Final answer:
The sign of a 'good roll' when steaming milk is frothy and bubbly. When steaming milk for a latte or cappuccino, the goal is to create a creamy and frothy texture.
Step-by-step explanation:
The sign of a 'good roll' when steaming milk is frothy and bubbly. When steaming milk for a latte or cappuccino, the goal is to create a creamy and frothy texture. This is achieved by introducing air into the milk while steaming it, which creates bubbles and gives the milk a lighter and smoother consistency.