Cylindrical conical tank - a tank for fermenting beer , used since the middle of the 20th century as an alternative to the classical fermentation method with separate containers.
Cylinder-conical tanks (or CCTs) have now supplanted open fermentation in most industrial breweries in the world. The reason for this is a significantly larger volume of CCT in comparison with traditional fermentation tanks, and therefore, a higher productivity of the brewery.
Content
CCT device
As the name implies, the CCT consists of a cylinder at the top and a cone at the bottom.
This form, on the one hand, ensures the correct passage of fermentation processes, and on the other hand, makes it possible to separate the settled yeast from beer.
It is believed that CCT should not be higher than 20 meters, since in this case too much pressure will affect the yeast cells, and this will negatively affect the fermentation process. [1] But, nevertheless, the largest breweries are equipped with higher CCT. The rate of beer maturation directly depends on the rate of CO2 formation in it, and the rate of formation of carbon dioxide affects the rate of formation of carbon dioxide. But there are a number of conditions for the relatively standard proportions of the CCT (height: width = 2: 1 or 2.5: 1) - to start the process of accelerated CO2 emission, a minimum volume of 200 - 250 liters is needed. Excellent performance is shown by capacities from 1400 liters. Modern large breweries can use cylindrical-conical tanks made of stainless steel with volumes from 1000 to 3500 hectoliters (1 hectoliter = 100 liters) and it is not possible to infinitely increase the size, since the size of the CCT must be a multiple of the volume of the boiler. The optimal filling time is 10-12 hours, in such an interval, different wort of different brews will be quite uniform and the fermentation process starts almost simultaneously. Given the proportions and height of the wort column, it is pointless to use a CCT with a height of more than 35 meters, since excessive pressure does not accelerate, but rather slows down the process of CO2 emission. When designing, it is necessary to take into account that up to 20% of the total tank volume will go under the foam.
In addition to height, other CCT parameters are also important for beer production, such as the angle of the cone (most often 60-75 °), material (only stainless steel is used in modern brewing), and the location of cooling zones. To create the necessary pressure in the CCT, there is a corresponding shut-off valve with a pressure relief valve (tongue and groove apparatus). For cooling, the CCT has a cooling jacket with ice water or glycol circulating inside. CCT walls are usually well insulated to reduce energy loss.
CCT Fermentation Technology
After cooking, the wort is fed into the bottom center at the same time as yeast is added. Depending on the technology of fermentation, it can go either under pressure or without it. At the end of the main fermentation, the pressure in the CCT accumulates in any case, since it is necessary to ensure the saturation of the beer with carbon dioxide. A feature of the CCT is that all “cold” processes can take place in this tank: the main fermentation, maturation and maturation of beer. [2] The collection of yeast for future use is carried out from the cone of the tank. About 4 weeks are required for the preparedness of bottom-fermented beer in CCT. Top fermented beer can usually be prepared faster. In the case of unfiltered beer, bottling can be carried out directly from the CCT. In other cases, beer is first sent for filtration or separation, and only then for bottling.
Stages of beer fermentation in CCT:
- The first stage, lasting up to 1.5 days, became whiter when a thin layer of white foam is observed along the edges of the surface. At this time, in the wort, yeast intensely buds and multiplies.
- The period of low curls is the stage at which carbon dioxide is intensely secreted and a dense foam is formed. It lasts 2-3 days.
- The maximum fermentation intensity is observed at the stage of high curls (3-4 days). The temperature rises to the highest level, the amount of nutrients and oxygen decreases, which stops the reproduction of yeast. Wort cooling is required.
- Fermentation ends with the formation of a deck for 2 days.
Notes
- ↑ Kunze V. Technology of malt and beer. - 9th ed. - St. Petersburg: Profession, 2009 .-- S. 466-467. - 1031 s. - ISBN 978-5-93913-162-9 .
- ↑ Narcissus L. A short course in brewing. - 1st ed. - St. Petersburg: Profession, 2007 .-- 640 p. - ISBN 978-5-93913-149-0 .