You only get one chance to make a first impression, and unless you’ve brewed some version of wheat beer or a New England-style IPA, a glass full of haze will cloud people’s perception. It’s not fair to be judged by your beer’s appearance, but those visual cues can affect how it tastes. Rather than hide it in a red plastic cup, let’s talk about how filtering can give your beer a makeover. We’ve covered using finings to clear your beer, and that will make a big difference, but filtering takes it a step further. If you only bottle condition your beers, this isn’t worthwhile, but if you already have a keg setup, it’s an easy addition to your process.
Understanding the Problem
The most common causes of cloudy beer are hazes formed of proteins and tannins along with having lots of yeast in suspension. Filtering handles both of these readily.
Starch haze is another possibility, which arises if your mash didn’t finish conversion. If this is a regular problem for you, you should focus on improving your mash process and consider using an iodine test to check for conversion. On the other hand, if you’re only seeing it with wheat or rye beers, that cloudiness comes with the territory.
Finally, a bacterial infection can also present a cloudy beer, but the appearance is less of an issue than the flavor. Replace your plastic gear like hoses and buckets, and focus on improving your sanitation.
Choosing a Filter
While there are many types of filter setups, your best bet is a simple 10” cartridge canister filter. These are ubiquitous and replacement filters are easy to find. While the cartridges themselves are standard, there are still choices to be made. Some are only intended for a single use, while others can be reused with the right care. Additionally, the cartridges are graded by the size of the smallest particle they’ll block. As a homebrewer, your sweet spot is around 1.0 micron. If you go any finer than 0.5 micron, you’ll lose some of the flavor and mouthfeel, while anything above 5 microns won’t pull out the yeast.
If you buy a setup from a homebrew shop, the cartridge should already be the right grade for filtering your beer and the filter housing might come with keg connectors. I’d recommend this because many brew shops have competitive prices and you can be confident you have the right thing. Alternatively, you can shop for a 10” water filter system and buy the appropriate connectors and cartridge.
A filter works best if you give it a boost. Keep using finings such as Irish moss, and when fermentation is complete, cold crash your beer to remove excess yeast. These steps will extend the life of your cartridge. The filter will sit inline between two kegs. Your beer goes into the first one, then you’ll use CO2 to push the beer through the filter into the second keg. Let’s take a closer look at how this works.
Sanitation is key. Sanitize both kegs, the filter housing and cartridge, and the connecting hoses. If you’re using a new cartridge that’s sealed and sanitized, you can use it directly, although it’s a good idea to flush it for a few minutes by running water through it.
Before you start, purge both kegs with CO2 to reduce the risk of oxidation.Fill the first keg, then assemble the flow chain. The liquid line of your full keg goes to the filter’s intake side, the outlet side of the filter runs to the liquid line of the empty keg. Do not carbonate the beer first. Pushing carbonated beer through a filter requires more attention and can be a foamy mess.
Attach CO2 to the gas inlet of the first keg. Start with low pressure (3-5 PSI), and slowly raise it to keep the flow running. If your second keg has a manual pressure relief valve, open it. Otherwise, attach an open line to the gas inlet of the second keg. This keeps pressure from building up and assures the continued flow of beer through the filter.
Once the beer is transferred to the second keg, it’s ready to disconnect and carbonate.
Clean the first keg and filter. This includes back flushing the system. Rinse the keg and fill it with some sanitizer. Connect the liquid line to the outlet side of the filter (the reverse of your earlier chain). Remove the quick connect from the filter’s inlet hose. Now, apply a low CO2 pressure to the keg to push the sanitizer back through the filter to clean it.
Adding filtration to your brewery is a minor expense (under $50), but that investment will let you show off your brewing brilliance.