The Right Size

• The 20-ounce behemoths available at your local corporate coffee shop have skewed the public perception of what a proper cappuccino looks like. A purist's cappuccino is much, much smaller -- usually served in a cup with a capacity of about 5 ounces. The beverage comprises approximately 1 ounce of espresso and 1 ounce of milk. The foaming adds volume to that milk, filling out the cup. Because the balance of milk and coffee is so essential to the drink -- and because a strong, velvety foam is the key element in a cappuccino that keeps its proper volume -- the key to a perfect cappuccino is proper milk preparation.

The Art of Foam

• Start with cold milk, filling your metal steaming pitcher by no more than one-third. Run the steaming wand for a couple of seconds until any water has been cleared. Turn it off. Angling the pitcher, touch the tip of the wand into the surface of the milk and turn it on. Keep the wand in place in the milk: in other words, no "swirling." As the wand introduces steam into the milk, the foam will begin to rise. As it does, lower the pitcher, keeping pace with the rising volume. Work like this until the milk has doubled in volume and the temperature of the milk reaches 65 degrees Fahrenheit.

Finishing Strong

• When the milk is properly warmed, rap the bottom of the pitcher firmly on a flat surface. This compresses the foam, keeping it from developing large bubbles that pop and "deflate" a properly-proportioned cappuccino. Prepare your espresso in your cup of choice and then delicately pour the foamed milk directly into the center. The correct proportion is one-part espresso, one-part steamed milk and one-part foam.

Cappuccino "Training Wheels"

• As it's difficult to see the proper proportions of coffee, foam and milk in an opaque glass, new baristas might try using a clear one. After a few successes, the correct amounts will be easier to determine from sense memory.