Modern semi-auto espresso machines are starting to add pre-infusion to the process. Lelit, Rancilio, Profitec, ECM…
But there’s also a belief that just wetting the puck prior to brewing doesn’t do much. The water should, at least, be under mild pressure (e.g.: 2bars) otherwise it’s a bit pointless.
So I tried the manual way: ground the coffee, distributed and tamped. Then, using the hot water tap of the Elizabeth (it’s from the brew boiler so it’s the right temperature) I wetter the coffee puck, and then locked and pulled my shot. The shot ran faster, and it tasted slightly different than usual (obviously).
Has anyone tried that? I tried a few times and I can consistently repeat he results.