After fermentation or post-treatment of mature beer, its residual yeast and protein coagulants are deposited at the bottom of the beer tank, and a small amount is still suspended in the beer. These substances will precipitate from the beer during the subsequent storage period, causing the beer to become turbid. Therefore, it must be removed through the filtration process.
Purpose of beer filtration:
- Remove turbid substances, such as protein, protein-tannin complex, polyphenols, glucan, and some paste substances.
- Remove some microorganisms, such as cultured yeast, wild yeast, bacteria, etc.
- Isolate oxygen.
- Eliminate the influence of iron ions, calcium ions, and aluminum ions.
- Reduce the influence of mechanical effects on beer (easy to cause the formation of colloids).
- Meet the requirements of product purity, such as no residual cleaning agents and sterilizers.
- Ensure that the original wort concentration of the product is qualified.
- Maintain the foam performance and bitterness value of beer.
- Improve the sensory quality of beer and enhance clarity.
Beer filtration is a physical process that uses filter media to separate and remove the tiny particles suspended in beer from the beer liquid, making the beer clear and transparent without suspended matter. It is a very important production process in the beer production process, which is related to the appearance and taste of beer as well as biological stability and non-biological stability. After filtration, the appearance of beer is clear, transparent, and shiny, making it more attractive; at the same time, it can give beer good biological stability and non-biological stability, so that it will not change in appearance at least during the shelf life, thus ensuring the perfect appearance quality of beer.
In the brewery, because the post-fermented mature beer contains a large amount of yeast, the beer is very turbid. Therefore, it is generally necessary to perform coarse filtration first and then fine filtration. Breweries can also choose to use several filtration methods in combination according to product quality requirements and cost considerations, and the effect is better. For beer filtration, the most commonly used equipment now are diatomaceous earth filter, paperboard filter and sterile membrane filter. A diatomaceous earth filter is used as coarse beer filtration, paperboard filter is used as fine beer filtration, and sterile membrane filtration is mainly used to produce pure draft beer.
