Making cappuccino foam is a skill that takes practice. But you can most likely learn how to do it well enough at the end of your first day if you have an experienced barista around to instruct you.
What you need:
- Cold Whole Milk, ideally. 2% will work, as will soy milk. Skim milk does not work very well (But why bother with skim milk anyway? — A cappuccino is mostly air!)
- A cappuccino machine with a milk steaming wand (the longer the better)
- A metal container with a handle (so you don’t burn your hand)
- A cooking thermometer (optional)
- A spoon for foam / milk separation.
1. Fill a metal container about halfway with cold milk.
Be careful to place the wand well into the milk before turning it on so you don’t spray milk all over yourself. Also, it is important that the milk be cold not only for health reasons, but also so that you have plenty of time to develop a thick foam over the milk as it heats up.
2. Turn on the steamer. It will make a high-pitched “screaming” sound at first, which will change as the temperature of the milk changes.
3. Move the steamer up to just under the top of the milk so that the steam creates tiny bubbles (foam) out of the milk. You will have to experiment with exactly how far into the milk you have to keep the wand to make sufficiently thick foam. As a rule, thicker foam is better.
If the steaming wand is too close to the surface of the milk, it will either “spit” milk all over you or your foam will be too thin.
4. Heat the milk to a range of 135 degrees F (57 C) to 145 F (62 C). You may need a cooking thermometer to measure the milk’s temperature, so it’s not too cold (yuck) or too hot (burning the milk or the person drinking it). With enough practice, you will be able to gauge by the sound the steamer makes in the milk that it is hot enough. Also, when you get a feel for how fast the milk heats up in relation to how fast foam is created, you will be able to do both in perfect balance — heat the milk and create foam — so both parts of the process conclude simultaneously.
5. Pouring the steamed milk requires some practice as well. This is not (in my opinion) an exact science, but as a general rule: Cappuccinos should be about 70% foam (as opposed to lattes should be about 70% milk). You will have to use a pouring spoon to hold back the foam at first so that enough milk lands in the mug (you would pour it into a fresh shot of espresso). Then, when you’ve filled up your mug with about 30% milk, top off the rest with foam. The foam should be thick enough to last at least 10-15 minutes before it deflates, but this will happen in any case if its not consumed by your happy customer in a timely manner.