The lauter tun wedge wire screen allows the solid grain components of the mash to act as a filter to separate the wort. While the slot openings of the lauter screen false bottom don’t technically act as a filter in the process, they enable the most effective filtration to occur by supporting the grain, which itself becomes the filtering medium — holding back the smallest solids while allowing the wort to pass. A high-quality, tight tolerance construction is necessary to help ensure that the process occurs correctly and uniformly so that the resulting product — whether beer, liquor or wine — is not bittered or otherwise compromised by components that shouldn’t be part of the wort.