Instructions

1. Evaluate the bottle. Wine kept in temperature-controlled conditions lasts longer and consequently has a higher value. If your bottle has been baking in the sun, the value has certainly been lowered. Look for other signs of physical stress, like a loose cork or a discoloring of the wine. Bad white wine usually takes on a yellow-green color. It's harder to tell with reds, but look for a purplish-brown hue. A musty or corky smelling wine is also a bad sign.

2. Consider the wine's history. If you have been the only owner, the bottle has probably retained its value. In white wines, vintages older than 5 to 7 years lose value quickly. For example, a bottle of 1998 Chardonnay would not have much value (or much taste) in 2007. Reds tend to follow a bell curve, not having as much initial value but growing with age (assuming they are unopened), then peaking at a certain time before heading downward in worth. Unfortunately, it is different with every bottle. This is also true of champagnes and dessert wines.

3. Ask the experts. Wine is rated on a 100-point scale. It is rare for a wine to be scored below 50, and most grocery store wines fall somewhere between 65 and 87. The best bottles score above 85 points. Most connoisseurs consider anything over 90 to be of high value. Robert Parker, Stephen Tanzer, Clive Coates and the Wine Spectator magazine are all high-profile, well-respected critics of wine. Most people consider their ratings to be accurate and helpful in determining value. All of theses critics have magazines and websites to which you can subscribe.

4. Attend an auction. Luckily, there are plenty of online wine auctions, and you can determine the value of wine while in your pajamas. Two reputable online auction sites are wine-searcher.com and winebid.com. Both allow you to search their database by bottle and see current prices.

5. Know that the majority of wines age very quickly and retain little value. Unless you are a connoisseur or serious collector, your collection is probably not full of high-value wine. There are always surprises though, so keep an eye on the popularity of each and every bottle.