We're not going to go too much into the technique of steaming milk and the types of milk drinks ... these pages are meant to be about espresso in it's pure form, not about milk! Also, your espresso machines manual is going to have more relevant, specific information than I can offer. And I really don't know much about milk, I know about coffee, so that when people tell me they make great skim-milk Latte or use soy milk, I don't know what to say. In the old days, we were taught that you needed to use whole milk, not even low fat, because it was the fats in the milk that interact so well with the coffee. There is a unique nutty taste that comes with the fat-espresso interaction, but a key to steamed milk is the sweetening of lactose when it is heated by this technique.
To get that true sweetening effect you have to avoid pumping the milk full of water while steaming, and scalding the milk. The former is a problem when the machine has run out of steam, and will just gurgle hot water into the milk. Scalding is easy on big commercial machines that have a separate tank for the steam, but is difficult on a home machine that has a limited amount of steam pressure to offer. You have to get up to the Pasquini price range to get a home machine that has a separate tank for steam. Otherwise, home machines have to toggle between a low-pressure espresso-making setting and a high-pressure steam setting. This means there's going to be a delay between making espresso and steaming. You either have make espresso first, switch to steam mode, and wait for the machine to get up to steam pressure. Or you steam milk first, then switch to espresso mode and follow the manuals instructions to release pressure/heat to you can then brew the espresso. Neither case is ideal, but I would make the espresso first then steam the milk. Why? Because having made drinks in espresso bars for years, I think pouring the milk right after steaming, what we called "wet foam" (meaning that it hasn't sat and separated into hot milk capped with dry, stiff foam), benefits the beverage quality more. If you have to scoop out the foam with a spoon, then you have "dry foam". That said, I do not claim to be a great Barrista, and I don't know what the "official" techniques are, nor do I care to make rosette designs in my latte or what not... I just am speaking from my experience.
Fake Foam: As an aside, frothing milk in one of these French-press type "milk frothers" may work well for you, but you are not going to be getting steamed milk by this technique, in particular the sweetened lactose flavor. You get foam, but not the right flavor. I would really try to learn to steam milk on the machine. We don't sell them for this reason, but you can get them almost anywhere.
Primary Espresso-Based Milk Drinks
|Served in a demitasse cup, this is an espresso with a "stain" of steamed milk on top, a very slight amount of milk. At most, there is 1 ounce of milk on a 2 oz. double espresso.
||Served in a cappuccino cup, which is 5.5 to 6 ounces. I was taught that a true cappuccino, once it sat and separated, would be 1/3 espresso, 1/3 milk, 1/3 foam. But you pour the foam on top of the espresso just after steaming when it is wet. So this means the total volume of a single cappuccino could be less than 4 ounces, and a double would be 6 ounces. This is a small drink!
||This is traditionally a "breakfast coffee" in Europe, where it exists at all. With a Latte the ratio of espresso to hot milk tends to be 1:3, 1 part espresso to 3 parts milk. In reality, I think we see 1:4 and 1:5 in many coffeehouses. In some techniques the espresso and milk are added simultaneously or the espresso is added to the milk. More so now the modern barista adds the milk to the already pulled shot, and even makes designs in the way the espresso interacts with the milk.
Basic Steam Techniques
Read Your Manual: The manual that comes with your espresso machine will go into detail about this ... at least it better! So many espresso machine buyers are interested in good steamed milk that most machines include a auto-frothing device, or a nozzle that takes in air to alleviate the need for mastering the correct technique used on commercial machines. Actually, many of these gadgets work very well, and unlike the crema-enhancing devices for espresso, they do produce good steamed milk with the correct flavor! Some (like Pavoni) actually suck up the milk from a secondary container, and others simply have an aerating pinhole and allow more through-flow of air into the milk. On almost every machine, they come off readily and you can steam without their aid.
The most important note I can add to your machines instructions is this: the machine must be up to full steam temperature, and you always need to open up the steam wand and clear out water into a standby vessel or a cloth until you get a flow of pure steam. If you don't do this, you will immediately shoot a bunch of water into your milk, which really affect the flavor and the ability of it to steam up well.
We did have an employee named Cameron who was an expert barista and cafe manager and so we filmed this video of her steaming milk. Check it out