Views:153 Author:Auril Publish Time: 2021-01-08 Origin:Site
After the beer mashing process is over, the decomposition of the high-molecular substances in the wort has been completed, and the soluble and insoluble substances in the saccharified mash should be separated quickly to obtain a clear wort.
The wort filtration process can be roughly divided into two stages:
First wort filtration: the wort obtained by filtering the mash with the spent grain as the filter layer is called the first wort.
Washing the spent grains: Wash the soluble extracts in the spent grains with hot water, and the obtained wort is the second stage wort or the wash spent grains wort.
The requirement of wort filtration is to quickly and thoroughly separate the soluble substances in the mash, minimize the barley husk polyphenols, pigments, bitter substances that affect the beer flavor, and the high molecular proteins, fats and other substances in the malt into the wort to ensure that the wort has good taste and high clarity.
The lautering tank is the wort filtering equipment used in most beer breweries.
The basic structure of the lautering tank:
The lauter tank is generally made of stainless steel 304 with an insulation layer. To reduce oxidation, the mash is introduced from the bottom.
At the bottom of the sieve plate, a number of cleaning nozzles are evenly installed. After the filtration is completed, edible high-pressure water is used to rinse the bottom of the sieve plate.
Sieve plate: The distance between the sieve plate and the bottom of the tank is 20mm. Regardless of the type of sieve plate, the opening rate is generally 10%-30%. The opening width is 0.5～0.7mm. The latest research shows that the opening rate of the sieve plate reaches 10% to 12%, because the more important factor that affects the filtration rate of the wort is the thickness of the spent grain layer.
Raker: Raker plays an important role in accelerating the filtration rate of wort and improving the quality of wort. In most cases, the first wort has been filtered and the spent grains have been squeezed tightly together. At this time, the resistance of the spent grains increases and the flow speed of wort decreases. Then, the spent grain layer must be loosened with the help of a raker to reduce the resistance of the spent grain and accelerate the filtration of the wort. In the process of washing the spent grain, the raker can improve the contact between the water and the spent grains, and add new wort channels to make the wort filter faster and wash the spent grains more thoroughly.
Complete beer brewery equipment mashing system
The using method of raker
The requirement for the use of the raker is to cut the grain layer without destroying the formed filter layer. The speed of the raker can be adjusted steplessly. At the same time, the raker can divide and loosen the grain layer at different heights. The water flows into the grain layer along the shear line, and the adjacent part is washed out. For example, in order to reduce the resistance of the grains when the first wort is filtered, the raker can be rotated about 1~2cm above the filter plate. When the second wort is filtered, properly rotate the raker to make the resistance of the spent grains within a certain range to ensure that the spent grain washing water evenly penetrates into the spent grains layer.
Technical requirements of modern lauter tanks
Mash feed in at the bottom to reduce dissolved oxygen
Screen gap: 0.5-0.7mm
Free circulation area of sieve plate: 15%
The refluxed turbid wort enters under the wort liquid surface to reduce dissolved oxygen
The number of mixing blades of the raker: 2-2.25/m2
Speed control of rakerand wort pump: frequency conversion adjustment
Load of sieve plate for dipping and humidifying crushed malt : 250kg/m2, fast filtration, no stratification of grains.
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