[briansmith7011]

Does anyone have experience with either a cartridge or plate filter for beer? any reviews or thoughts on these? I've read pros and cons of beer filtering in general and understand the techniques used to produce clearer beer without mechanical filters - this post is for anyone that may be interested in considering filtering equipment to augment non-mechanical means. My particular interest would be for competition beers (lights and pales) on special occasions (not everyday use).

[Robert]

If you understand the pros and cons of filtering,  you know that stripping is one big con, and oxidation is another.  Plate filters are much less of a problem with regard to stripping.  I filtered my beer for many years using plate filters.   You can get visually absolutely brilliant beer (like Budweiser clarity) just with coarse, 6-7 micron pads.  But I'll say that even these do strip some degree of body, foam capacity, flavor and aroma from the beer, and it's virtually impossible to filter by any method at the homebrew level without introducing some oxygen, so staling is significantly accelerated.   For these reasons I've quit filtering, and am trying to train myself to accept a bit of turbidity in exchange for an improvement in everything else.   But if you're going to filter, I strongly recommend a plate filter and coarse pads.  If you can't "do no harm," do the least.

[KellerBrauer]

If God wanted beer to be clear, He would NOT have given us kidneys!   

[RC]

I use a plate filter occasionally and find that it works great. I haven't had any of the issues Robert describes, including oxidation. But the 5-7 micron filter pads won't cut it. Yeast are ~4-ish microns, so most of the yeast cells will slip right on through. You need the 1-2 micron pads to get really clear beer--but give the beer a lengthy cold-crash settling time first, and with fining, to get is as clear as possible, as the 1-2 micron pads clog very easily.

What's often overlooked with filtering at the home-brew level is the need to remove the paper flavor from the pads before using them. When people say that the plate filters lead to oxidation, I suspect that it's because people are tasting the paper flavor from the pads and mistaking it for oxidized beer. Acidity helps remove the paper flavor. I soak the pads in a strong star-san solution, not to sanitize them but to help remove this flavor. (A stronger acid would work better but star-san the best I can do. Commercial breweries use a combo of citric and nitric acids.)

I boil 3 gallons of distilled water, cool it and put it in a keg, then bubble CO2 through the water via the beer-out line to strip out as much O2 from the water as possible. I assemble the filter and push this water through the filter pads, tasting it as it comes out. You'll taste the paper flavor at first but it'll eventually go away. For me, this takes about 3 gallons of water. Then I'm ready to filter.

If it sounds like a huge PITA, it's because it is, which is why I don't do it very often. But I've never had an issue with oxidation or flavor stripping. I'm not saying these don't occur, I'm just saying that neither I nor beer judges have ever perceived either of these problems in my post-filtered beer.

[Robert]

I use a plate filter occasionally and find that it works great. I haven't had any of the issues Robert describes, including oxidation. But the 5-7 micron filter pads won't cut it. Yeast are ~4-ish microns, so most of the yeast cells will slip right on through. You need the 1-2 micron pads to get really clear beer--but give the beer a lengthy cold-crash settling time first, and with fining, to get is as clear as possible, as the 1-2 micron pads clog very easily.

What's often overlooked with filtering at the home-brew level is the need to remove the paper flavor from the pads before using them. When people say that the plate filters lead to oxidation, I suspect that it's because people are tasting the paper flavor from the pads and mistaking it for oxidized beer. Acidity helps remove the paper flavor. I soak the pads in a strong star-san solution, not to sanitize them but to help remove this flavor. (A stronger acid would work better but star-san the best I can do. Commercial breweries use a combo of citric and nitric acids.)

I boil 3 gallons of distilled water, cool it and put it in a keg, then bubble CO2 through the water via the beer-out line to strip out as much O2 from the water as possible. I assemble the filter and push this water through the filter pads, tasting it as it comes out. You'll taste the paper flavor at first but it'll eventually go away. For me, this takes about 3 gallons of water. Then I'm ready to filter.

If it sounds like a huge PITA, it's because it is, which is why I don't do it very often. But I've never had an issue with oxidation or flavor stripping. I'm not saying these don't occur, I'm just saying that neither I nor beer judges have ever perceived either of these problems in my post-filtered beer.

I used a similar procedure as you, but sometimes simplified by using SMB or PMB to deoxygenate the flush water.  I would cold crash, but not fine -- that just potentially adds to the filter load -- and have never noticed one bit of difference in clarity between coarse pads and 2 microns.   Some live yeast will pass through but that can be good for preserving the beer; dead yeast and colloidal material will be held back.  The stripping effect I have definitely found is greater with tighter filtration.  And rapid oxidative staling.  After I don't know how many batches, but probably in the neighborhood of 100, I see little upside besides visually impressive clarity.   But when the stars align and the beer gods are well disposed, that is possible even without filtration.   Just rare.  Apparently YMMV.