Zirkus Espresso Coffee Knock Box with Silicone Bar

A coffee knock box is used to remove the spent coffee puck from a portafilter after espresso extraction. Instead of knocking the portafilter against a sink or rubbish bin, tap it gently against the knock bar so the used grounds fall into the container.

Keep the filter basket securely locked inside the portafilter, hold the handle firmly and tap the edge of the basket against the knock bar with a controlled motion. Excessive force is unnecessary and may damage the basket, portafilter or knock bar.

When used correctly, a knock box should not damage a portafilter. The silicone-covered knock bar helps cushion contact between the metal portafilter and the bar. Use a controlled tap rather than striking it with excessive force.

The silicone covering helps soften the impact and reduce direct metal-to-metal contact during use. It can make puck removal quieter and help protect the rim of the filter basket, although some sound is normal when knocking out coffee grounds.

A wet, broken or firmly stuck puck can result from the coffee dose, grind size, basket design and extraction conditions. Allow excess water to drain briefly, then use one or two controlled taps. Avoid repeatedly striking the portafilter with excessive force.

Empty the used grounds, then rinse or wipe the container with warm water and mild detergent. Clean around the knock bar and any corners where coffee residue may collect. Dry all parts thoroughly before putting the knock box back on the counter.

Used coffee grounds can commonly be added to a suitable compost system in moderate amounts. Remove them from the knock box regularly and follow the requirements of your local composting or waste collection service.