How does beer filtration work?

How does beer filtration work?

Beer filtration is one of the most important processes in brewing, which not only affects the taste and quality of the beer but also directly affects the clarity and stability of the final product. Beer filtration not only ensures the clarity of the beer but also improves the quality of the beer by removing impurities and off-flavors. This guide will introduce the detailed beer filtration process, including the preparation before filtration, the selection of the filtration process, and the utilization of filtration equipment.

What is beer filtration?

After the beer has been conditioned, clarified, and stabilized, the beer is filtered to remove residual yeast, precipitated proteins, and polyphenolic cloudy substances. The key role of filtration in beer brewing is to provide stability. Physicochemical stabilization prevents the formation of cloudiness and sedimentation after packaging, while microbiological stabilization eliminates yeast and bacteria that can ruin the beer’s flavor. Filtration is performed at low temperatures (possibly -2 to -1 degrees Celsius, 28-30°F) under counter pressure of carbon dioxide above saturation levels. Filtration can be carried out at various stages of the brewing process, depending on the desired outcome and the type of beer being produced.

Filtration targets various compounds and particles in the beer, including:

  • Yeast cells: yeast is vital to fermentation, but if left in the finished product, it can lead to off flavors or a cloudy appearance.
  • Proteins and polyphenols: these compounds can cause cloudiness and may also lead to undesirable flavors or textures.
  • Microorganisms: Filtration can help remove bacteria and other microorganisms that can damage beer or cause off-flavors.
  • Other particles: Filtration also removes larger particles such as hop fragments, grain particles, or other sediment.

What is beer filtration?

Beer Filtration Process

Preparation after fermentation: After the beer is fermented, it is usually cooled and left to stand for preliminary treatment. The purpose of this stage is to allow solid particles such as yeast and grain residue to settle to the bottom of the liquid so that subsequent filtration can be more effective.

  • Primary filtration: Primary filtration is the first filtration step in the beer brewing process, which mainly removes larger solid particles and suspended matter by physical means.
  • Secondary filtration: Secondary filtration is a filtration step to further improve the clarity and stability of beer. In this stage, finer filters or media are used to remove smaller solid particles and microorganisms, such as residual yeast cells and fine suspended matter.
  • Cold filtration: For beer types that require special clarification, such as pale ale or some advanced craft beers, cold filtration can be performed. This step is designed to further remove fine suspended matter and undissolved solids, so that the beer can achieve higher clarity and taste.

Beer Filtration Types

Deep Filtration

Depth filtration is the introduction of a medium into the beer that binds to large particles suspended in the beer, usually yeast and proteins, but often polyphenols and esters as well. Diatomaceous earth and perlite are the two most common binders used for depth filtration. These media are in powder form and must be handled with care. Winemakers must wear protective gear, including face masks, because these agents can be inhaled and bind to particles in the lungs and other organs. These agents also tend to be expensive.

Surface filtration

Mesh screens are a modern version of coarse cotton cloth and come in a variety of sizes, from large filters of 5 microns and above to smaller filters of 0.5 microns and below. Large filters will trap larger particles but leave behind the yeast and other tannins that are much needed in beer, while small filters will trap even yeast and other small particles but will also remove flavor and aroma.

Single and double-filtering beer

Some brewers will even filter their beer three times to get maximum clarity. This process may involve depth filtration followed by two types of surface filtration. Many mass-produced beers boast triple filtration.

Note: The risk of filtering beer each time is the loss of flavor, aroma, and character.


Most surface filters are in-line cartridge filters that allow you to remove and replace the cartridge when the screen becomes clogged. You can also change the size of the filter as needed. Most craft brewers will recommend that you start with a larger filter and try not to use the smallest filter with a pore size of less than 0.5 microns to avoid removing the essence of the beer.

What equipment is there for beer filtration?

Plate beer filter

Simple filtering device for primary and secondary beer filtration. Cellulose plates of different porosity are used as filter material. The beer is filtered in several cycles – first through the coarse-pore plates, then through the fine-pore plates. The disadvantage of these filters is the time-consuming cleaning and disinfection required after each filtration cycle. The advantage is the low purchase price. Plate filters are recommended for small start-up craft breweries.

