To achieve excellent filtration results stainless steel filter elements (stainless steel frames) are used as the carrier for the DE (Kieselguhr). The filter elements are first covered with coarse and subsequently with finer DE type.
The so-called ‘pre-coat’ is the basis for the good beer filtration effect. The first pre-coat with coarse DE type is injected into the filter internal recirculation loop filled with de-aerated water, and the whole process takes approx. 15 minutes. The same happens with second pre-coat where medium and/or fine DE types are used.
After the pre-coat has been done, the de-aerated water inside the filter is pushed out with unfiltered beer until the necessary sales gravity at the inlet of the bright beer tank has been reached.
The re-use (re-covering) of the beer/de-aerated water mix guarantees very low extract losses and very short down times. During whole filtration process some DE is injected into the main beer flow at the inlet of the candle filter to avoid a fast blocking (delta p) of the DE cake.
At the end of the filtration process beer is pushed out with deaerated water, and as soon as the extract value is below sales gravity, the beer / de-aerated water mix is recovered for adding it during the next filtration cycle.