What is an indicator of poorly steamed milk?

A burnt taste in steamed milk is a strong indicator that the milk has been overheated or improperly steamed. When milk is steamed at the right temperature, it should reach a sweet, creamy flavor without any burnt notes. The milk should be heated to a temperature range that allows the natural sugars to caramelize slightly, producing a rich, smooth taste. If the milk has been allowed to reach temperatures above around 150°F (65°C), it can begin to scorch, leading to a burnt taste that negatively affects the final beverage.

In contrast, a shiny surface can occur with well-steamed milk, indicating that air has been incorporated effectively. A velvety texture is a desired characteristic of properly steamed milk, offering a smooth mouthfeel that complements espresso. Consistent foam reflects good aeration and microfoam creation, which are signs of skilled milk steaming. These characteristics enhance the overall quality of espresso beverages rather than indicate issues with steaming. Thus, it is primarily the burnt taste that directly signals a failure in the steaming process.