We consider a thinner chassis better because it makes the product more compact and portable. Thinness is a feature highlighted by many manufacturers of mobile devices, but it is essential for a wide range of products.
A PID controller controls the temperature of the boiler electronically. It offers a far greater degree of accuracy and consistency than a regular, mechanical thermostat used to control temperature. This is very important as a temperature of around 92°C to 96°C is key to pulling the perfect espresso.
These buttons can be programmed for different types of coffee such as an espresso, doppio or ristretto. This means once you have mastered a particular style of coffee, you can get it the same every time.
A higher number of grind settings gives you more flexibility when choosing the fineness of your ground coffee. The particle size is important as a grind which is too coarse can produce weak tasting espresso, whereas a grind which is too fine can lead to a bitter taste.
With a pre-infusion function you get a low pressure of water before it ramps up to around 9 bar of pressure. This gently expands the grinds to get a smooth extraction and to help prevent channeling in the cake.