Q. What are legs?
A. Wine legs are residual wine that sticks to the side of a glass and runs down it. It's caused by changes in surface tension due to the differing evaporation rates of alcohol and water.
The Spanish call them tears; the Germans call them church windows. There's a lot of interest in them but they really tell you very little about the wine's quality. They do provide a clue about a wine's alcohol content level. Heavier legs indicate a higher alcohol content level, which is neither good nor bad.
Today, wineries are asking growers to let the grapes hang on the vine longer. This makes the sugar level in the grapes rise. Yeast eats sugar, so higher sugar levels in the grapes means the wine will have a higher alcohol content level.
Winemakers are required by law to list the percentage of alcohol in each bottle on its front label. If you see it listed on the back, that's because they are legally treating the back label as the front.
Q. Are there rules of etiquette for receiving a bottle of wine in a restaurant?
A. The waiter will show you the wine bottle, open it, and place the cork on the table in front of you. You don't need to do anything with the cork.
The custom of placing the cork on the table started in the 1800s when restaurants were known for uncorking expensive bottles of wine, selling it, and putting less expensive wine in the bottle. This prompted wineries to brand their corks. Waiters began putting the cork in front to the customer so they could check to make sure the brand on the cork matched that of the wine label.
A cork that smells musty is an indication of a natural compound called TCA (trichloroanisole); if TCA levels are high enough to be detected, the wine is described as corked ― it's no longer good. You can't usually smell corkiness on the cork in a restaurant. Also, white crystals (tartrates) on the cork are not necessarily bad and a dried out cork doesn't always mean the wine has gone bad.
Next, the waiter will pour a small amount of wine in a glass and expect you to see if it's sound. (You are not tasting the wine to see if you like its flavor.) If a wine is corked or prematurely oxidized, those are reasons to send it back.
Steps to see if wine is sound:
1. Swirl the wine.
2. Smell it, and don't be shy. You need to stick your nose far into the glass. Wine that is tainted with TCA (also known as corked) will smell musty, murky, or like a wet dog. If a wine has been prematurely oxidized it may smell like aged sherry.
3. It is customary to taste the wine but you really don't need to taste it to tell if it's sound.
Q. How has technology influenced winemaking?
A. We are unimaginably lucky these days because winemakers know so much about making wine. They rarely make bad wine anymore. There's more interesting wine and so-so wine but there's a heck of a lot of good wine out there. It's harder to go wrong now than it ever was before. It's a good time to be drinking wine.