What is a common mistake when steaming milk for microfoam?

A common mistake when steaming milk for microfoam is overheating the milk. This is because when milk is heated beyond a certain temperature, typically around 60 to 65 degrees Celsius (140 to 149 degrees Fahrenheit), it can scorch and develop off-flavors, which negatively affects the texture and taste of the foam. Overheating also degrades the proteins in the milk that are crucial for creating stable microfoam, which should be silky and smooth rather than bubbly or dry. Proper steaming aims for a sweet spot where the milk is warm enough to create microfoam but not so hot that it loses its inherent qualities.

While using milk that is too cold, underfilling the steaming pitcher, and not using fresh milk can certainly have impacts on the steaming process and the final result in terms of texture and taste, these issues do not directly contribute to the detrimental effects seen with overheating. Cold milk can produce foam, but it will take longer to steam, while underfilling the pitcher can limit the ability to create proper microfoam, and using non-fresh milk might affect overall flavor and texture, but overheating remains a clear and crucial mistake to avoid in the steaming process.