For commercial brewers, the filtering stage is the most critical part of the beer brewing process as it is this that helps improve the clarity and flavour of beer.
When it comes to home brewers, however, filtering is uncommon as most lack the right equipment (some even prefer the raw flavour of unfiltered beer).
What exactly does the filtering process do?
Smooth and crystal flavoured beer can be achieved by filtering (It helps extract yeast, tannins and proteins which can make a huge difference to the end product) and is always a good option if you are an intermediate or even an advanced brewer.
Filtering can also be achieved by allowing the beer to precipitate — allowing it to age or via lagering. However, this can take weeks or even months (The right equipment allows you to do it in a matter of minutes).
Commercial breweries prefer to filter their products in a bid to lower their cost and time and keep the production line constant. Apart from the beer being much more presentable, filtering also helps sterilise the brew, improving shelf life and flavour while at the same time speeding up the production time of beer.
Filtering also helps remove smaller impurities – it can separate particles as small as 1 micron or even smaller — which otherwise would still be present even after natural aging. This gives better clarity to the brew.
Many home brewers often ask about how the sediments found at the bottom of the bottle can be eliminated. This can be achieved through a kegging or carbonation system. The yeast is removed through filtering after which priming sugar is added to get flat bottled beer. Filtering involves filtering beer into a keg which then undergoes an artificial carbonation process after which the beer is bottled using a beer gun or a counter-pressure bottle filler.
ABOUT THE FILTER
- Choosing a filter size is the first step of the process. The filter chosen must be fine enough to not alter the flavour of the finished beer while at the same time extracting tannins and yeast cells.
- For the first few times, we recommend using a 1 micron filter size. You can try out other batches using a 0.5 micron filter as well to be certain that the filter is not causing any alternation to the flavour.
- Filter sizes of 5 microns and above can cause yeast to be left behind.
- Commercial brewers even go upto 0.3 microns to eliminate any bacteria thus improving the beer’s shelf life.
- For home brewing though, 0.5 microns is the sweet spot.
- Clogging does occur very often while filtering and thus the size of filter you use does influence it as well. The can be tackled using a two stage filter. Initially you can start by using a 5 micron filter to eliminate larger particles after which a secondary filter of 0.5 micron can be used to tackle smaller particles.
- A two stage filtering process is commonly followed with commercial breweries as well and if you have the budget this can be achieved for home brews too.
- Popular filters used are the inline canister filters with replacable filters. These are preferred for home brewing as they are inexpensive and filter well when high quality cartridges are used.
- Few other filters are also available with large surface areas that are designed in a plate format to reduce clogging. These are often used for wine filtering.
- Household water filters are not recommended as they clog quickly and are extremely slow. It is important that the filter being used is designed to work with beer.
Although filtering does accelerate the aging process of beer, it is recommended not to filter beer early as during the fermentation stages there are plenty of chemical changes, some even occurring during the last phases and also during early stages of aging.
Filtering early can cause this process to stop thus altering the flavour balance. It is always recommended to wait for the fermentation process to complete and allow for at least 2 – 3 weeks in the secondary formation before filtering it to the keg.
The process is fairly simple to execute. Two kegs would be needed and the inline filter is placed between the two kegs. Using CO2 pressure, the beer is transferred to the empty keg via the filter. Replaceable filters cartridges in filters allow for experimenting with various filter sizes. A kegging system is a must for filtering beer. The process involves the flow of beer through the inlet which is forced through the filtering unit and then passed through the exit outlet. The material of the filter is an integral part of the process which is made from polypropylene in styles of wound, spun and pleated.
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What you need
- Other than the filters, you would have to have two kegs placed alongside your brew. One keg would be the receiving keg. Once the brew racks off the fermenter, it would then be passed over to the first receiving keg after which it would run through the filtration system and routed to the second keg.
- CO2 is another must. A 20 pound CO2 tank is ideal along with a regulator set at around 5 psi.
- Other that this equipment, you would obviously need the filter. The one most commonly used is an inline filter, along with a filter cartridge. A 1 micron filter is good enough to get started.
- A tube would have to be connected to the connection hoses which are connected to the ball blocks for coupling to the kegs that connect to each other.
- An auto siphon would be needed to initially get the brew from the fermenter or your secondary fermenter into the initial keg.
- Keep in mind to sanitize all the equipment in use as any unwanted element can mess with the final flavour the brew.
