Deep bed filters
Sheet filters are prefabricated, three-dimensional deep bed filters, which, unlike two-dimensional screen filters (membranes), only develope their 3D structure during the filtration process(diatomaceous earth filters).
Deep bed filters are generally considered to start from a layer depth of 0.5 mm. The 4 mm thick filter layer of the sheet filter is formed between plates and is used for the discontinuous filtering of liquids.
The filter layers are formed of between 30% and 50% by weight of cellulose. The remainder is formed from various additives like diatomaceous earth or perlite and a plastic dispersion for better stability.
There is little need to fear adverse influences on the wine from the materials themselves. However, if the materials are improperly stored, they can absorb odours from the environment which can then be passed on to the wine.