Beer Trap Filtration


Once beer has been brewed (fermented and aged), it must be filtered to remove residual yeast and undissolved organics. Most breweries filter beer through diatomaceous earth (DE) pre-coat filters just prior to packaging or, in case of the newer draft brewed beers, just prior to the aseptic or cold filtering process. Cartridge filters are located downstream of the DE filters to trap DE, yeast and undissolved organics which pass through the DE filters.

Wound or melt blown depth cartridges are the most common trap (or beer polishing) filter cartridges as used in the US brewing industry.

The trap filter, including cartridges, is periodically sanitised by back-flushing with hot water at 82 ºC to 91 ºC for up to 30 minutes. Sanitisation is done not only to prevent microbial growth but also to increase cartridge life. Depth cartridges are not well suited to backwash purposes. It is difficult to flush out particles collected within the fibre matrix in either wound or melt blown depth cartridges. In addition, the fibre matrix in wound cartridges can shift during backwash causing reduced efficiency when filtration resumes.

The Poly-Mate XTRA duty and Abso-Mate polypropylene pleated cartridges eliminate the deficiencies of depth cartridges. The surface type media, with thermally-bonded fixed pores, releases particles readily during backwash. A rigid exterior support cage and a glass fibre reinforced core provide dimensional stability required for hot water back-flushing.

Poly-Mate XTRA duty one micron rated cartridges (PXD010) have been successfully substituted for one micron nominal or 5 micron absolute melt blown depth cartridges in beer trap filters.

The hot water used to sanitise / back-flush the trap filter cartridges must also be filtered. To prevent fouling of the downstream (clean) side of the trap filter cartridges, PXD005-30FA-DO cartridges are being used to provide clean hot water.

Case Study:

A major US brewery had been using 1 Fm nominal wound cotton cartridges as beer trap cartridges. The trap filter housing was designed to handle 275 barrels/hour (32,270 litres/hour) through 49 triple length cartridges (30" at 3.785 litres per minute per 10" cartridge) for optimum yeast and DE removal. The system was either sanitised on a weekly basis or when the pressure drop ()P) rose above 1.38 barg. A set of wound cartridges normally lasted about two weeks or 7,040,640 litres of beer. However the brewery could not effectively increase the flow rates to sufficiently meet the demand during peak production periods. When the flow was increased, the pressure drop would increase rapidly requiring frequent back-washes which interrupted flow to the packaging area. Yeast and DE counts would often exceed specified limits following backwash.


- PXD010-30FA-DO (Beer Trap Filter)
- PXD005-30FA-DO (Sanitising water)

Beer Filtration Applications:

- Beer Stabilization (Final filtration)
    - Also called "aseptic brewing"
    - Also called "cold filtered" beer
    - Remove ber spoilage organisms:  
        > Lactobacillus
        > Pedioccus
    - 0.45 or 065 um Nylon / Polysulfone membrane cartridges
- Beer trap (polishing) filtration
    - Remove yeast and Diatomaceous Earth (DE)
    - Clarify beer
    - 1 to 30 um nominal (3 to 10 um absolute)
- Process and rinse water