This component, a perforated receptacle typically made of metal or plastic, holds the coffee grounds within a brewing device. It allows hot water to pass through the grounds, extracting flavor and aroma, while preventing the grounds from entering the final brew.
A properly functioning unit is essential for a quality cup of coffee. It ensures the correct water-to-coffee ratio for optimal extraction and prevents sediment from clouding the beverage. Historically, various filtering methods have been employed, ranging from cloth bags to elaborate pressurized systems. The modern iteration represents a balance of efficiency, ease of use, and consistent brewing.