Years ago, one of my key restaurant customers called in a panic during their lunch service. A customer had ordered the most expensive wine on the list, said it was faulty, and wanted to send it back. Unfortunately for the restaurant, nobody (including the customer) had ever tried the wine before. The wine in question, Champagne Krug Clos du Mesnil, currently fetches around NT$$35-40,000 a bottle in the few places it is available. Unfortunately for the customer, there was nothing wrong with the wine. Made from a single vineyard of chardonnay grapevines dating from 1698 and surrounded by stone walls, it is also aged for 10 years in bottle before release, making it not only very pricey but also very distinctive.
So how do you know if your wine is faulty, and what can you do about it? There are a couple of common faults you can look out for:
1. Oxidisation--This happens when the wine has been exposed to oxygen, much like a banana turning brown. As soon as the cork is out, this process begins and the wine will lose fresh fruit character, take on a sour nutty character and eventually turn brown and sometimes cloudy. This happens even more quickly with wines that haven't been exposed to oxygen for a long time. A 1959 Beaujolais I once tried oxidized in my glass between my first and second mouthfuls. So when the waiter says, "It's only been open for three days" do what I do and order a beer.
2. Cork Taint--About 3% of natural corks (versus plastic or screw caps) impart a musty, wet-dog smell to the wine. This is natural and you are fully entitled to send it back. Your restaurant or retail store will get credit for this from their supplier (if they know what they're doing). This is why we taste wine when we order it at a restaurant, not to see if we like it or not.
3. Another common fault to look out for is a nail polish remover type of smell that definitely shouldn't be there and is the result of what we call volatile acidity.
4. Don't be concerned by small tartrate crystals forming on the bottom of the cork or bottle, or some sediment at the bottom of the bottle.