Mash Filter, a wort separation device that can be used as an alternative to a lauter tun or a mash/lauter vessel. The mash filter is essentially a plate and frame filter press fitted with series of fine filters for separating spent grist from sweet wort. Whereas older mash filter models were often criticized for providing hazy worts with high levels of unwanted polyphenols, modern mash filters are highly efficient and can produce bright worts with few particles.

In 1901, the Belgian Philippe Meura developed a filter press to improve the mash lautering process. The company that bears Meura’s name is still making mash filters. The mash filter, unlike the mash tun, is able to handle very fine grist crushed by a hammer mill, and this ensures exceptional extract recovery. A modern mash filter is a series of polypropylene filters, which can handle grist of up to 100% adjunct because barley malt husks are not required to act as a filter medium, as is the case with a lauter tun.

Once the first wort has been run off into the kettle, sparge liquor can be introduced into the filter and a weaker wort can be extracted. Sparging continues until the required amount of wort has been collected. Some systems allow the mash to be physically squeezed dry after sparging has been completed. At the end of each cycle, the filter is opened and the spent grains, almost dry, are allowed to drop out. A modern mash filter can filter large volumes of wort very quickly, enabling some brewers to process more than 12 brews per day. There are some disadvantages. Compared with a lautering vessel, the mash filter can be difficult to use when a brewery employs a wide variety of mash sizes because the range of optimal loading for the press is relatively small. Some brewers argue that the lauter tun remains a superior mash separation device and produces better quality wort. Mash filters remain rare in the United States, but they are widely used in Europe and other parts of the world.