How useful is pre-wetting and pre-infusion?
Here are my thoughts on pre-wetting and pre-infusion when it comes to manual Italian coffee machines.
Pre-wetting (gravity fed water dribble)
Consensus seems to be that pre-wetting is of negligible benefit and my own experience leads me to the same conclusion. This means that you should skip pre-wetting.
Pre-infusion (mains pressure fed water stream)
For Italian coffee machines with standard groups the benefit of mains pressure pre-infusion is significant because it prepares the coffee puck for the high initial pressure hit that a standard group delivers.
For Italian coffee machines with E61 groups the benefit of pre-infusion is negligible because E61 groups are designed for passive pre-infusion followed by gentle pressure build up. Passive pre-infusion is effectively engineered in to every E61 group.
So what does all this mean?
Firstly, forget all about pre-wetting. Secondly, mains pressure pre-infusion is useful for manual coffee machines with standard groups but the benefit is negligible for coffee machines with E61 groups. The E61 is legendary for good reason. So my advice is to get an Italian coffee machine with an E61 group and forget all about pre-wetting and pre-infusion. Just pull the lever and let the E61 group work it’s magic.