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Encyclopedia > Filtered beer
Typical filtered beer
Typical filtered beer

Filtered beer is beer which has been cleaned of significant contact with yeast. Image File history File links Download high resolution version (600x900, 77 KB) Singha beer (Thailand). ... Image File history File links Download high resolution version (600x900, 77 KB) Singha beer (Thailand). ... A glass of beer and different beer bottles. ... Brewers yeast (also known as brewers yeast or brewing yeast) can mean any live yeast used in brewing. ...

Contents

Filtering methods

There are several methods used for clearing yeast from beer.


Some methods involve filtration media such as sheets or candles, while others use a fine powder made of, for example, diatomaceous earth, also called kieselguhr, which is introduced into the beer and recirculated past screens to form a filtration bed. A sample of diatomaceous earth Diatomaceous earth (IPA: , also known as DE, diatomite, diahydro, kieselguhr, kieselgur and Celite) is a naturally occurring, soft, chalk-like sedimentary rock that is easily crumbled into a fine white to off-white powder. ...


Filters range from rough filters that remove much of the yeast and any solids (e.g. hops, grain particles) left in the beer, to filters tight enough to strain color and body from the beer. Normally used filtration ratings are divided into rough, fine and sterile. Rough filtration leaves some cloudiness in the beer, but it is noticeably clearer than unfiltered beer. Fine filtration gives a glass of beer that you could read a newspaper through, with no noticeable cloudiness. Finally, as its name implies, sterile filtration is fine enough that almost all microorganisms in the beer are removed during the filtration process.


Sheet (pad) filters

These filters use pre-made media and are relatively straightforward. The sheets are manufactured to allow only particles smaller than a given size through, and the brewer is free to choose how finely to filter the beer. The sheets are placed into the filtering frame, sterilized (with hot water, for example) and then used to filter the beer. The sheets can be flushed if the filter becomes blocked, and usually the sheets are disposable and are replaced between filtration sessions. Often the sheets contain powdered filtration media to aid in filtration.


It should be kept in mind that pre-made filters have two sides. One with loose holes, and the other with tight holes. Flow goes from the side with loose holes to the side with the tight holes, with the intent that large particles get stuck in the large holes while leaving enough room around the particles and filter medium for smaller particles to go through and get stuck in tighter holes.


Sheets are sold in nominal ratings, and typically 90% of particles larger than the nominal rating are caught by the sheet.


Kieselguhr filters

A mixture of diatomaceous earth and yeast after filtering.
A mixture of diatomaceous earth and yeast after filtering.

Filters that use a powder medium are considerably more complicated to operate, but can filter much more beer before needing to be regenerated. Common media include diatomaceous earth, or kieselguhr, and perlite. Image File history File linksMetadata Download high resolution version (2048x1536, 508 KB) Summary A mixture of diatomaceous earth and yeast. ... Image File history File linksMetadata Download high resolution version (2048x1536, 508 KB) Summary A mixture of diatomaceous earth and yeast. ... A sample of diatomaceous earth Diatomaceous earth (IPA: , also known as DE, diatomite, diahydro, kieselguhr, kieselgur and Celite) is a naturally occurring, soft, chalk-like sedimentary rock that is easily crumbled into a fine white to off-white powder. ... Typical divisions Ascomycota Saccharomycotina (true yeasts) Taphrinomycotina Schizosaccharomycetes (fission yeasts) Basidiomycota Basidiomycotina (club fungi) Urediniomycetes Sporidiales Yeasts are unicellular, eukaryotic microorganisms classified in the kingdom Fungi. ...


Cold filtering

A method that is gaining popularity is cold filtering in which the beer is chilled before or during a sheet filtering process. When beer is chilled the protein molecules tend to clump together and so are easier to filter out.


Lagering

Beer can also be filtered by allowing the yeast to settle to the bottom of the container. The clear or bright beer is then decanted off the sediment. The period spent allowing the beer to settle is known either as lagering or as conditioning. With ale conditioning finings are used to assist in clearing the beer. Decantation is a process for the separation of mixtures, carefully pouring a solution from a container, leaving the precipitate (sediments) in the bottom of the container. ... Finings (the term is a mass noun rather than a plural) is a substance used to aid the clearing of beer, particularly cask ale. ...


Bright beer

The term used by brewers for beer which has been cleaned of yeast is bright beer; such beer is usually held in bright tanks before bottling or additional treatment.


Drop bright

When the yeast in a beer has settled it is said to have dropped bright or fallen bright. This means the beer is clear rather than cloudy.


Pasteurisation

An additional process that is sometimes done to filtered beer is pasteurisation in which the beer is flash heated to kill off any bacteria. Because this process is known to have an adverse effect on the flavour of the beer, the practise is in decline, though some British regional breweries still pasteurise. Pasteurization is the process of heating food for the purpose of killing harmful organisms such as bacteria, viruses, protozoa, molds, and yeasts. ... Regional brewery is a term used in the United Kingdom to describe a long-established brewery that supplied beer to tied pubs in a fixed geographical location such as South Wales, the Midlands or the Isle of Man. ...


Brewery conditioned

In the UK a beer which has been filtered in the brewery is known as brewery conditioned beer. A brewery conditioned beer may just be filtered, or it may also be pasteurised. The term is used to differentiate such beers from those which are still in contact with the yeast which are known as bottle conditioned, cask conditioned or real ale. An alcoholic drink, typically beer, that is bottle-conditioned is one that has been wholly or partially fermented in the bottle from which it is served. ... It has been suggested that Real ale brewing process be merged into this article or section. ... A pint of real ale. ...


See also



 
 

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