With the development of technology, the biological stability of beer has been greatly improved. Still, the flavor stability and freshness of beer have not been improved to the satisfaction of consumers. Therefore, how to extend the flavor stability and freshness of beer will be an important issue in the brewing industry. There are many factors that affect the freshness of beer, and numerous documents describe the relevant factors in each link from raw materials to products, sales and storage. There’s an argument to be made that the smartest way to improve the freshness of beer is to improve packaging technology. At present, most domestic manufacturers use tunnel spray lymphatic sterilization to produce bottled cooked beer, which is very detrimental to the flavor stability and freshness control of the beer, and the shelf life is short; using membrane filtration technology to produce pure draft beer better solves the problem The shelf life of beer is a problem, but it has shortcomings such as weak beer taste, gradual attenuation of foam, and high operating costs. Instant sterilization technology was first used in the beer industry in the production of barreled fresh beer. The products produced have long shelf life and low production and operating costs. Low, stable physical and chemical indicators and other advantages. However, there have been no reports on the large-scale application of instant sterilization technology in bottled beer production.
- Comparison of major beer sterilization technologies
In order to ensure the biological stability of beer, various methods must be used to kill the yeast and bacteria present in the beer. Pasteurization technology, membrane filtration technology, etc. can all achieve their goals, but they have different negative effects on beer. Pasteurization is the process of heating beer, using heat to kill or inhibit yeast and bacteria that can survive in filtered, clarified beer. There are two methods of pasteurization: instant sterilization and tunnel spray sterilization. Instant sterilization is to heat the beer to 70 degrees Celsius and hold it for 15-25 seconds; tunnel spray sterilization is to heat the beer to 60 degrees Celsius and hold it for a time. Membrane filtration technology allows the beer to flow through an ultra-microfiltration membrane that can intercept all microorganisms in the beer, making the beer sterile.
- The impact of different sterilization methods on the shelf life of beer
As storage time increases, perceptible flavor defects in beer increase. A large amount of experience has proven that the aging smell of beer is the result of the reaction between dissolved oxygen in beer and about 600 flavor substances in beer. The deeper the reaction, the more prominent the aging smell will be. Most factories have controlled the dissolved oxygen in beer to a very low level, but the aging smell of beer still occurs quickly, and the shelf life is not as long as expected. The root cause is that the temperature and time closely related to the oxidation reaction are not well controlled. control. Whenever the temperature increases by 10 degrees Celsius, the oxidation reaction rate will increase by 2-3 times. Affects the progress of oxidation reaction
Another factor is time. At the same temperature, the longer the time, the greater the degree of oxidation.
In order to comprehensively measure the influence of temperature and time, a concept of heat load can be introduced and the heat load can be expressed as: RQ=f(T,t). Among them, RQ represents the heat load, T represents the temperature influence factor, and t represents the time influence factor. The length of the shelf life is closely related to the size of the heat load. The greater the heat load, the greater the degree of oxidation, and the shorter the shelf life. Tunnel spray lymphocytic sterilization produces the greatest RQ. RQ consists of two aspects: one is the heat load generated by maintaining 60 ℃ for about 10 minutes, and the other is the heat load generated by the beer naturally lowering from 35 ℃ to room temperature for about 12 hours after leaving the sterilizer; the heat load generated by instant pasteurization RQ is second. Although the temperature is higher than 60 ℃, the holding time is only 10~20 s; the membrane filtration method basically has no heat load. Therefore, the beer produced by membrane filtration technology has the longest shelf life, followed by the beer produced by instant pasteurization, and the beer produced by tunnel spray lymphatic sterilization has the shortest shelf life.
- Comprehensive comparison of beer production under different sterilization methods
Although the beer produced by membrane filtration technology has a long shelf life, it also has many shortcomings. The ultra-micro filter that can intercept all microorganisms can also intercept macromolecular substances such as proteins, dextrins, and melanoidins, but these substances can affect the taste, holding properties, color, and partial flavor of beer; the beer foam produced by membrane filtration The problem has always been a technical problem that has plagued the beer industry, affecting the taste and appearance of beer; the filter element is expensive and needs to be replaced regularly, and the packaging process uses highly demanding aseptic cold filling technology, which has limited it to a certain extent. application of this technology.
The advantage of tunnel spray lymphatic sterilization for beer production is the low requirements for brewing and packaging. However, the production equipment occupies a large area and the production cost is high, especially the sterilization time is long and the freshness period of the beer is short.
Instant pasteurization equipment is simple, the overall production cost and energy consumption are the lowest, and the beer has a longer shelf life. However, it has high hygiene requirements for packaging, and aseptic cold filling technology must be used. Generally speaking, the use of instant sterilization technology in the production of bottled beer has many advantages such as long shelf life, low cost, “good feeling, good foam, etc., and has attracted attention.” In the next few years, instant beer sterilization technology is likely to become a new technology in beer packaging and be widely used.