Frothing Milk for Cappuccino & Steaming it for Latte
Frothing Milk for Cappuccino & Steaming it for Latte
Cappuccino and latte are espresso drinks made by mixing the espresso with frothed milk, and with steamed milk, respectively. All espresso machines will have a steam wand (usually on the side, adjacent to the portafilter) that is used for frothing and steaming milk. For cappuccino, the milk is frothed into a "microfoam" that is nearly double the volume of the original milk. For latte, the milk is "steamed." The result of steaming is simply hot milk (with a little bit of foam).
You will need a stainless steel frothing pitcher in which to froth the milk. Frothing pitchers come in many sizes; choose the size in accordance with how much milk you are frothing. In a coffee shop, you should have a variety of pitcher sizes so that you can choose the right one for the job. While you should not start with the pitcher more than 1/3 full (to allow for the foam to double in volume), you should also not have much less than this in the pitcher either, or you will have more difficulty in getting the milk to foam.
If you are making microfoam for cappuccino, you should only fill the frothing pitcher 1/3 of the way with milk, since the milk will double in volume during the frothing process. It is also best to have a quick-read thermometer with a clip attached to the side of your frothing pitcher. This is because the milk should not get too hot. (The flavor of the milk will be altered if it is heated beyond 160 degrees Fahrenheit.) There are special milk frothing thermometers than can be used for this, but any kitchen "quick read" thermometer will work.
"Frothing" is the process of creating "microbubbles" in the milk. This is done by blowing hot air (or steam) through the milk. Since the bubble surface is actually a well-knit string of protein molecules, skim milk will produce a more lavish froth than whole milk. In fact, it may be hard to get whole milk to froth at all, although whole milk will have a creamier taste. Partially skimmed milk (2%) is recommended. It is easy to froth, and it will have a creamy taste. It is the most difficult to get soy milk to froth, although it can be done.
Again, to froth the milk, fill the frothing pitcher no more than 1/3 of the way with cold milk. Ideally, the frothing pitcher should be at the same temperature as the milk, and both should be as cold as possible. To prepare the espresso machine for frothing, first open the steam wand to purge any water that had condensed in the tip, then close it again. (If you don't have a drip tray on your espresso machine, purge the steam wand into an empty cup.) Then place the tip of the steam wand into the milk so that the tip is about ½ inch below the surface of the milk.
Then open the steam valve all the way at first, and make sure the tip of the wand is kept near the surface of the milk, because it needs to draw air from the milk's surface in order to produce the froth. For frothing, you will need to experiment, but a good starting point is to try to keep the tip about ½ inch below the surface of the milk. For steaming, you can completely submerge the tip.
If the tip is too near to the surface of the milk, it will create bubbles that are too large. Remember that we want "microbubbles." On the other hand, if the tip is too far below the surface of the milk, it will not draw enough air to create froth (which is what we want for steamed milk). You will have to experiment to learn what is appropriate, and remember that as the froth rises, the surface of the milk falls, so you will have to adjust accordingly during the frothing process.
It is also good to swirl the pitcher in a clockwise (or counterclockwise - whichever is more natural for you) motion to create a "whirlpool" motion in the milk. This will cause the froth to be mixed evenly throughout the milk so as to create an even texture.
In fact, you will learn that if you hold the pitcher correctly, you will not need to swirl the pitcher. Instead, the steam pressure itself will make the "whirlpool." To create a natural whirlpool, hold the pitcher level, but keep the (slightly slanted) steam wand near the side of the pitcher. Allowing a natural whirlpool to form is better than manually swirling the pitcher, because you will have better control of the tip-depth when you are holding the pitcher still.
