This graph (click to see the full version) is a continuation of the graph in the previous blog entry, time is still shown in minutes
Here all 6 shots are 16g doses and a pre-infusion of 10 seconds, ending with a 50mL flush to ensure the thermosiphon kicks in promptly as we leave the machine
The purpose of this graph is to show the thermal stability of the LONDINIUM I when pulling back to back shots as everyone has been told that lever groups get hotter and hotter when used in this manner
Lever machines using a dipper design do accumulate heat when consecutive shots are pulled because the group is mounted directly to the boiler with a brass flange
Thermosiphon lever groups do not – the whole idea is that the energy brought into the group (55mL of water at 93C or thereabouts) is offset by the interruption to the thermosiphon as soon as the lever is pulled down/piston raised
To conclude, you only need to pull a flush after the last shot in your espresso session
LONDINIUM I is an exceptionally thermally stable lever espresso machine