The size follows the coffee
The size follows the coffee. An espresso is three centilitres, so a 10 cl glass looks nicely filled and holds the crema together. For a cappuccino allow 18 to 22 cl, for a caffe latte 27 to 36 cl, and for a latte macchiato with clear layers at least 36 cl and preferably 45. The taller and narrower the glass, the sharper the separation between milk, coffee and foam stays.
After that you choose by wall type. Single-walled glass shows the colour best but gets hot, so you want a handle or a holder with it. Double-walled glass keeps the coffee warm longer and stays cool enough on the outside to pick up, which makes the coffee appear to float in mid-air. La Rochère covers the decorative side with relief glass in ranges such as Ouessant and Abeille, while Bormioli Rocco, Onis and Royal Leerdam supply the robust catering sizes. Duralex Picardie is tempered and virtually indestructible.