Mon Jul 13, 2009 6:02 am
I have used everything from a 1 micron to a 7 micron filter including both the cartridge and plate filter systems.
In my experience with filtering, I do not believe filtering alters the flavor of beer in any adverse way, when using a 1-7 micron range, including both nominal and absolute rated fillers.
I have begun to filter all my beers and have bought the tools (pumps, keg washers,kegs, etc.) to make it easier for me to filter beer with out adding too much extra effort to my process.
I would not use a filter with a micron rating larger than 3 microns nominal. I don't think using a larger micron filter than 3 really does much, although I know that's all that Tasty uses. I would consider a 3 micron filter a rough filter. Morebeer sells both a cartridge and plate filters in this size. You will remove a majority of the yeast (yeast or 1-3 microns in size) and greatly clean up the beer, but you will still have suspended yeast in the beer that will settle to the bottom on your corny over time. You will also not remove chill haze with any filter lager than .45-.5 microns absolute. With that said, this level of filtering is good for all beers styles and will not remove any aroma, color or taste compounds from the beer. The beer will continue to clear in the keg.
3 Micron Nominal (catridge filter from B3)
I use this on all my Ales that are slightly darker that my standard APA (Milds, stouts, Porters, etc). Cleans up the beer nicely and with some conditioning, will turn out crystal clear beer. This level of filter will also allow you to skip the conditioning phase and have your beer ready to server without spitting up chunks of yeast/hops etc. if you want to have you beer ready as soon as its done fermenting. It also makes it easy to transport your beer because as the beer gets bumped around during transportation, most of the yeast that would get kicked up and put back into suspension has been removed.
I would recommend people new to filtering start at this size filter and move on from there.
1 micron Absolute:
I use this filter for all my light color beers (Ales/Lagers). This filter will remove most all yeast, but not chill haze. I have used this on my APA and IPA's and have not found a significant decrease in hop flavor or aroma using this size filter.
0.45 micron Absolute
I use this on my PIls, Helles, etc. where I want crystal clear beer and want to mechanically remove chill haze. I have not used this level filter on my IPA's or APA's, so I cant comment on whether there is an adverse effect on the flavor profiles I expect to have with these beers.
0.2 Micron
Removes all bacteria. Have not used.
George Fix wrote a bit about the effects of filtering in his book Analysis of Brewing Techniques. He recommended using a 3 micron absolute filter for most all beers and is what you would see most brewpubs/small breweries using. He did find some reduction in color and IBU with filters in the .2 and 1 micron absolute range, although these were very small (1 or 2 degrees SRM and 2-3 IbUs)... not really a big concern with an IPA or APA. I will be trying my 0.45 micron filter on my next batch of my Tasty APA. I will split the batch up and also filter using my 3 micron absolute filter to evaluate any differences. When I get around to it , I will post my results.. hopefully by the end of August.
Good Luck..
I
