Beans Sticking in Hopper on Superautomatic Espresso Machine - Delonghi, Saeco, Jura, Gaggia

Dirty water in my cup?? Yuck!!
This happens all the time, especially when using dark roasted oily beans.
What happens is that the oils from dark roasted, oily, old, stale beans build up on the hopper of your machine and cause the beans to stick. Think of the oil as glue... the oils will hold on to eachother and when your beans stick to your hopper, nothing falls down into the grinder and you are left with dirty water.
Try using fresh, medium roast coffee for best results. When you notice you run out of beans, take the time to wipe down the hopper with a wet towel. Don't use soap or any cleaners as the taste will transfer to your coffee.
This applies for saeco, delonghi, jura, krups and most other super automatic espresso machines.