I've been using my coffee syphon for a year+ now. It became a ritual for me and it makes a good cup. The past month or so I've run into a problem that I can't find any answers to, hoping someone here has seen this.

When I remove the syphon from the lamp, it will draw down about half way then stop. The rest of the coffee is sitting up top refusing to come down. The pressure doesn't release as quickly as it used to, but I think something else is the problem.

• I've stirred to ensure the grinds aren't blocking
• I've pried the two chambers apart - I can hear the pressure release, this itself doesn't solve it either
• I've dumped the contents of the top to another container and cleaned out the grinds then added it back, it still sits up top

The only thing I can think of is the filter, but some of the coffee can go through.

Using the Hario NXA-5 and Yuchengtech lamp.