Espresso + steamed milk = cappuccino

I could stop there, but I might as well tell you that a steak is heated meat. Both statements are true, but there is more to it than that. So, how is a cappuccino made? As the cappuccino "formula" indicates, the beverage starts with espresso. That can be a single shot of about one ounce (30ml), or a double shot of two ounces (60 ml).

The other component of a cappuccino is milk which is steamed using the steam wand of the espresso machine. The heat of the steam and the steam's power to agitate the milk change the structure of the liquid. The fat content of the milk wraps around the proteins and creates what is referred to as microfoam. As the name implies, this is a sort of “tiny foam.” If done properly, you cannot see any bubbles in your cappuccino's foam. The milk increases in volume and takes on a richer, creamier texture and slightly sweeter taste. It pours as a liquid, but with more body than when first poured from the carton.

From that point, all bets are off. What is sold as a cappuccino in the USA can range from a more traditional six ounce beverage made with two ounces of espresso and about two ounces of steamed milk with a topping of dense milk foam to a much larger beverage in a large takaway cup. In Australia, the cappuccino is called a flat white, which is the same six to eight ounce beverage but there is no stiff foam on top, just the espresso and the steamed milk.

Equipment

All it takes is a steaming pitcher and an espresso machine with a steam wand. You should also have a small towel which is wet with water. The size of the pitcher should be large enough to contain the amount of milk you are steaming (during and after the process is completed), but small enough to create a depth of the milk so that the power of the steam does not cavitate the milk nor blow the milk out of the pitcher. A pitcher about of approximately 12 ounces (350ml) is good for one or two cappuccinos*, and a 20-ounce (600ml) size can easily handle two or even three at a time. A “bell” shaped pitcher is best because the shape assists in getting the milk to swirl. That shape also redirects the milk back onto itself and thus helps keep the milk in the pitcher and off your shoes during the process.

The Process

How you go about it depends on a lot of factors, and in particular the design of your espresso machine. Heat exchanger machine or double boiler machines can steam the milk at the same time as the espresso is pouring from the portafilter. Single boiler machine will need to do those tasks separately. Which one first? Create the espresso or steam the milk? For beginners I usually advise pulling the espresso first, then steaming the milk. Why? Good espresso will hold its flavors for a couple of minutes, waiting for the milk, better than the milk will hold its texture waiting for the espresso.

However you attack the two tasks, it is highly recommended that you preheat the cups and pull the espresso shots directly into them. If you pull the espresso into vessel “A” and then transfer it to vessel “B,” flavor, heat, and crema is at least partially lost.

Steaming the Milk

The steaming of the milk is the trick. The basic rule is to do what works. What is that? There is no best way other than what works for you. It depends on many factors such as: The machine's power The design of the tip on the steam wand (how many holes and their size and position) The pitcher's design (shape and size) The amount of milk being steamed The quality of the milk (its age, processing and even what the cows were fed). Even with soy milk, the quality of the product will vary from brand to brand, and even from carton to carton. Even the amount of control the valve for the steam gives you over the flow of steam.

Start with a pitcher filled with the desired amount of cold milk. You might even keep the pitcher in the fridge for a while. Colder milk in a pre-chilled pitcher will increase the amount of time you have for the process which can be very helpful while learning. Let's get started:

1 – Clear the steam wand – Water can build up in the wand and its related plumbing when not in use. If you fail to remove that water and just place the wand in the milk and open the valve, the water blasting out of the wand will shoot milk all over you, the floor, and the machine.

To clear the wand, aim the tip into the drip tray or just fold up a towel and place it on the drip tray. Open the valve and wait for a good, dry steam to issue forth from the wand, then close the valve. Use caution and open the valve slowly at first because the steam and water coming out of the wand can cause very serious burns.

2 – Place the tip of the wand so that it is about midway between the top surface of the milk and the bottom of the pitcher. Slowly open the steam valve. It does not have to be wide open. Most valves will allow enough power with about ¼ to ½ of a turn.

3 – Once the flow of steam into the milk begins, lower the pitcher so that you get an occasional “hissing” as the steam draws in a little air.

How occasional? How much air? Good question. All those variables I mentioned earlier apply, and particularly the quality of the milk. In some cases it is not at all necessary to draw in air. In other situations, if you do not pull in a bit of air all you will get is hot milk. This step, more than any other is where experience and practice become critical.

How long should this adding air process last? You can use a thermometer to know, but using a thermometer gives you one more distraction in a process that happens fast enough that all your attention should be on the process itself and not a thermometer. And besides, you already have a better temperature sensor. While holding the handle of the pitcher in one hand, place the other hand on the side of the pitcher. Stop introducing air when when the outside of the pitcher begins to feel slightly warm to the touch. Just above the temperature of your hand. You do not have to worry about precision here. Just in that general temperature range. As time goes along you will get a better “feel” for what works for you.

4 – At that point, raise the pitcher (so that the tip is deeper into the milk, away from the surface, to stop the introduction of air into the steam's stream and position the pitcher so that the milk is swirling. How to position the pitcher depends on how many holes the steam tip has and the shape of the pitcher. Again, some experimentation will revel the best way to accomplish that.

5 – When to stop the process is the final step. When your on the outside of the pitcher is just beginning to sense that it is becoming a bit uncomfortably warm, that is the time to stop. Shut the steam valve before lowering the pitcher to avoid a milk mess.

6 – As soon as the pitcher is removed from the wand, wipe the wand with the wet towel or wet dishrag to remove any traces of milk, then open the steam valve to create a couple of short blasts of steam to clear the wand's tip of any remaining milk. Again, use care as the steam is capable of causing serious burns.

The Pour

Whether you just pour the milk into the cup, have decided to try latte art, or anything in between, that is up to you. While starting out I would suggest keeping it simple:

While holding the pitcher flat on the counter, move it in small circles. This will help better “homogenize” the liquid microfoam portion of the milk with any stiff foam on top that may have separated.  It there are any large bubbles on the surface of the milk, they can be “popped” by gently knocking the pitcher downward on the counter. Once again, do this gently, and if the counters are fragile use a cutting board or some sort of protective mat for that.

You can create the “traditional” cappuccino by using a spoon just about the spout of the pitcher to hold back the foam and just pour the milk into the espresso. The foam can be poured near the end of the process by lifting the spoon. If you like stiff foam on you cappuccino, add more air at the beginning of the process as discussed in “Step 3” above. How much more air? How stiff do you want the foam and how much of it? Once again, this is all a matter of experience and will come in time.

More information about coffee: * Cappuccinos is the Anglicized form of the plural of cappuccino. In Italian, the proper plural is cappuccini.