Perhaps you've seen people go through the ritual of swirling, sniffing, and swishing wines around in their mouths when tasting wine. This is because wine tasting involves more than just our taste buds; that is, wine tasting is a sensory evaluation of wines. More specifically, proper wine tasting involves three phases: (1) appearance, (2) aroma, and (3) taste.
The process of tasting wine begins by assessing its visual appearance; more specifically, its clarity and color. Accordingly, you'll need to pour wine (no more than 1/3 of a glass) into a clear wine glass and hold it by its stem in front of a white background (e.g., tablecloth or napkin). This may feel awkward, but it prevents the heat of your hands from altering the temperature of the wine and your fingerprints from changing the wine's appearance. Wine should appear clear and brilliant versus cloudy and dull. Slightly tipping the glass may give you a better view.
The color of wine varies greatly depending on its maturity, and more color usually indicates more flavor and age. Whereas time improves many red wines, it ruins most white wines. Colors of white wines range from green to yellow to brown. Red wines begin purplish in color, become lighter, and then change to a brown color as they mature.
Swirling is the final step in assessing the wine's appearance. This process allows you to visually observe the body of the wine and releases the wine's bouquet (phase 2). After you have swirled the wine, notice the legs (also known as tears) that form on the inside of the glass and stream down. 'Good legs' (a high number) may indicate a thicker body and a higher alcohol content and/or sweetness level.
Once you have successfully swirled the wine, place your nose into the glass and inhale deeply to draw its bouquet deep into the nose. The smell of the wine is extremely important to its overall taste. This is because your taste buds can only detect four distinct tastes (sweet, salty, sour, and bitter), whereas the nose can detect thousands of aromas that give us a vast number of flavors. Think about the scents you are inhaling and try to identify them. What do they remind you of? It is likely that you will smell different scents than others around you. Perhaps you will not be able to distinguish various scents initially, but rest assured that scents will become more identifable with time and practice.
Now that you have examined the wine using your eyes and nose, you are ready to taste the wine with your mouth. Take a decent sized sip of the wine and swish it around in your mouth for 15-30 seconds before swallowing. Notice the initial taste of the wine as you take it in. Think about the wine's body. Also notice the taste characteristics of the wine as you swish it around in your mouth, keeping in mind the four basic components of wine: (1) acidity, (2) alcohol, (3) sweetness, and (4) tannin. Swallow the wine and notice its aftertaste. When the aftertaste is gone, reflect and articulate your impressions of the wine.