A screen filter is a type of filter using a rigid or flexible screen to separate sand and other fine particles out of water. Typical screen materials include stainless steel, polypropylene, nylon and polyester.
In speciality coffee, the screen filter is used with some coffee preparation methods. Coffee passed through a screen filter will have a distinctive profile because it allows coffee oils to pass into the beverage. In contrast, paper filters retain most of the oils, producing a clear cup.
Many times screen filters are built with mesh. Mesh consists of a semi-permeable barrier made of connected strands of metal, fiber, plastic or other flexible/ductile materials. Mesh is similar to web or net in that it has many attached or woven strands.
The best example of a filtering screen is a French press.
Screen filters are also used optionally in automatic drip coffee makers and pour over coffee makers. Users sometimes opt for screen filters instead of paper filters for several reasons. Firstly, screen filters are reusable whereas paper filters are not. This means that screen filters are cheaper in the long run. Secondly, if a paper filter is not rinsed properly, paper taste can sometimes make its way into to the coffee cup. Thirdly, screen filters allow oils through the filter which many coffee drinkers love.