Awww hell yeah this thread is 100% my jam. I'm a huge coffee nerd, love me some wacky coffees. It's part of living in Melbourne, Australia, I guess.
Anyone know the trick to making good cappuccino foam? Watching online videos doesn't help. At first I thought it was because I was using 1% milk, so I went up to 2% and still seemed no good. Do I need to use whole milk? Cream?
Do I just have terrible technique?
When using non-whole milk - frothing milk relies on protein and fat content. The less casein that is present in the milk, the poorer quality the frothed milk will come out as heated casein stabilises the air bubbles introduced by steaming. Most typical full cream or skim milk has enough protein content to stabilise the milk foam. Some "barista quality" milk is sold with added casein to improve the texture of the milk when it is heated.
As to fat content -
Fat content in milk also can cause impacts to frothing quality. Above 40C heat (usually you want to aim to get milk to about 60-65C) the lipids in milk melt. It's thought that the fat content helps act as a barrier between the stabilised protein-air bubbles and the milk liquid itself; otherwise you'd end up with coalesced milk bubbles (and therefore, no foam).
If you're learning how to froth milk for the first time, it is probably easiest to start with high fat content milk like full cream milk, or skim milk. 1-2% fat content milk will probably foam somewhat, assuming it has normal protein quantity, but the mouthfeel will be worse due to the fat content not preventing bubbles in the foam from coalescing.
Let's talk about technique. Using a typical steam wand, there is something of an art to foaming milk properly.
Like Nenjin said - start low in the milk jug and slowly work your way up into the top of the milk. Don't contact the bottom of the milk jug - this doesn't do much for the milk and might just scorch the milk surrounding the contact point rather than making steam bubbles.
Lattes have less foam than a cappucino, so you don't want to send your wand as far down to the bottom. The more volume of milk that is exposed to the steam wand, the more foam will be produced.
A good ratio to keep in mind is that a cappucino is roughly 30:40:30 espresso:heated milk:milk foam, while lattes (at least, not american lattes) are more like 30:55:15 espresso:heated milk:milk foam.
I have tonnes of coffee equipment, love making all sorts of stuff. Had a shot at making nitro cold brew a few months back, but it stalled as my shitty housemate stole my nitrous canisters to huff instead. That's another story.