Lautering
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After mashing, wort (the liquid portion containing extract) must be separated from the spent grains in order to continue. This process is called lautering.[1][2]
The first runnings are generally returned to the top of the mash and the wort is recycled until it is completely clear and "runs bright".[3] Turbid worts should be clarified as soon as possible in the production process and certainly before they reach the fermentation vessels (Maule, 1986). In general, more turbid worts carry more lipids and techniques are usually adopted to minimize turbidity and the amounts of lipid remaining in the wort, even though their presence can increase the fermentation rate. Thus the wort is recirculated through the filter bed until it "runs bright". More lipids are also removed at later stages of the brewing process, for instance, during wort boiling and clarification, but it is sound practice to obtain the sweet worts as bright as possible. Using a traditional mash/lauter tun minimizes the amount of lipids in the wort.
Lautering speed is increased by keeping the malt husk as intact as possible during milling to give the mash bed a more "open" structure.[3] Flow speed is also increased by Low oxygen brewing, maintaining adequate levels of calcium ions (particularly in thick mashes), using well-modified malt, and collecting wort at elevated temperatures.
Lautering temperature is important. The viscosity of the liquid decreases as temperature increases, allowing lautering to proceed more rapidly. However, it's also important that the temperature doesn't get too high. Undissolved starch may be washed out of the grain during sparging, which may cause haze if it isn't converted. Therefore it's important for alpha-amylase to remain active during lautering, and so the temperature must not exceed 76-78°C.[1][2]
Two basic lautering methods exist for home brewers, and they are not mutually exclusive:
- A traditional false bottom or screen in the mash tun
- A porous bag holding the grains (brew in a bag, called BIAB)
Both of these methods are very effective and easy to use. However, removing the grain from the wort with a BIAB tends to introduce more often, and therefore a system with a false bottom is preferred for brewers wishing to avoid oxidation. In other words, aeration of the wort should be avoided.[2] Brewing systems are discussed separately.
The initial wort drained from the mash vessel is called "first wort".
Wort running into the kettle can range from clear to very hazy (turbid). The substances causing haze are fatty acids and proteins that are required by the yeast for growth. Turbid wort therefore often leads to a shorter fermentation time by 1 to 2 days. A more turbid wort has also been shown to produce beer that is somewhat fresher, fuller, more palatable, more floral, pure, softer, more pleasant, with a more clean bitterness, and generally has more character. A disadvantage however is that beers with more turbid are much more susceptible to oxidation (decreased flavor stability).[1] Therefore the ideal haze value during lautering with no cold break removal is 20 EBC. Clear worts impair fermentation and therefore reduce the quality of the beer. Moderate haze in conjunction with optional yeast treatment is therefore ideal.
Wort run off should be as clear as possible during lautering so that no particles that could disintegrate further during wort boiling and only small amounts of long-chain fatty acids (which destroy foam and contribute to staling) can get into the kettle.
- Influence of Lauter Turbidity on Wort Composition, Fermentation Performance and Beer Quality – A Review
- https://www.tandfonline.com/doi/abs/10.1094/ASBCJ-64-0016?journalCode=ujbc20 same?
- Dextrin as the main turbidity components in wort produced from major malting barley cultivars of Jiangsu province in China
- Turbidity potentials of single long‐chain fatty acids and gelatinised starch in synthetic lautering wort
- https://www.agraria.com.br/extranet_2016/uploads/AgromalteArquivo/cor_do_mosto_e_turbidez_-_ing.pdf
- https://blog.hannainst.com/beer_haze_turbidity
- https://books.google.com/books?id=gcJQAwAAQBAJ&pg=PA219&lpg=PA219&dq=%22wort%22+turbidity&source=bl&ots=u0eopDpnJo&sig=ACfU3U3dvYS362tTHf6Ff-tpaVCvnoyLhg&hl=en&sa=X&ved=2ahUKEwiUjLuy2K_qAhW0knIEHXisBRY4FBDoATAFegQIBhAB#v=onepage&q=%22wort%22%20turbidity&f=false
- https://books.google.com/books?id=Ut3LBQAAQBAJ&pg=PA467&lpg=PA467&dq=%22wort%22+turbidity&source=bl&ots=qs90JphsR9&sig=ACfU3U1ObaxhuK9eHWdlsf_GLlcTJC6CTg&hl=en&sa=X&ved=2ahUKEwiUjLuy2K_qAhW0knIEHXisBRY4FBDoATAHegQICBAB#v=onepage&q=%22wort%22%20turbidity&f=false
- https://bsgcraftbrewing.com/Resources%255CCraftBrewing%255CPDFs%255CBrewing_Processes_and_Techniques/WortandBeerFiningManual.pdf
- https://www.homebrewtalk.com/threads/importance-of-wort-clarity-after-mash.671365/
References
- ↑ a b c Kunze W. Wort production. In: Hendel O, ed. Technology Brewing & Malting. 6th ed. VBL Berlin; 2019.
- ↑ a b c Krottenthaler M, Back W, Zarnkow M. Wort production. In: Esslinger HM, ed. Handbook of Brewing: Processes, Technology, Markets. Weinheim, Germany: Wiley-VCH Verlag GmbH & Co. KGaA; 2009.
- ↑ a b Briggs DE, Boulton CA, Brookes PA, Stevens R. Brewing Science and Practice. Woodhead Publishing Limited and CRC Press LLC; 2004.