Clear Steps to Filtering Homebrew
If you’re thinking, “why would I want to filter my beer?” you’re not alone. Filtering is an excellent technique to implement when homebrewing. Clarity is important to many brewers and drinkers, and is often a mark of quality in beer. It can improve the stability of your beer as well. Some, including myself, would argue that filtering for many classic styles of beer brings clarity to the beer’s appearance, and clarity to the flavor profile. If you’re kegging, adding the equipment is easy. If you’re bottle conditioning, filtering will take more of an investment in equipment. You need to be able to be able to push your beer from one place to another, a task typically performed by a tank of CO2, a regulator, and kegs. Folks without kegging equipment could also get a diaphragm pump to perform this task, be they need to be ready to add a fresh dose of yeast after filtration.
As the haze craze clouds every glass from Portland, Maine to Portland, Oregon it seems a bit of clarity on clarifying may be the last thing on everyone’s mind. Although there are a number of beers that don’t call for crystal clear appearance, the majority of styles do. From amber ales to American porters, Kölsch to Czech Pilsners, clear color is crucial.
So, is clarifying critical to your beer? You may have had a quick gut reaction to the idea of filtering. Maybe, “I don’t filter my beer and I never will” or “I don’t care what my beer looks like” came to mind when you saw this article. At the homebrewing level it’s often discussed as off limits, or taboo, but really it is a generally accepted technique that allows you to make better beer. By removing unwanted material, your beer is more stable and more appealing. Clear beer is possible without filtering, but it’s a great technique to have in your back pocket. I hope we can move past the negative perception and on to better homebrewed beer through a good understanding of filtering! Let’s look at the best wayto filter for great looking and great tasting beer.
THE EYES HAVE IT
When talking about filtering beer, one thing immediately comes to my mind — the perception of a cloudy beer to the drinker. As an avid homebrewer over the past two decades, I’ve handed out a good amount of homebrew. One of the hardest things to overcome is the assumption that a homebrewed beer can’t be as good as a commercial beer. A non-homebrewer makes their mind up before the first sip, when you pour them something like a cloudy Irish red ale. They understand what the beer is supposed to look like, and they’re already tasting that haze with their eyes. Their mind knows something isn’t right, and is already searching out, even before smelling or tasting the beer, what is wrong. The second they give it a sniff, and take a sip, their brain had already decided to look for flaws, or had conceded that they’ll be drinking an inferior product. In other words, your hazy beer never stood a chance.
So, what’s causing the haze in beer? The major culprits are: Yeast, proteins, polyphenols (or tannins), and hop material. A less common haze producer would be pectin, a starch naturally found in fruits and vegetables. This would appear in the quite popular fruit and vegetable beers.
Yeast (or bacteria in the case of sours) is something we can’t avoid in the brewing process, and even in commercial breweries, can end up suspended in the beer post-fermentation. Yeast cell size is fairly large, that’s why we’re able to see it clearly work, and settle to the bottom of our bottle if we naturally condition our beer with yeast. At a cell size of 5-10 microns, yeast can make a beer look downright chunky. Proteins are a bit different. Protein is in beer, and is a factor in flavor and head retention. The proteins that cause haze are of a high molecular weight, and are typically insoluble. Smaller proteins combine with polyphenols (tannins) to form protein-tannin complexes and cause “chill haze.” This occurs when these protein-tannin complex become suspended in solution as the beer is cooled. Typically chill haze goes away above 68 °F (20 °C). The process of cooling creates this turbidity, and particulates precipitate, mostly in a size range of 0.1 microns to 1 micron. This is a fairly small particulate, so individual proteins aren’t seen as globs or chunks, but transparency of the beer is limited.
Chill haze may go away at a high enough temperature, but all other haze-causing agents, including larger proteins, create “permanent haze.” This haze doesn’t go away at any temperature. Typically you see this from larger proteins, 1-10 microns in size. This colloidal solution (a solution with insoluble particles suspended) is mostly made up of these combined proteins and polyphenols. Minimizing either proteins or polyphenols in your beer through proper brewing procedures will help to avoid this haze.
Ways to avoid chill haze and permanent haze include:
• A vigorous boil combined with proper kettle pH will optimize hot break, allowing proteins and polyphenols to coagulate and fall to the bottom of the kettle post-boil.
• Use a kettle fining (like Irish moss).
• Use a chill-proofing agent (PVPP, Polyclar, gelatin, and silica gel).
• Leave trub material in the bottom of the kettle post-boil. Coagulated hot break material and hop material are major causes of haze.
• Use well-modified malt. Under-modified or inconsistent malt may need more help and time in the mash by way of a stepped mash schedule.
• Cold age prior to racking (lagering).
If your beer was clear, but turned cloudy, there are two other common occurrences for haze in a finished product – oxidation and bacteria. Although some bacteria and other contaminants can be removed in filters, others may pass through or be in your bottles or keg. Both oxidation and bacteria can cause haze to appear even after filtering. Be sure to store your beer properly – well carbonated, away from sunlight, and in a clean and sterile keg or bottle.
YOU SHALL NOT PASS
Filtering is great at removing yeast, protein-tannin complexes, and small hop particles. Often hop particles affix themselves to yeast cells. Although filtering removes hop particles, it doesn’t mean it removes hop flavor, aroma or bitterness. In fact, an appropriate filter doesn’t have any significant effect on the bittering of iso-alpha acid, or other acids in solution from hops.
Filtering can struggle with eliminating chill haze. As mentioned earlier, the particles causing chill haze are quite small, and using a filter that would capture these particles is, in essence, capturing your beer. The filter would need to be a solid carbon block, that lets little protein through, or something rated down to eliminating 0.1 microns. These are typically used for filtering water, not beer. Don’t use these to filter beer! A filter below 1 micron, will damage your beer’s flavor and aroma.
