Every few weeks, my 4-cup Starbucks Barista Quattro coffee maker overflows. It seems that the water either flows into the basket too rapidly or out of the basket too slowly. The basket overflows, and liquid and grounds go everywhere. Cleaning the coffee maker doesn't really seem to help.

There is a flaw in the design of the Quattro that affects some users more than others. The gap between the outside cap of the carafe and the inside moving cover is suppose to work as a vent to allow pressure to escape. On some units, the tolerance is very small which allows condensing steam to create a seal in the gap once it turns back into water. This creates a high pressure "bubble" in the cap which then doesn't allow the coffee to enter the carafe.

A simple solution is to drill a small 1/8" hole at the top of the inverted cone in the cap. That allows the pressure to escape. I suppose you could put the hole anywhere at the top of the cap and it should work the same.

If your in a hard wayter area the basket overflow valve may be need cleaning. Fill with white vinegar and run a full cycle. Rinse by running 2 or 3 cycles with clean water. You may need to repeat the vinegar cycle if the problem persists.