What are the differences between a pressurized and non-pressurized basket for espresso machines?

The main difference between a pressurized and non-pressurized basket for espresso machines is how they control the flow of water through the coffee grounds. Pressurized baskets use a valve to create pressure, resulting in a more forgiving extraction process that can produce crema even with pre-ground coffee. Non-pressurized baskets rely on the user's technique to create the right pressure, allowing for more control over the extraction and a potentially higher quality espresso.