Cover image: representative espresso machine and vessels, not the Classic Pro control layout. Use the exact model manual for buttons and the descaling sequence.
Quick answer: The referenced US Classic Pro manual calls for descaling about every two months with Gaggia descaler, never vinegar. It runs solution through both the steam wand and brew unit with timed pauses, then requires a thorough fresh-water rinse totaling four tanks. Do not drink any liquid dispensed until the entire process is complete. Verify the procedure against your exact Classic Pro revision and the descaler label.
Prepare the machine
Remove the portafilter and empty the tank. Keep large, heat-safe containers and access to a sink nearby; the wand and group can discharge hot liquid. The manual instructs pouring half the descaling solution container into the tank, then adding fresh water to MAX. It does not say to pour the entire bottle. Never mix cleaners or leave solution in the machine overnight.
Solution stage
- With the portafilter removed, fill the tank with half the Gaggia descaler container and fresh water to the MAX mark. Turn on the machine.
- Dispense two roughly 150 mL cups from the steam wand using the manual’s hot-water controls, then two roughly 150 mL cups from the brew unit. Turn the machine off for about 20 minutes.
- Turn it on and repeat two cups from the wand and two from the brew unit. Turn it off for three minutes. Repeat this dispense-and-short-pause stage until the solution tank is empty. Keep hands clear of hot outlets.
Fresh-water rinses
- Rinse the tank, fill with fresh drinking water, and empty the drip tray. With a vessel under the wand, use the brew and steam controls as specified in the manual to dispense the whole fresh-water tank through the wand. Close the steam knob.
- Fill the tank again. Refit the portafilter as directed and place a vessel beneath it. Dispense the entire tank through the brew unit, then remove and rinse the portafilter.
- Repeat those two fresh-tank stages once more: another full tank through the wand and another through the brew unit. That is four fresh-water tanks in total, not four cups. Refill with fresh water for normal use and prime the circuit if necessary.
If flow remains poor
Descaling may not fix a dry or unprimed water circuit. Follow our no-water-from-group diagnosis. A dirty basket or shower screen needs the separate cleaning routine. Stop and contact service for electrical faults or internal leaks.
FAQ
Can I use vinegar?
No. The referenced Gaggia manual explicitly disallows it.
Can I stop after one rinse tank?
No. Follow all four full-tank rinses specified in this manual.
Source: Gaggia Classic Pro US instruction manual, “Descaling.” Model revisions can differ.