First things first - getting the wine into your glass. In most tasting rooms, you will receive a one ounce pour, with some wineries being more generous than others, but that’s the least you should expect. If you are creating your own tasting experience, just keep the amount at about 1/3 of the glass.
Hold the glass comfortably by the stem, close to the bowl, raising it against the lightest possible background available and tilt it at a 45 degree angle. This allows you to inspect the color and clarity of the wine. The wine should be immaculately clear and free of any debris (a little cork now and then is going to be inevitable). Cloudy wine is usually indicative of a wine that old, spoiled or improperly filtered, but taste it anyway, because you will be able to tell very quickly whether it’s a concern or not. A wine’s color will indicate its maturity and whether or not it has been barrel aged.
Some wines benefit from barrel aging, and white wines will take on a yellowish cast if stored in a barrel before bottling. Basically, white wines will deepen in color as they age, going from a pale, almost clear color to a lighter yellowish-green that will eventually turn goldish-brown over time. Red wines will actually fade in color through the years, losing their initial blue and purple jewel tones, settling into tawny and burgundy shades of brown as they mature. Slow oxidation is at fault here, and red wines especially will show this as the pigments in the wine fall out of solution and slowly drift to the bottom or side of the bottle, depending on how it was stored. Storing wine on its side, in a cool and dark environment is considered to be the proper way to cellar, keeping the interior of the cork wet and supple, which reduces cork shrinkage and taint, minimizing the amount of oxidation over the years.