I have to use all my strength plus upper body weight to depress the plunger. Sometimes brew shoots out the sides of the top of cup in the process. I follow all Aeropress instructions, use both inverted and upright press positions, and Starbucks ground coffee. I store the maker with plunger inside tube and use Aeropress filters. I have read several letters from others who were unable to resolve the issue. What do you recommend? P.S. The coffee once made is very good, though. I don't want to give up on it. Thanks. – From Christine D.