Diatomaceous earth beer filter

Candle beer filters with diatomaceous earth are the most commonly used equipment for primary to fine filtration of beer. The filter material is diatomaceous earth, which is a finely ground mixture of prehistoric algae shells – more about diatomaceous earth. The diatomaceous earth is applied to the stainless steel candle filter by controlling the flow of beer through the filter. The advantage of diatomaceous earth filters is that cleaning and disinfection after the filtration process is very easy and fast. After the diatomaceous earth layer is clogged with impurities, it is easily and quickly rinsed off, and the next filtration cycle can be continued immediately. Diatomaceous earth with various porosities can be used for filtration from coarse, medium to fine beer.

Beer Microfiltration Station

The microfiltration station is used for ultra-fine filtration of beer before it is filled into bottles, kegs, beer cans, or cans. The beer is filtered through a very fine membrane, which is placed on a replaceable stainless steel candlestick. By properly selecting and combining microfiltration elements, it is possible to achieve complete microbiological and colloidal stabilization of the beer and achieve its very long drinking period, which is necessary for selling beer to the retail network (especially in bottles and cans). Beer microfiltration completely replaces pasteurization but does not heat the beverage unnecessarily. This gives the beer a better taste and other sensory characteristics than pasteurized beer.


The membrane filter is a new type of beer filtration equipment that uses a microporous filter membrane as a filter medium for filtration. It has the advantages of high filtration accuracy and fast speed, but the equipment cost is high and the filter membrane needs to be cleaned and replaced regularly.

Beer Filtration Process

Filtration process for home brewing

Basic Filtration Options

For those just starting in homebrewing or on a tight budget, there are some cost-effective and user-friendly beer filtration options.

  • Funnel with Fine Mesh Filter: this is one of the easiest and most economical ways to filter your beer. Placing a fine mesh filter over a funnel effectively removes larger particles such as hop residue and some yeast cells, resulting in a clearer beer.
  • Filter Bags: Filter bags, usually made of nylon or polyester, can be used to filter the beer during the transfer process. This method is easy to use and helps remove larger particles from the beer.
  • Plate Filter System: This system utilizes filter plates placed between two plates to filter the beer. Although it requires slightly more investment than the previously mentioned options, the plate filtration system provides higher filtration efficiency and is suitable for small-scale homebrewing operations.

Advanced Filtration Options

More experienced homebrewers or those who want more clarity in their finished product may opt for a more advanced filtration method.

  • Cartridge Filters: These filters come in a variety of pore sizes for different brewing needs and offer higher filtration efficiencies than basic filters. Cartridge filters are usually mounted in a filter housing and can be used with a pump for more efficient filtration. This setup allows for better control of flow rate and pressure to ensure optimal results.
  • Small Commercial Filtration Systems: Some homebrewers may choose to invest in a small commercial filtration system, such as a cross-flow or depth filter, to bring the finished product to a professional-grade clarity. While these systems can be more expensive and require a larger initial investment, they offer superior filtration performance.

Filtration Accessories

In addition to the primary filtration methods, homebrewers have the option of purchasing a variety of accessories to enhance the filtration process.

  • In-line filters: These filters can be added to the transfer line during kegging to capture any residual particles and further enhance the clarity of the finished beer.
  • Oxygenation systems: proper oxygenation during the transfer process is important for yeast health and helps prevent oxidation. Some homebrewers choose to use inline oxygenation systems to introduce oxygen when filtering their beer, ensuring that the yeast has the necessary resources it needs for healthy fermentation.

Häufig gestellte Fragen

Why is beer filtration important?

Filtering beer enhances its visual appeal, flavor, aroma, consistency, and shelf life, ensuring a high-quality product with a pleasant taste.

How is beer filtered?

After fermentation and clarification, beer passes through a filtration system that may involve one or more methods, depending on factors such as the degree of clarity required, the type of beer, and the size of the operation.

Do all beers need to be filtered?

No, not all beers require filtration. Some beers, such as wheat beers and Belgian beers, are traditionally unfiltered and may even look cloudy. However, most commercial beers are filtered at some point to improve clarity and stability.

How do I choose the right beer filtration equipment for my brewery?

Choosing the right filtration equipment depends on several factors, including the size of the brewery, the type of beer being produced, and the budget. The Micet-Gruppe offers a wide range of filtration products including cartridge filters, membrane filters, and filter vessels. Our team of experts can work with you to select the right equipment for your needs and provide training and support to ensure optimal performance.