To know if you’ve foamed the milk correctly, look for a thick, glossy foam that will slowly dissolve when stirred with a spoon.
The foam should be light and airy, not gritty or bubbly. A beautiful sheen on the surface of your foam, almost like gloss paint, indicates you are getting good results.
If it’s too thin and watery it means, there is not enough air in the mix – try again!