One other way to combat these hazes is with coagulants, finings, and clarifiers that can be added to the kettle and/or fermenter. These are ingredients that will either help particles coagulate (helping particles to settle out), or break down those haze-causing agents. A couple common additives in the last 15 minutes of the boil are the kettle coagulants Irish moss and Whirlfloc. Other items like Polyclar (PVPP) or gelatin or Biofine Clear® (silica gel) can be added to the fermenter. These clarifiers are often used in combination with filtering to help reduce haze.
THE FILTER
A proper filter will consist of a filter housing, and the filter media itself. This can cost in the range of $50-$300, depending on the size of the filter and if it includes a pump. This requires something to push the beer through the filter media. Homebrewers often will utilize pressure from a CO2 tank to push the beer through the filter media, but a diaphragm pump will also work for those without a CO2 system. Gravity won’t work as the material needed to filter will be too thick. Any small filter available at your homebrew shop should work for beer. Although many types of filters exist, you’ll typically find them labelled as a “canister filter” or a “plate filter.” The filter media looks different, but has the same effect. Often times plate filters come with a pump, or are meant to be used with a pump. Canister filters are often connected between two kegs and CO2 is applied to push the beer through the filter from one keg to the other. Filters can come as fibrous spun cylinders that would fit a canister, or pressed pads that would fit in the frame of a plate filter. Both styles of filter housing work well. The filter itself typically contains a material like silica, perlite or diatomaceous earth which collects the material as it passes through.
The three most common sized filters for brewers are:
1 Micron: The finest filter you should use. Filtering should result in a very clean, clear beer when finished. This filter will remove most material both large and small but is more likely to clog if there are lots of suspended material present in the beer. Like the other filters, it is not effective for anything less than 1 micron, such as the precursors of chill haze or bacteria.
3 Micron: A happy compromise between a very fine filter, and a coarse filter. May not capture all protein-tannin complex but will capture almost all of the yeast. Recommended if some haze is suspected.
5 Micron: The coarsest filter recommended to remove yeast and haze-causing agents. Anything larger will leave a decent level of yeast behind. This is the most common and popular filter to use on beers with no major haze issues, where the homebrewer just wants additional clarity through yeast removal and a bit of polishing.
A 10 micron filter or higher may be useful as a “pre-filter” if you have serious issues and large particles, prior to running through a second, finer filter. Large pieces of hops, fruit, and spices can cause a filter to clog quickly. Most of these filter materials you can purchase are meant for single-batch use, although some claim that with proper cleaning of the filter, they can be used repeatedly.
A typical filtering homebrewers setup consists of:
• Filter housing – canister or plate.
• Filter material – 1, 3 or 5 micron filter, depending on your goal.
• Tubing in and out with liquid in keg connectors on both ends.
• A clean, empty receiving keg ready to receive/serve beer.
• A full keg connected to a CO2 tank, ready to send beer to the filter.
If you are using a pump, possibly the one included on your plate filter, you can run from fermenter to fermenter, or fermenter to bottling bucket or keg. There is no need to have a closed system like the one above, as you won’t be using gas pressure to move the beer.
Filtering step-by-step (for an in-line filter between two kegs):
1. After fermentation is complete, chill the beer to between 32 °F and 38 °F (0 and 4 °C). This cold crash helps some sediment currently in suspension drop out. The colder, the better!
2. Carbonate the beer (optional, can be done post-filter).
3. Sanitize all of your filtering equipment, including the filter material itself with a no-rinse sanitizer.
4. (Optional) Purge receiving keg with CO2. Attach CO2 to empty keg and add 10 psi of CO2 to closed keg. Open relief valve for 5-10 seconds to purge air while adding CO2.
5. Attach CO2 to the unfiltered beer and set CO2 to around 10 psi. Purge air from the keg by releasing the relief valve for 3-4 seconds, if beer is uncarbonated.
6. Begin assembling the filtering system – connect unfiltered beer keg to the filter (which should have liquid keg disconnects at each end of the tubing), then connect filter to empty serving keg.
7. Open relief valve on serving keg, or attach a gas out disconnect so pressure can escape as filtered beer enters keg.
8. Adjust to flow through filter at a consistent pace, adjusting CO2 as needed. Too fast may clog your filter, too slow may not have enough pressure.
Once complete you should have beautifully filtered beer! Follow the manufacturer’s instructions if the filter can be re-used or should be discarded. If you find your filter has completely stopped, you may need to turn off your CO2, and disconnect the filter to rinse and re-sanitize the filter inside, as you may have asked too much of it. If the filter is visibly disintegrating, discard that filter and start with a fresh filter.
FINAL NOTES ON FILTERING
Filtering is an excellent way to remove yeast, but protein-tannin haze can be avoided through good brewing practices. Filtering creates both shelf stability by eliminating organic material that would otherwise be breaking down in your beer. It also creates an excellent looking product, and beer drinkers drink with their eyes first. All of that material floating in your beer does add flavor to some extent, and that flavor may not be appropriate to your beer. Most beer, outside of New England IPAs, hefeweizens and Belgian witbiers aren’t meant to have protein-causing haze. The color and flavor caused by haze probably aren’t appropriate for your traditional style.
Look for a plate filter with a pump if you aren’t kegging and keep in mind you’ll need to add a small amount of yeast back in if bottle conditioning. If you’re kegging you’ve got a major part of the equipment purchased, and may want to consider a canister filter you can use in-line between two kegs. Filtering is a technique worth using whether it’s for brewing to style, or to help eliminate process issues you may have had.
