Coffee machine trips circuit breaker
It sounds like there is other equipment on this circuit of which you are unaware.  Perhaps your refrigerator?  It's a common intermittent load in kitchens that could easily pop a breaker in combination with a coffee maker.

Your electrician should have measured amperage draw inside the electrical panel when he swapped out the breaker.

Invite the electrician back over, for some coffee.

You can use a Watts-Up or Kill-a-Watt meter to measure the coffee maker's draw at the outlet:

And the electrician should have an amp clamp to measure at the breaker.