Sterile Filtering

[beermkr]

Wondering if anyone has experience daisy chaining a sterile cartridge filter after a DE filter.

We want to start sterile filtering but do not have 2 bright tanks. My intention is to DE filter and run its output directly into the sterile filter.

Based on this should I get a 3 cartridge filter to ensure flow rates? or would a single cartridge be fine. (30hl per hour)

Also what is the service life of a filter. I assume they can be back flushed and cleaned since they are expensive.

Mike Pensinger
Williamsburg AleWerks

[dick murton]

You can trap filter immediately after DE. You will need to protect your 0.45 micron cartridge from blinding by first passing the beer through a particulate trap filter - normally 5 micron is OK. I don't suggest you go up to a 10 micron as it may let too much through.

You can get cartridge housings pretty much any capacity you want. If you need say a two cartidge housing, sometimes you will get a 5 cartridge housing (for example) with 3 fittings blanked off.

You need to allow for hot caustic soaking of the cartridges, to flood with casutic at circa 65 C, and leave to soak, then forward flush with cold water, and finally, just before use, backflush at 150 % of forward flow design rate. If you look after them, they will last months. If you cannot flush them properly, they will blind sooner. Fit pressure guages per and post filter housings. If the DP exceeds more than a few PSI then they are starting to blind. You need to backflush separately to drain, so it gets pretty messy, whether as a manual operation or automated (sometimes I think manual would be easier than automated)
Sterilisation - read the suppliers instructions, normally a cold terminal sterilant as heat softens the cartridge plastic housing too much


Have fun

Cheers

[bigdogbrewer]

I have a sterile cartridge filter (.45 micron), however I use it inline from the bright tanks to the keg filler. I use the 5 micron cartridge as a DE trap filter coming out of the filter outlet.

Read the cartridge instructions for cleaning/sterilizing cartridge filters because polysulfone type filters can not be back flushed.

[Jim Russell]

As previous poster stated you want to have a nominal trap filter in place, I'd prefer a 3 um if you are using a cellulose fiber precoat on your DE bed. If you aren't using cellulose you might think about it, usually 1-2 cups for a 3-5 sq meter filter are enough and will mean less bleed through for DE and easier clean up after.

As for membrane filtration most breweries I know of are using 0.65 um as standard for beer, and will give the best shelf life from a biological standpoint. Standard lab testing will verify this or a cyclical cold/warm accelerated test for shelf life viability.

With a membrane you might still want to use a cartridge prefilter at a 1.2 um, this is a nominal filter and will provide the best protection payback for your membrane life.

Hope it helps,

Jim Russell

AFTEK inc
Rochester NY