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Blind disc / blind basket / blanking disc
A solid rubber (or metal) disc that fits into the portafilter to block flow, used for backflushing or OPV adjustment.
Category: Maintenance & Servicing
A solid disc (no holes) shaped like a filter basket, used in place of the regular basket during backflushing. Water flows in but can't escape forward through the puck, so it routes through the 3-way solenoid into the discharge line.
Why it matters — A blind basket is required for any backflush — water-only or detergent. It's the cheapest single tool you should own if you have an espresso machine with a 3-way valve.
Good to know
- Match the size to your portafilter (58 mm for most commercial; 53 mm for Breville).
- Some blind baskets have a small pressure-relief hole for use with OPV gauge kits — make sure you have the right type for your purpose.
Related: Blind Baskets