In the previous article, ACE Craft’s engineer explained in detail the malt grist case, material-water mixer, mash tun, and their respective heating methods and process selection. Now, let’s continue our discussion, shall we?
How to Choose Cost-Effective Craft Beer Equipment – Lauter Area
When it comes to the lauter area, bigger is not necessarily better. It should correspond to the concentration of beer you want to make. The higher the concentration, the larger the filtration area needs to be. This is because there is an upper limit to the weight per unit area of the sieve plate and the thickness of the spent grain layer. If the spent grains are too thick, lautering becomes difficult and time-consuming. This not only increases the time cost but also has a negative impact on beer quality.
Originally, filtration is meant to separate the spent grains as quickly as possible while ensuring the clarity of the wort. Prolonged contact between the wort and spent grains can release substances that are detrimental to the beer. Therefore, if you have specific concentration requirements, make sure to communicate them in advance so that the lauter tun diameter can be calculated and adjusted accordingly during the design stage.
The sieve plate style can be divided into two types: welding and milling. The welding type is made up of two layers of stainless steel strips, cross-welded in a piezoresistive pattern with a gap of 0.9mm. This forms a triangular section with a narrow upper width and a wider lower width. Except for the upper layer of stainless steel strips, all other areas are lauterable areas.
The milled sieve plate is created by milling rows of triangular cross-section grooves with a width of 0.7mm on a stainless steel plate using an alloy milling cutter. To increase the load-bearing strength, the center is hollowed out, creating a larger gap. The whole plate is then processed and polished.
- Advantages: The milling screen offers a higher opening rate compared to the welding screen. However, this comes with a trade-off. If you prioritize aesthetics, you must accept a lower opening rate. If practicality is more important, it may not look as visually appealing.
- Disadvantages: The welding sieve plate can be relatively uneven due to the heating process. Although efforts are made to level it later on, it still cannot match the milled sieve plate in terms of evenness, and its appearance may be slightly rough.
In terms of cleaning efficiency under the sieve plate, having a cone angle is generally preferred. However, if the feeding volume is not too large (below 2000L), this is an optional feature. When the sieve plate is flushed, the particulates will flow down the cone towards the sewage outlet instead of moving from one position to another, like with a flat bottom. A flat bottom, on the other hand, only allows part of the particulates to fall into the distributed sewage outlet. But in terms of support strength, a flat bottom is preferable.
Sieve Plate Installation
The ideal scenario is to have one bolt to fix the sieve plate, making it quick and easy to disassemble and assemble. Some brewers have to disassemble and assemble the sieve plate every day, which can be time-consuming and labor-intensive. There are two common types of sieve plate installation:
- Reinforced type: This method involves welding a vertical plate under the sieve plate, usually a small 4x40mm section. It is directly welded onto the screen plate, which can affect its appearance and increase its weight. Although there are no visible bolts on the surface, the weight alone can be burdensome.
- Bracket type: This method uses L or ⼕-shaped stainless steel to weld a square plane vertically and horizontally, with column support below. The sieve plate is then fixed onto it with more than ten bolts. While the sieve plate is lightweight when taken out, disassembling it can be difficult.
There are different types of raking blades based on processing technology. They can be categorized as follows:
- Welding type: This type does not have any machining traces. It is made up entirely of round tubes, square tubes, and stainless steel sheets. The blade triangles are laser-cut and there are no couplings. The shaft of the reducer is directly fixed with bolts, and the fixed flange of the reducer is cut from a steel plate.
- Semi-machined type: This type includes a coupling, but the shaft is polished using a thick-walled round tube. The raking blade is laser-cut, and there is a half sleeve between the raking blade shaft and the arm, making it detachable. Each blade is directly welded to the cross arm, and the fixed flange of the reducer is machined.
- Machining type: In this type, the flanges, shafts, couplings, and half sleeves are all machined. The blades are fixed on the cross arm using bolts. Some customers have designed the joints to be round to prevent material storage and facilitate cleaning. This design is both aesthetically pleasing and practical.
For small equipment that doesn’t require raking during lautering, raking speed is not a major concern. However, for slightly larger lauter tuns, especially those with continuous feeding requirements, it is important to control the speed of the reducer at around 0.25-0.4 rpm to avoid affecting wort turbidity during filtration. This requires a larger reduction ratio.
Raking Blade Lift
When lautering becomes difficult, ploughing the wort can help loosen it and improve lautering speed. However, it is important not to plough the entire grain layer together, as this will inevitably affect wort turbidity. Instead, ploughing should be carried out from top to bottom. This method is generally used for equipment above 2T, and the height of the outrigger will increase as it lifts and lowers. If your venue has limited height, you may want to consider alternatives such as reversed grain discharge or chain type grain discharge.
Grain Discharge Methods
There are two common methods of grain discharge: side grain discharge and bottom grain discharge. Side grain discharge without lifting is very convenient and practical (for equipment below 2T). With the use of a scraper, grain discharge is made even more convenient. The grain discharge flaps must be the same height as the sieve plate to ensure proper grain discharge. Bottom grain discharge is generally used with a screw conveyor, which is more common in lauter tuns with larger volumes.
Due to the limited number of words available, I can only provide a brief and concise description. It seems that there is a need for a Part 3 to cover the remaining details. Nevertheless, remember that the key to a lauter tun is quick lautering, clear wort, and clean grain discharge. Other considerations are relatively secondary.
Plan Your Craft Brewery
Now that you know how to choose cost-effective craft beer equipment, you can turn your dreams into reality by opening your own craft brewery. However, starting and managing a craft brewery can be challenging. If you are new to the craft beer industry, you can contact us for professional solutions. We offer turnkey beer equipment solutions and can help you with design, manufacturing, and customized solutions for expanding your brewery.