Although we normally try not to filter ours beers we sometimes have no other choice. We’ve found over the years that filtering strips flavor from the beer and also runs the risk of contamination. There are a few different types of home brew filters currently on the market. Smokin Beaver sells the water filter and plate filter types in the shop. For this tutorial we will be talking about the water filter since it is the one that we use (and it can be used as a hop-back if your creative).
Step 1. The first part of filtering actually starts at the boil. Adding irish moss or whirfloc to the last 15 minutes of your boil can be beneficial to the clarity of your beer. These two clarifiers actually bind proteins in the wort making them drop out. Proteins in beer reflect light making it seem hazy. Since the proteins are much larger now they are more likely to get caught in the filter and therefor make your beer clearer.
Step 2. After we transfer from the fermenter to the keg ,we put it in the fridge for cold crashing which makes the proteins and other junk drop to the bottom of the keg. We usually let the keg sit for at least a week before moving onto the filtering process (that is if the beer hasn’t cleared itself by now). At this point we are only adding enough CO2 to remove the oxygen from the keg because any carbonation will make flow through the filter nearly impossible.
Step 3. Now the fun part……..Cleaning. Start by cleaning and sanitizing another keg, tubing and the water filter container. DO NOT sanitize the actual filter!
Step 4. First place filter media inside the container (1, 3 or 5 micron). Hook the ball lock from the “IN” side of the filter to the “OUT” of the full keg. Pressurize the full keg with 2 to 4 psi and allow the beer to flow through the filter and into a waist bucket (We do this first to remove anything that is on the surface of the filter media so that it does not go into the keg). Shut down CO2.
Step 5. Now connect the ball lock from the “OUT” of the filter to the “OUT” of the empty keg. The reason that we are connecting to the “OUT” of the keg is because we want to fill the keg from the bottom which limits its exposure to oxygen. Turn back on the CO2 and start the transfer process through the filter. Keep in mind that since the empty keg is sealed and closed you will need to relieve the pressure every now and then by pulling up on the pressure relief valve. Once transfer is complete place the keg in the fridge, carbonate and enjoy.