Which size drink would typically contain the most amount of foam?

The size drink that would typically contain the most amount of foam is the extra-large size. Foam is created during the steaming process of milk, and larger drinks have a greater volume of milk, which can be frothed. The extra-large drink allows for more air to be incorporated into the milk, resulting in a higher quantity of foam compared to smaller sizes.

In addition, extra-large drinks generally have more espresso or other base liquids, providing a larger canvas for the foam atop the drink. The combination of a greater volume of steamed milk and the necessary foam ratio leads to a thicker layer of foam on extra-large beverages, enhancing the overall texture and mouthfeel of the drink. Therefore, in terms of maximizing the foam content, the extra-large option is the best choice.