The wort lautering process mainly includes seven processes: hot water laying, feeding, standing, wort reflux, first wort filtration, washing and drainage.
This time, let's talk about the mysteries in the first four processes!
1. Hot water laying
Before pumping the mashed malt into the filter tank, you must first check whether the filter tank is in a normal state. First, clean the filter screen, properly lay it, and press it tightly, then check whether the ploughing knife is in the normal position, check whether the pipe valve connected to the filter tank is in a normal state, and at the same time put the windshield plate and pot door of the filter tank Close it to ensure that the temperature of the incoming mash is as high as possible. After the inspection, hot water at about 78 ° C is pushed in until the filter plate is just removed. The first is to exhaust the air between the filter plate and the bottom of the tank to prevent wheat. The oxidation of the juice, the second is to prevent the air chamber from affecting the filtration, and the third is to preheat the sieve plate and the filtration tank, while supporting the fine particles in the mash, to ensure the normal filtration of wort.
The mashed malt should be pumped into the lauer tank while stirring; at the end of the pump mash, open a few circles of cultivating knives so that the distiller's grains are evenly and evenly distributed to form a better filter layer and improve the quality of wort filtration.
Since it is easy to inhale oxygen during the pouring process, it is better to pump in from the bottom of the filter tank in principle.
3. Stand still
After the mash is pumped into the lauter tank, it needs to stand for about 20 minutes. The wheat husk will quickly settle to form a layer of wheat lees with a thickness of 25 to 40 cm. There are three main filter layers: the bottom layer (composed of coarse and heavy grains), and the main layer ( It is composed of wheat lees, which is the thickest layer and a natural medium for wort filtration) and the upper layer (consisting of light particles such as proteins and fine wheat crumbs separated from the mash, this layer is thinner) The clear first wort is collected in the upper part; standing is an essential process.
The sedimentation speed of the grains in the scum layer is related to the wort concentration, and the sedimentation speed in the thin mash is faster than that in the thick mash. At the same time, it is also affected by temperature. The better the insulation of wort, the looser the layer of wort, and the easier it is to filter the wort. Therefore, it is necessary to pay attention to heat preservation when filtering wort to prevent saccharification and temperature drop. In addition, the better the decomposition during saccharification, the better the sedimentation and separation of the filter layer.
4. Wort reflux
Clear and transparent wort contains a small amount of fatty acids, and the content of fatty acids in cloudy wort will be more than 10 times that of clear wort; if too much cloudy wort enters the filtered wort, it will cause fatty acids in wort Problems such as increased iodine value, poor protein flocculation, and unreasonable wort composition will not only adversely affect the foam and flavor of beer, but also easily cause abnormal fermentation. Therefore, at the beginning of filtration, a turbid wort reflux operation must be performed to improve the clarity of the wort and prevent the above problems from occurring.
After standing still, there are many fine particles accumulated between the sieve plate and the bottom of the tank. The particles passing through the sieve plate are the main substance causing the cloudy wort, so it must be refluxed.
The operation procedure is: first open the valve of the wort outlet pipe at a faster flow rate to make the turbid wort flow out. At this time, carefully pump back to the filter tank (micro equipment or can be connected to the filter tank), depending on the reflux. For the turbidity of wort, adjust the flow rate in a timely manner until the reflux wort is clear; the reflux time is generally about 10min. Then enter the wort filtration stage.
Let's continue talking next time!