Blind basket & backflush detergent

Seals the portafilter so the machine's own pump pressure drives detergent solution backwards through the shower screen and three-way valve, carrying out the coffee oils no brush can reach.

A blind basket has no perforations. Locked into the group and run, water has nowhere to go, pressure rises to the pump's set point, and the moment the group switches off the three-way solenoid dumps that pressurised water back out through the discharge line to drain. That reversal IS the cleaning action: it carries dissolved oil out of the shower screen, the group's internal passages and the solenoid seat — the only places coffee lipids accumulate and the only ones no brush enters. The detergent is an alkaline powder or tablet that saponifies those lipids so they leave as a suspension rather than a smear. Two consequences follow, and they decide everything else. A machine with no three-way solenoid cannot be backflushed at all — running the cycle on one simply parks detergent in the group. And the same passage that carried the detergent out will carry residue into the next shot, which is why the rinse is not the tidy-up at the end of the procedure; it is half of the procedure.

• Start with the machine, not the chemical. Confirm the group has a three-way solenoid before buying anything at all. If it does not, buy brushes, a soak tub and a screen key instead, and stop — a detergent cycle on a machine that cannot vent is not a weaker clean, it is no clean plus a contamination risk.
• Buy a blind basket for every group and keep a spare. A bar with fewer baskets than groups develops a close where the last group is 'done' with a water flush, and the log will not show which one it was.
• Match the basket diameter to the portafilters you actually run, and check it against a hot group before ordering a case. Baskets that almost seat are the ones that deform.
• Choose the format from who closes the bar. A stable, trained team with a scoop and a label is fine on powder. A rotating closing team should be on pre-measured tablets, because the failure you are buying out of is over-dosing, and over-dosing attacks the gaskets you were trying to protect.
• Buy the product whose label your team can actually read. An instruction nobody on the closing shift can read is not an instruction, and this is a multilingual market — treat label legibility as a selection criterion, not a nicety.
• Ask the supplier for the safety data sheet before the product enters the building, and keep it where the team can reach it rather than in an office drawer. If a supplier cannot produce one, that is the answer to the selection question.
• Buy a pack size the bar consumes well within its shelf life. Alkaline powder that has caked has already lost its dosing accuracy, and a team compensating for cake by scooping harder is over-dosing without knowing it.
• Selecting a chemical is selecting its handling regime — the seven points below are part of the purchase decision, not paperwork that follows it.
• Intended use — dissolving coffee lipids out of the group head, shower screen and three-way valve of an espresso machine. Nothing else. It is not a surface cleaner, not a milk-line cleaner and not a descaler, and it is not interchangeable with any of them.
• Dilution and dose — PER THE PRODUCT LABEL ONLY. This platform publishes no dose for it. The correct quantity is set by the manufacturer's formulation and by your machine's cycle length, and a figure written here would be read as permission to stop reading the label.
• PPE — gloves as a minimum, and eye protection whenever loose powder is handled, because it lifts as dust the moment it is scooped. Alkaline detergent on wet skin is not felt immediately, which is exactly why gloves go on before the first scoop rather than after the first irritation.
• Ventilation — general bar ventilation is normally sufficient for a dosed cycle, but scoop the powder in still air, not under a fan or an open extract that lifts it into the room. Whether the bar's ventilation is adequate for the chemicals stored and handled there is a question for the ventilation designer and the local authority, and this page states no air-change or duct figure.
• Rinse — water-only cycles until the runoff is completely clear and foam-free, then a sacrificial shot per group, discarded and never served. Detergent residue is bitter and soapy and reaches the customer through the same passage that carried the detergent out. The backflush SOP owns the sequence; do not restate it from memory.
• Never mix with — never with descaler or any acid, because alkali and acid neutralise each other and can react in the container; never with any chlorine product; never with a milk-line cleaner. Mixing is almost never deliberate. It happens when a tub is reused or a scoop is shared, so dedicate the scoop and dedicate the tub.
• Storage — in its own labelled container in a chemical store or chemical-only cupboard that holds no food, no packaging, no cups and no lids. Never decanted into a drinks bottle or a food tub. The separation is a HACCP chemical-hazard control, not tidiness, and 'under the counter because the store is far' is precisely how it fails.