Espresso Not Coming Out While Pump Turned On

Question

I just purchased a used Gaggia Espresso Color (not sure how long it's been used nor maintenance) and am running into an issue (doesn't happen every time) where when I turn on the pump to pull a shot you can hear the pump on and working but no espresso comes out.

After 20-30 seconds the sound from the pump becomes quieter. But, if I turn the pump off for a few seconds and then turn it back on espresso does start coming out.

This is my first time making espresso so not sure if it's user error or an issue with my used machine. I just ordered some descaler online to descale it as I'm assuming the machine hasn't had much maintenance.

For reference I'm using a medium roast and a Baratza Virtuoso grinder.

Answer 1

Some things to try:

First, run the pump briefly with no portafilter in place. You should see a nice shower of water flow from the brew group. If you don't see a nice shower flowing, the shower screen on the portafilter might be clogged (or there might be a partial clog elsewhere in the system). If this is the problem, clean your shower screen, then do a backflush routine.

Your grind size might be too fine. If there is no sign from a leak above but your spent pucks come out soupy, this could be your problem. Dial the grind down a tick or two and try again.

The pump might be dying. This unit uses a vibration pump, a type of pump that is susceptible to failure but also easy to replace if it fails. A damaged pump might not produce sufficient pressure to drive water through your coffee. If you increase your grind size to get good flow but then get weak tasting brews with no crema, the pump might be to blame. Contact Gaggia support for information on purchasing a replacement part and how to do the repair if this is the problem.

Answer 2

I'm guessing that the coffee, in those cases where it does come out, is flowing very slowly, just dripping?

Your coffee is either too finely ground, or too much. or both, so that the pump struggles to force water through the puck. When you turn of the pump, you're releasing the pressure on the puck, which disturbs it (makes it uneven) so that you get channeling, ie. spots in which the water can flow more easily.

Try to grind coarser, and/or use less grinds.

Since you mention it takes 20-30 seconds until the pump gets quieter (which is when the pressure has built up), another posibility is that the pump is broken, or the machine full of limescale. As this should only take maybe 5 seconds.

Answer 3

Make sure you are not tamping the coffee to hard. If you tamp it too hard into the portafilter, this can happen. As others mentioned, too fine a grind can cause issues (Turkish for example vs. Espresso).

Also, look at the manual for your machine and prime the pump before making espresso. Priming ensures there is proper suction and no air in the hoses, and once the machine is primed, you will rarely need to do this again unless your tank gets empty and air syphons back through.