The brewhouse carries out four beer brewing processes: saccharification, filtration, boiling, and whirlpooling. Saccharification is the process by which enzymes in malt convert starch into sugar. The mash tun is mainly used for the decomposition of malt starch and protein. Therefore, heating and stirring functions are required. Many types of mash tuns are available to adapt to the special needs of craft beer brewing, including single mash tun, mash lauter tank, mash boiling kettle, and mash \ boiling \ whirlpool tank.
Agitator size plays a crucial role in various aspects of the mash tun design. It significantly affects heat transfer, temperature uniformity within the tank, mixing efficiency, and the suspension of solid particles in the liquid. The primary function of the agitator is to effectively suspend the particles in the mash and ensure their even distribution in the wort. This is essential to prevent localized overheating and unwanted interactions during the heating process, as they can adversely affect the quality of both the wort and the resulting beer. To maintain optimal conditions, the speed of the agitator should be adjusted according to the diameter of the tank, with a maximum linear speed of 3m/s. Exceeding this limit would impose shear forces on the mash, leading to undesirable alterations in its composition.
Agitator in a single mash tun
A single mash tun is a common choice when brewing beer on a larger scale. With the expansion of craft beer production, it becomes inevitable to choose a single mash tun. This design is the most frequently used form in brewery brewhouses and is also common in craft beer brewing systems. Due to its special features, the single mash tun is designed for optimal material-water mixing, heat transfer, and solid-liquid suspension. It provides ideal conditions for protein decomposition and starch conversion into fermentable sugars.
At present, the global design of craft beer mashing agitators largely takes inspiration from or follows the agitator of three German brewing equipment giants.
The paddles are designed to be long, wide, and arranged symmetrically. Their blade diameter is approximately 0.85 to 0.90 times the size of the tank. The blades are symmetrical, with the outer edge facing in the opposite direction. This design helps minimize the contact time between the heating medium and the heat transferred by convection. By doing so, it ensures that there are no localized areas of overheating, and that heat transfer is consistent throughout.
This design has two advantages. Firstly, it enhances heat transfer through convection, reducing the possibilities of mush paste formation. Secondly, the use of wide blades allows for operation at lower speeds, thereby reducing the mechanical strain caused by shear forces.
The mixing paddles possess inclined angles and open holes, enabling the enzyme and substrate in the mash to interact effectively. Tiantai agitator is designed with the appropriate inclination angle to make the mash rotate in the tank. This movement favors a well-mixed mash that moves in a rolling cycle from the inside to the outside and from the bottom up, ensuring consistent and uniform temperature throughout the tank (with a temperature difference of less than 0.3 °C between the upper and lower portions). Furthermore, this rotational movement promotes optimal contact between the enzyme and the mash. Additionally, openings in the paddles minimize shear forces and prevent excessive oxygen intake into the mash.
The agitator utilizes frequency conversion adjustment for optimal performance. In practical production, the variation of non-water-soluble substances is often used as a key parameter to gauge shear force. The absolute concentration of non-water-soluble substances largely relies on the design of the agitator. Higher levels of non-water-soluble substances result in an increased shear force on the mash and a faster stirring speed. Therefore, during the saccharification process, it is essential to minimize the stirring speed and decrease the content of non-water-soluble substances. Tiantai's agitator adopts frequency conversion adjustment, which can flexibly control the stirring speed to meet the requirements of the saccharification process. This adaptation facilitates precise regulation of mash convection velocity, preventing excessive shear force. These advantages are particularly evident during high concentration saccharification.
Tiantai agitator in mash tuns is designed to provide gentle agitation without causing surface turbulence. It minimizes shear force and prevents excessive oxygen intake. Additionally, the agitator promotes up-and-down convection of the mash, creating smooth and steady turbulence beneath the liquid surface. This enables optimal contact between the enzymes and materials, reducing reaction time and ensuring your high-quality brewing.
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