Knowing how to steam milk will take your coffee skills to the next level. Since it is a key ingredient in lattes, cappuccinos and other specialty coffee drinks, knowing how to steam milk opens up a whole world of different ways to make coffee. Steaming milk requires special equipment—either an espresso machine or a stovetop steamer (see below). It also requires skill; many baristas claim that steaming milk is more challenging than making espresso. However, with a little practice, anybody can master the art and learn how to make great steamed milk in their own home.
What is Steamed Milk?
Steamed milk is made by forcing steam through cold milk. This does two things. First, it gently heats the milk, bringing it into the ideal range of 140°-160° F (60°-70° C). Heating the milk in this way produces a chemical change that sweetens the milk and enhances its flavour (you can read about the science of steaming milk here). Secondly, when done correctly, the steam incorporates tiny air bubbles, giving the milk volume and a smooth, airy texture.
Steamed milk has two components—the actual steamed milk and the milk foam. The steamed milk is milk that is heated to just below the boiling point and has only a small amount of air worked into it. The milk foam is heavily aerated milk that should have the consistency of lightly whipped cream. When milk is first steamed, these two components are blended together, but before long they begin to separate; the steamed milk sinks to the bottom of the vessel and the milk foam rises to the top. These two components are combined with coffee (usually espresso) in different ways to create a variety of specialty coffee drinks.
How Steamed Milk is Made
Steamed milk is made with a steam wand, a thin tube attached to an espresso machine. At the end of the tube is the steam nozzle, a cap that has one or more holes in it. Water is heated in an internal boiler and the build up of pressure forces the steam out of the nozzle. Steaming milk happens in two steps:
- In the first step, the nozzle is held just barely below the surface of the milk. As the steam comes out of the nozzle, it sucks air down into the milk with it. This creates tiny air bubbles called microfoam, which eventually rise to the surface to create the milk foam. The ratio of steamed milk to milk foam can be controlled by how much air is incorporated into the milk.
- Once the desired amount of foam has been achieved, the steam nozzle is pushed further down into the milk so that no more air gets mixed in. The nozzle is positioned in such a way as to create a whirlpool. The whirlpool breaks up any of the larger bubbles and thus creates a finer foam. This position is maintained until the milk reaches the desired temperature.
When milk is steamed properly, it should have the consistency of paint. The foam (when it separates) should be smooth and thick, like soupy whipped cream. It should feel pleasant on the palette (the way milk feels is called the mouth feel ), and have a rich, creamy flavour. Such milk can be used to make latte art, a method baristas use to create intricate designs in their lattes.
How to Steam Milk at Home
To steam milk at home you will need an espresso machine or a stovetop steamer. Exactly how you go about steaming your milk depends to a certain degree on the equipment you are using.
Almost all espresso machines can steam milk, but many consumer machines cannot generate adequate steam pressure. As a result, they cannot produce the same quality of steamed milk as what you get in a cafe. To compensate for this, many home espresso machines come with a panarello steam nozzle. This is a sleeve or tube on the end of the steam wand. The method of steaming with a regular steam wand is different from using a panarello nozzle. Thus it is important to identify if your machine has a panarello tip before proceeding.
1) With an Espresso Machine and a Regular Steam Wand
This is the “proper” method and it is the only way to make really high quality steamed milk. However, the steaming capabilities of different machines vary. With a prosumer machine (and a little practice), you should be able to make steamed milk that will rival any coffee shop. With a lot of practice, you will even be able to create latte art. However, if you have a consumer machine, you may struggle to create cafe quality milk with it. With these machines, the milk foam is often rather fluffy and foamy—quite unlike the desired consistency of soupy whipped cream. Such milk will not have a great mouth feel, nor will it work for latte art. Flavourwise, however, it should taste just as good as any cafe’s.
Regardless of what you are using, as long as your machine has a regular steam wand, the basic techniques are the same.
For full step-by-step instructions, check out the tutorial here (coming soon!).
2) With an Espresso Machine and a Panarello Steam Nozzle
If your espresso machine has a panarello nozzle, as many consumer espresso machines do, the technique is slightly different. Besides compensating for low steam pressure, panarello nozzles are designed to simplify the steaming process and make it easier for home users to make steamed milk. The downside is that they quality of the milk they produce is low. As with many consumer machines, don’t expect a great mouth feel or to be making latte art. There should be nothing wrong with the flavour though.
To learn how to steam milk with a panarello steam nozzle, check out our full tutorial here.
3) With a Stovetop milk steamer
If you are not ready to invest in an espresso machine, stovetop milk steamers are capable of producing excellent steamed milk. As the name implies, they use an external heat source to heat water, which supplies ample amounts of steam. One downside to these devices is that they can take a long time to heat up. Stovetop steamers use a traditional steam wand, thus the steaming technique is the same as with a regular espresso machine.