Why it matters in the cup.
Coffee glossary
Backflushing
A cleaning process that sends water and cleaning solution back through the brew path of a compatible machine, clearing old coffee oils and residue from the group head, shower screen, and three-way valve.
Filed under
Problems that show up later
Problems that show up later
What it means
A cleaning process that sends water and cleaning solution back through the brew path of a compatible machine, clearing old coffee oils and residue from the group head, shower screen, and three-way valve. Old oils turn rancid quickly and can taint every shot pulled afterward — skipping backflushing for too long makes the machine taste dirty even when the coffee itself is good.
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Where this leads
Each one pushes this into the cup, compares it, or helps you act on it.
Parts that change the shot
Group Head
Maintenance matters because parts touch the coffee directly.
If shots turn erratic, check the group before the grinder. Flush and wipe it so residue and poor heat do not leak into the cup.
Parts that change the shot
Portafilter
Service cleanliness starts where the coffee sits.
Keep the portafilter clean, hot, and dry before dosing if you want repeatable shots.
What people mean when they say "extraction"
Espresso Extraction
Dirty equipment still shows up in the cup.
Separate extraction from strength in your thinking. One asks how much was dissolved, the other how concentrated the drink feels.
Parts that change the shot
Steam Wand
Cleaning habits matter on the milk side too.
Purge before steaming and wipe immediately after. Clean steam habits matter as much as pouring skill.