What should be done to the espresso portafilter before brewing?

Before brewing espresso, pre-warming the espresso portafilter is essential for several reasons. When the portafilter is warm, it helps to maintain the temperature of the espresso for a more stable extraction process. This is important because temperature fluctuations can significantly affect the flavor profile and quality of the espresso. A warmer portafilter reduces the risk of cooling the freshly brewed coffee, which can lead to a less vibrant and less complex taste.

Using a pre-warmed portafilter also improves the overall consistency of the espresso shot. This consistency is crucial for achieving a balanced extraction, where the flavors are well-represented and the espresso has the desired crema on top.

In contrast, cleaning and drying the portafilter is necessary for hygiene and maintenance, but it does not specifically address the temperature aspect. Filling the portafilter with coffee is a subsequent step in the brewing process rather than a preparatory action. Calibration is related to ensuring your equipment is set up accurately but does not pertain directly to the preparation of the portafilter before brewing. Hence, pre-warming is the critical step for optimal espresso extraction.