What is the function of steam wands in espresso machines?

The function of steam wands in espresso machines is primarily to froth and texture milk, which is crucial for preparing milk-based coffee drinks such as lattes and cappuccinos. When steam is produced by the espresso machine, it is directed through the steam wand. As the steam is introduced into the milk, it creates microbubbles, which increase the volume and improve the creamy texture of the milk. This process enhances the sensory experience of the drink, allowing for a velvety mouthfeel and better integration of the milk with the espresso.

This capability transforms the overall quality of the beverage, enabling baristas to create beautiful latte art and ensuring that the milk complements the espresso effectively. In contrast, the other options do not accurately represent the main function of steam wands. For instance, extracting espresso is done through pressurized hot water, not steam, while brewing coffee typically involves filter coffee methods rather than steam wands. Additionally, cooling down hot water is not a function served by steam wands, which are designed for creating hot steam rather than reducing temperature.