Turning OFF the grill when the espresso maker is ON
Go with  @Wouter van Ooijen's suggestion:







simulate this circuit &ndash; Schematic created using CircuitLab

Cut the wiring / trace at either end of the relay coil on the grill. Bridge them with a normally closed reed switch. By experiment find out how many turns of expresso wire you need to get the reed switch to change over and add, say, another 25% to give reliable switching.

No electronics!