I found that the little security 'umbrella' in the bean hopper that stops a user from sticking their fingers in the grinder is the problem. The little umbrella sometimes gets clogged up for a second or two during the grinding process and doesn't let enough beans through. It doesn't block enough beans so that the machine thinks it is out, but it does block enough so that the brew unit is not full. In the end you do not have enough beans to compress into a puck and you end up with a sloppy mess in the dump bin and a weak shot. I have not had the problem since I removed the safety umbrella. If you feel comfortable with having the grinder open in the hopper (will still have the top lid) then go ahead and remove it, it is just one screw to take it off.