An Inexpensive Homebrew Filtration System

Marty Tippin (martyt@pobox.com)

Original: March 21, 1996
Last Update: August 21, 1998


August 21 1998: Since my interests have shifted away from homebrewing, I've sold all my equipment and am essentially out of the hobby for now - but these pages will remain online for the foreseeable future. And I'll still be around to answer questions, so don't hesitate to e-mail me!
-Marty


The following describes how to build an inexpensive dual-purpose homebrew filtration system that can be used for:

NOTE: These plans are intended for homebrewers who keg their beer using the 5 gallon "Cornelius" kegs and a CO2 cylinder for artificial carbonation and dispensing pressure. While it might be possible to adapt this system for gravity-feed use without kegs, the filtration process would be painfully slow and I don't recommend it. In addition, the finished beer filter will remove nearly all yeast from your beer, which means bottle conditioning is not an option.


Background Information

I had considered filtering my homebrew for quite some time and had drooled over the various filtration kits advertised in Zymurgy and elsewhere. The cost of these kits was prohibitive, however, ranging from $70 to $100 or more. There had to be a better way.

I tend to be a gadget freak and seem to have accumulated nearly every homebrewing toy there is (see my Two-Tier Converted Keg Brewing System if you don't believe me). I'm always looking for new stuff to buy or build, so one day while wandering aimlessly through our local mega-homebuilder-supply store, I ran across some whole-house filtration systems that appeared quite similar to the kits I had seen advertised. A little light went on in my head and I thought, "I bet I can build one of these cheaper than I can buy it!" With that challenge in mind, I set out to see what I could do.

Fortunately, at nearly the same time that I ran across the filtration systems at the hardware store, there was an article in the Jan/Feb 96 issue of Brewing Techniques that described how the filter systems worked and gave some contact information for various suppliers. That article formed the basis for my work and I highly encourage you to read it if you can; there's a lot more theory in that article than I intend to present here.

Why filter your finished beer?

If you're like me, you commonly have problems with haze in your finished beer. Seems that no matter what I do - Irish moss, gelatin finings, polyclar, etc. - I still end up with beer that's not a bright as I'd like it. Some brewers make beer that becomes crystal clear; I envy them. Others say that if haze really bothers you, you should drink from an opaque mug or just close your eyes.

Haze in your finished beer can come from many sources, including the yeast (which imparts a permanent haze, no matter what the beer temperature). Larger proteins that are not metabolized by the yeast can remain in suspension, dissolving in the beer at certain temperatures but coming back out of solution when you chill the beer - that's chill haze.

I don't intend to go into great detail about what causes haze and what the different kinds are; you can refer to a number of recently published articles and/or homebrewing texts for that information (see references above). The important thing to note in this context is that filtering to 5.0 microns will remove most of the yeast; filtering to 1.0 microns will remove many haze causing particles in your beer; filtering to 0.5 microns will remove nearly all chill haze causing proteins as well. Filtering below 0.5 microns can have detrimental effects on your beer, as many of the vital components of the body, flavor and head will be removed. I'd encourage you to experiment with different micron ratings and see which you like best; I personally can't taste any difference in unfiltered beer and beer filtered to 0.5 microns.

Why filter your brewing water?

Most municipal water systems chlorinate your water to inhibit the growth of bacteria. Unfortunately for the homebrewer, using chlorinated water for brewing can have disastrous consequences for your beer - the chlorine can form chlorophenols in the wort and give some nasty phenolic/medicinal flavors and aromas to the beer. Simple solutions to this problem would have you pre-boil your brewing water; if that works for you, go ahead. I personally don't have time or energy to mess with it and would rather be able to have all the chlorine-free water I want, on demand. That's where the filtration system comes in.


The nitty gritty

This system is based around the whole-house filtration units made by Omni, Ametek and others, and commonly available at most hardware stores. These units use standard 10" filter cartridge elements which come in a number of varieties for various filtration tasks and are generally inexpensive and easy to get. Generally, the filter units are installed in homes and used to filter taste, sediment and even lead from drinking water, but they are also perfectly suited to homebrew use. The unit has standard 3/4" female pipe threads for attaching it to whatever source and destination plumbing you have, as well as a purge valve in the top for releasing air and/or pressure in the unit.

The filter cartridges are cylindrical, about 3" in diameter and have a hole in the center of about 1" diameter. The filtration system works by passing the liquid into the filter housing, through the filter cartridge from the outside, and finally back out of the housing. The cartridges are securely sealed into the housing when the base is screwed on, and all liquid is forced to go through the filter before it can come out the other end of the housing.

Parts List:

Filter Cartridge sources:


Filtering your beer

Assembly is no big deal - for filtering your finished beer, you need a keg with the unfiltered beer in it (uncarbonated!), the filter and an empty keg to put the filtered beer into. Rig up the filter so the liquid out from one keg goes into the filter and the output of the filter goes to the liquid in of the empty keg. Use low pressure (around 5 to 10 psi) to push the beer through the filter and lift the pressure relief valve on the empty keg. The colder your beer is when you filter it the better, as many of the protiens that make up chill haze can be brought out of suspension and filtered at lower temperatures. As the filter gets filled up with gunk, you may need to increase the pressure to keep a reasonable flow rate. I wouldn't recommend pressure higher than 20 psi or so - if it takes more than that, your filter is clogged beyond use and you can try backflushing it or just buy a new filter.

After using the filter, you can backflush it with a mild bleach solution in warm water, pushing the liquid very gently through the filter in reverse. Keep the pressure low when backflushing or you'll damage the pleats in the filter! Store the filter in a ziploc bag in your fridge - the bleach solution should help keep the nasties from invading.


Copyright, disclaimer, and other nonsense

This document is copyright 1996 by Marty Tippin (martyt@pobox.com). However, you may freely copy and distribute it for any non-commercial purpose, provided this copyright notice remains intact. I didn't pay anything for the information I used to design my system shouldn't have to either - if this document is helpful to you, then and you feel free to use or Anyone wishing to publish this information or otherwise use it modify any ideas contained in it! commercially (whether in part or in whole) should contact me for permission first.

By way of disclaimer, I am not responsible for anything boneheaded you do that gets you hurt, arrested, expelled or even deported. (thanks, Beavis & Butthead…) Use some common sense and you should be fine.

And if there's anything blatantly wrong or otherwise in need of correction in this document, or if you've got suggestions, questions or just need to unload on someone, please let me know - there's a link to my e-mail address at the top of this document. And if you decide to build a system based on this design, I'd appreciate if you'd send me some pictures and let me know how it worked and what you did differently!


Comments, questions, and suggestions for improvement are welcome! Send them to the author (e-mail address at the top of this page)