For steamed milk, how much does the temperature increase for small tins?

The correct choice indicates that the temperature of steamed milk in small tins typically increases by 20 degrees. This increase is significant as it reflects the standard temperature range for steaming milk to create microfoam, which is essential for crafting high-quality espresso-based drinks. When steaming milk, achieving the right temperature is crucial for both texture and taste.

A temperature increase of 20 degrees strikes a balance between creating a pleasant drinking temperature while also allowing the milk proteins to denature properly, enhancing sweetness and improving overall flavor. Notably, the other temperature increases proposed, while plausible, do not align with the commonly accepted practice in the preparation of steamed milk used in coffee beverages.