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.

Keep frothing until you have made the texture that bests suits your tastes. Generally, the milk should be frothed until it has doubled in volume. Once the milk has reached this point, move the tip of the wand slowly down into the milk. This distributes the froth into the milk and ensures an even temperature. When the thermometer reads just over 150F, turn off the steam tap and remove the tip from the milk.

The frothed milk will have a temperature of 158-162F because the thermometer takes some time to reach the actual temperature, hence the need to stop the frothing process when the thermometer reads 150F. Milk frothing thermometers have a colored band around 140-160F. If using one of these thermometers, stop the frothing process when the temperature enters this colored band.

If the bubbles at the surface are larger than you would like, you can break them down into smaller bubbles by banging the frothing pitcher onto a working surface, or by stirring the milk, or by gently swirling the milk in the frothing pitcher. Again, we do not want large bubbles. We want "microfoam" with tiny bubbles of uniform size. When the milk has doubled in volume, and is in the 150-160F temperature range, it is ready for use in cappuccino.

For latte, we do not want a think microfoam as the end result. Instead, we want heated milk (between 150-160F) with only a small head of foam. So when using the steam wand to heat milk for latte, you should submerge the tip more deeply into the milk so that few bubbles will be produced. You can start with more milk in the frothing pitcher (up to 2/3 full) when heating it for latte, since you will not expand its volume much; you will only get a small "head" of foam.

When pouring the heated milk into a latte, the milk runs in first (leaving most of the head of foam in the frothing pitcher) because the milk is heavier than the foam. Traditionally in a latte, the espresso and the milk are poured into the serving cup simultaneously. After the espresso and the hot milk have been poured together, all that will remain in the frothing pitcher is the head of microfoam.

To finish a latte, the foam is poured over the mixture. Professional baristas move the frothing pitcher in various ways while pouring the microfoam to create pretty patterns on the surface of the latte - hearts, flowers, leaves, etc. This is not as hard to do as it looks. You can experiment, and teach yourself to make some of these patterns too.

Tips for Professionals - Temperature

Temperature is very important at both "ends" of the process. The colder the milk and the pitcher are before you start, the better the end result will be. It is also best to always use a frothing thermometer to take the guesswork out of it. The ending temperature of the froth can have a significant effect on the flavor of the finished drink.

If the frothed (or steamed) milk is cooler than 150 degrees, it will still maintain a strong "milk" flavor that will tend to dominate the flavor of the drink. Going above 150 degrees allows the espresso flavor to dominate. But if you allow the milk to get hotter than 160 degrees, you will lose almost all of the milk flavor, and any bitter elements in the espresso will dominate the drink.

Remember that customers who want cappuccino or latte usually do not want any harsh or bitter undertones to surface. If your espresso is perfect, this will not be a problem, although you still want some of the milk taste as a "backdrop" for the espresso flavor. Above 175 degrees and the milk is burned. Do not use it. It will taste bad.

Tips for Professionals - Maintaining the Steam Wands

Immediately on finishing the frothing process, set the pitcher down, and take a few seconds to clean up the steam wand. If you stopped frothing in the low 140 degree range, the temperature of the milk will continue to rise into the ideal 150-160 degree range while you clean the wand.

First, open the steam valve briefly to purge the wand again. Sometimes, some of the milk will have remained in the wand. If it sits there it will scorch on. Not only will this impact the flavor of subsequent batches of milk, but it will obstruct the wand and interfere with the frothing process. This effect can be minimized by purging the wand after each use. (This is also why we remove the tips and clean them after closing each day.)

While the wand is still hot, take a damp cleaning cloth and wipe them down so that a milk film doesn't accumulate. The cleaning cloth that you use for this should be only be used for this one purpose. We would not want to wipe down a dirty counter and then use the same cloth on the steam wands. Anything that will eventually touch something that will go into a drink (in this case, a steam wand) should have an exclusive cleaning cloth. In a shop, you might want to have different colors of cleaning cloths, and make sure that your staff knows which color is to be used for what.

Tips for Professionals - Pouring Different Drinks and Using a Spatula

If you are frothing milk to be used for both cappuccino and latte, you can froth the top portion of a pitcher, and leave some of the milk simply heated in the bottom of the pitcher. Pour the top portion (the froth) into the cappuccino first, but don't finish off the cappuccino yet. Then pour the bottom portion into the latte, while holding back whatever froth is still floating in the pitcher with a small spatula. (A small pastry spatula works nicely for this.)

Return to the cappuccino, and push most (both not all) of the remaining froth out of the pitcher and into the cappuccino using your spatula. This finishes your cappuccino (almost). Return to the latte, and pull out a nice "dollop" of thick foam to top off the latte, again using your spatula. Try to make this as round as possible, and drop it into the center of the latte. It will spread into a circle as it sits for a few seconds.

If you have pastry stencils available, you can decorate your cappuccino by using a stencil and some cocoa or cinnamon powder and a pastry shaker. Remember that this is just for show. Do not use so much so as to impart a heavy cinnamon or chocolate taste to the drink unless the customer knows that you are going to do this. The nice circle of foam in the latte can be used to make latte art.

Tips for Professionals - Latte Art

One important aspect of any barista competition is the artistic presentation of a latte. In this phase, the barista creates their own "signature patterns" on the surface of the latte using the last dollop of microfoam as the starting medium. This is done by dragging a sharp tip through the microfoam to redistribute it on the surface. Many baristas use the tip of the frothing thermometer as the main tool to create latte art.

It is quite easy to learn to do symmetric shapes like hearts and stars. A beginner can master this in just a few attempts. This is well worth it. It just takes a second or two, and will "wow" many of your customers, and put you (in their minds) a step above your competition.

In professional competitions, the designs can become extremely elaborate, and can incorporate syrups for a wider spectrum of colors and tones in the design. Some of these patterns can take months to master, and minutes to perform. You do not need to do this in your coffee shop. But if you are considering competition, you should obtain some books or videos that show examples of different kinds of patterns and how they are done.