THE PROCESS OF FILTERING
- Take the air lock off the fermenter and place the auto-siphon and begin transferring the brew to the first keg.
- The next step is to hook the CO2 to the second keg and release it out through the release valve to get rid of any oxygen inside the tank.
- Sanitize your hands and get the filter cartridge out of its wrapping and place it into the filter cartridge. There is a purge valve on the top of the filter’s body which we will use to purge air out as liquid is filled.
- Once the filter is purged from any oxygen and the beer is then filtered.
Most commercially available beer is filtered for clarity. Most of the beer available in the United States is filtered and pasteurized. One of the main reasons that beer is filtered is to meet customer expectations. Many customers prefer their beer to be clear and bright in color which isn’t achievable with unfiltered beer as it generally contains some yeast and other brewing particles. Filtering beer also adds stability to the taste of beer and helps create a good amount of foam. Additionally, filtered beer keeps the taste uniform and extends the shelf life of the beer.
To keep beer crystal clear in a bright and sparkling form, commercial brewers use plenty of techniques, fining agents, filtering, etc which can prove elusive to the home brewer. Although many home brewers do filter their brew to achieve a desired color and taste, there are several other factors that need to be factored rather than only depending on the filtering process to yield the desired crystal clear beer. One of the most important elements is cloudiness. Cloudiness comes from either the tannins, proteins or yeast. The type used accordingly has an impact on the end product.
TIPS FOR ACHIEVING BETTER CLARITY
Although protein grains enhance the body of the brew it does have an impact on the clarity of the beer. A choice of two row ales or pale malt extract is recommended for brewing a light beer with beer clarity.
Dark protein malts are added only just enough to create the desired body and color. Using Irish moss at the end of the boil is essential to gain better clarity to finished beer. Irish Moss helps the brew coagulate and quickly fall to the bottom of the brewing pot.
Cooling the brew as quickly as possible is vital to get less tannins and suspended proteins, an essential step to keep the beer lighter.
Another aspect is to choose a yeast high in flocculation as it will clear more quickly than a yeast with a low flocculation rate. The use of thinning agents also helps in improving the clarity of beer by attaching to yeast, tannins and proteins helping it all to precipitate.
Another tip is to store the beer under refrigeration as lower temperatures make it difficult for the yeast, tannins and proteins to remain afloat.
BOTTLING THE BEER
The phase that follows is the bottling process. At this stage, contamination is always a concern and if you do not have all the necessary equipment do not be in a hurry to rush the bottling process.
Before you get started, begin with laying out all your tools on the counter and get a quick inventory to check that everything you need is available.
The tools that are needed are
- A bottle buck that usually comes along with the fermentation kit
- A siphon syringe
- Clear tubes
- A sanitizer
- Racking cane
- Sediment tip
- The proper number of bottles for the liquid
- Bottle capper
- Bottle brush
- Bottle caps
- Stirring spoon and
- Priming sugar
- The bottling bucket first needs to be filled with water
- Add a cap full of plastic clean or similar detergent
- Dump empty beer bottles in to the center and let them fill up. Using a bottle brush give the bottles a good scrub and drain the solution back in to the bucket.
- Rinse the bottles under tap water and leave them upside down to dry.
- Rinse the bottling bucket and refill it with water to give the bottles another rinse with sanitizer.
- Next cut to size the length of clear tube you will need and sanitize it along with the rest of the tools that will come in contact with the beer.
- Meanwhile, add 2-3 cups of boiling water to a sauce pan and bring it to a boil. Once it reaches boiling point, turn the heat off and add a bag of dextrose.
- Next, place the racking cane to the fermentation bucket and clip it to the side of the bucket. The clear tube is also attached.
- With a siphon syringe at the other end of the tube, pull the plunger allowing the beer to flow.
- Once all the beer is racked, it is time to pour the sugar solution.
- Next get a hold of the clear tubing that was cut earlier and push it on to the spigot of the bottling bucket. Grab a bottle and slip the hose into it.
- The spigot it then turned on and the bottle is filled with beer all the way up.
- Once filled, it is then capped and ready for storage.
- Ideally, the beer bottles need to be placed in a box in a storage space where there isn’t any harsh source of light.
- The beer is left in storage for about 7 days. This is called bottle conditioning and is a very important process in home brewing.
- After a few days you will notice carbonation formed in the beer when tipped side to side, let it chill and give it a taste.