it definitely doesn't taste the same!
Inside The Wine Barrels
Most wine barrels are made of oak. That's because oak is dense wood with a very "tight" grain. It's a great compromise - oak wine barrels are tight, but not completely airtight, so wine can age properly without leaking out.
As wine ages in a barrel, it absorbs some of the wood's chemical compounds, and winemakers have found that the flavor of oak "tastes" better in wine than other hardwoods. That's partly because oak contains tannins, the same compounds that make wine taste "dry," or astringent. In fact, some wines are even described as "oaky."
So, most winemakers prefer oak barrels despite the expenseand, although some big winemakers do use steel or plastic for storage, they still blend the wine with barrel-aged wine for the taste of oak!