Papierfilter

Papierfilter, or paper filter, is a disposable filtration medium made from porous paper designed to separate solids from liquids. It is used in scientific laboratories and in consumer applications such as coffee brewing, tea preparation, and juice clarification.

In laboratories, filter papers are used with funnels or filtration setups to remove solid material from solutions. They are produced in various grades and pore sizes, commonly classified as qualitative or quantitative. Qualitative filters are designed to capture a range of particle sizes for qualitative analysis, while quantitative filters are chosen for gravimetric work that requires retaining particulates for mass measurement. The choice of grade affects filtration rate and retention.

In consumer contexts, papierfilters are widely used in drip coffee makers (cone and basket styles) and as tea filters. They are usually cellulose-based and may be bleached or unbleached. Sizes and shapes are matched to standard filter holders; pre-wetting can reduce channeling and improve extraction in coffee brewing.

Handling and disposal: after use, filters are discarded and may be composted when clean and unbleached; otherwise follow local waste guidelines. Some filters are designed for higher temperature or solvent-resistant applications, but most are intended for aqueous or steam filtration. Depending on the setting, filters may be replaced regularly to maintain filtration quality and prevent cross-contamination.