The short answer: stop. Switch the grinder off and unplug it. Do not keep pressing the button to see if it clears. A jam or a sudden grinding, squealing or rattling noise means something is wrong in the burrs or the drive, and running it is how a small problem becomes a burnt motor.
What is safe to do
Once it is off and unplugged, and only then:
- Look in the hopper. Beans, a stone, a piece of packaging. If you can see it sitting in the beans, tip the hopper out. Do not reach down into the throat.
- Leave the adjustment alone. Winding a jammed grinder finer, or forcing it past the point where the burrs meet, is how burrs get damaged. Do not do it to "free it off".
- Do not open the burr chamber. That is where fingers, and the next expensive mistake, go. If it needs the burrs out, that is an engineer's job on that model.
What the noise usually means
A grinder that was quiet and is now grinding, squealing or knocking has usually picked up something it should not have, or the burrs are meeting when they should not. You cannot tell which from the bar, and the fix is not the same. One wants the obstruction out. The other wants the burrs and the setting looked at by someone who knows that grinder. Guessing, with the motor still connected, is the part that costs money.
Then call us
Tell us the brand and model, whether it jammed mid-dose or started making the noise on its own, and whether it still turns at all. We would rather see it switched off on the counter than opened up on the bar. Get in touch and we will take it from there. If the motor smelt hot, the plug sparked, or it tripped the power, say so. Leave it unplugged.