Help!! I've used my Aeropress for years, with one replacement of the rubber seal. Three months ago I got a new Capresso Infinity grinder which was working just fine, set around the middle of Fine or between Fine and Extra Fine. Things were good. All of a sudden, about a week ago, I can no longer push the plunger all the way down. It stops about 3/4" from the bottom. My husband couldn't even move it. I can push it all the way down only if I use a grind so coarse that the coffee tastes like water. Same coffee, same water, same batch of filters. Pushes out OK when I remove the end cap. I've put in a call to Jura because I think it has to be the grinder – but is there any possibility that it's the Aeropress? Any advice? – From Ellen M.

Sticky coffee oils can build up in the chamber. If the inside of the chamber feels sticky when you drag you finger on it, then clean it and the rubber seal with vinegar. After that wipe a bit of vegetable oil on the edge of the seal that contacts the chamber. If the problem persists, then it probably is the grinder. Remember too, that it's easiest to press gently.