Speaking of beer fermenter tank, I believe people who know beer brewing will think of conical tanks. But in fact, during the 1960s, various kinds of fermentation equipment were still popular around the world, such as Asahi pot in Japan, universal pot in the United States, spherical pot in Spain, and so on. These tanks all have their own characteristics, but today they have been largely replaced by conical cans.
After 60's, cylindrical conical bottom fermenter (referred to as conical tank) began to attract the attention of various countries, people made a number of improvements, making the practicality of conical tank greatly improved, and successfully from indoor to outdoor. Outdoor commercial conical fermenter fermentation began in the late 1970s. China's craft beer industry started relatively late, and the selection of fermentation equipment basically adopts small conical cans. However, different designs and different material choices make the experience of use different. Today, we're going to talk about why commercial conical fermenter is so popular around the world, and how to choose the right fermenter for your craft beer!
1. Basic structure and performance of commercial conical fermenter
The conical tank has a 60-90° cone base for easy yeast recovery. The tank body is equipped with cooling jacket, which can meet the requirements of process cooling. Generally, 2-3 sections of cooling jacket are set in the cylinder part of the tank, and one section of cooling jacket is set in the vertebral part of the tank, which is conducive to the recovery and preservation of yeast.
Conical tank is sealed tank, can recover carbon dioxide, can also be carbon dioxide washing; It can be used for fermentation as well as wine storage. In addition, the conical tank is suitable for fermentation above as well as below.
2. The structure and size selection of commercial conical fermenter
If the height of the conical tank is too large, the fermentation liquid flow is strong, and it is easy to form agitation fermentation. Therefore, the liquid level in the tank is an important parameter, which not only affects the composition of fermentation by-products, but also affects the activity and physiological metabolism of yeast. It has been proved in practice that the highest level of wort in commercial conical fermenter is 15 meters. The industry has different views on the diameter to height ratio of conical cans, generally 1:3-1:5 is appropriate.
3. Commercial conical fermenter production material selection
The conical can is originally made of carbon steel, which is easy to rust and must be treated with anticorrosive paint. The fermenter is now made of stainless steel.
The surface finish of conical can is very important. In the rough parts of the tank walls, bacteria have the potential to multiply inside and cause contamination. When the equipment is manufactured, if the use of roller treatment, rough depth up to 0.6-0.8μm; The rough depth of polishing treatment is 0.4-0.5μm, which is the general requirement of the rough depth of conical tank inner wall. The rough depth of electronic polishing is generally 0.3-0.4μm.
4. Commercial conical fermenter insulation material selection
Thermal insulation materials should have low thermal conductivity, low density, low water absorption, and be difficult to burn. The following introduces several commonly used insulation materials: one is polystyrene foam, it is the best insulation material, but the price is higher; Second, the price of amide resin (polyurethane) is cheaper, can be on-site foam spraying, convenient construction, but flammable; Third, expanded perlite, easy to absorb water, insulation performance is poor, large volume, but its price is low, the use of 20-25cm thickness is appropriate. The type and thickness of insulation materials should also consider the local temperature and climate.
In addition, an external protective layer is required outside the thermal insulation material. Generally use aluminum alloy plate or thin stainless steel plate. Corrugated plate is relatively beautiful.
5. Pressure problem of commercial conical fermenter
The fermenter is subjected to a certain amount of pressure. When the temperature and pressure are different, the requirements for the fermenter wall thickness are also different. The pressure of the head and the bottom of the cone should be larger, and the lower part of the cylinder should bear more pressure than the upper part of the cylinder. Where the pressure is high, the compressive strength should be high, and the thickness of the tank wall should be increased accordingly.
