For what its worth, despite missing the punchline of the actual measurement, the guy knows what he is talking about. Taking a dB measurement in C weighting over some integration period is how to do it for this scenario. I doubt his meter is calibrated but its doing a good job.

Just because they’re doing this to chase money to fund their research doesnt mean it couldn’t potentially make a better cup or coffee at home. I think its a britllant idea where heat makes the coffee bitter, perhaps there’s a magic ratio of heat and ultrasound to make a majestic cup of Joe.