The raw materials of beer are barley, brewing water, hops, yeast, starch accessories (corn, rice, barley, wheat, etc. ) and sugar accessories.

barley

Barley suitable for brewing beer is two-rowed or six-rowed barley. Two-rowed barley has high leaching rate and good solubility; Six-rowed barley has high agricultural yield and strong vitality, but the leaching rate is low and the solubility of malt is unstable. The quality requirements of beer barley are: less hull components, high starch content and moderate protein content (9 ~12%); Pale yellow and shiny; The moisture content is lower than13%; The germination rate is above 95%.

Brewing water

Usually soft water is suitable for brewing light beer, and hard water with high carbonate content is suitable for brewing strong beer. The requirements of light beer for water are: colorless, tasteless, transparent, free from floating objects, pure in taste and free from biological pollution; Low hardness; Low iron and manganese content (high content is harmful to the color and taste of beer, which can cause spewing phenomenon); No nitrite.

Hopene

Also known as hops. The beer has unique bitterness and fragrance, and has the ability to preserve and clarify wort. Hops were first used in Germany, and their scientific name was hops. It is a perennial vine herb of Humulus of Cannabis family, dioecious and brewed with female flowers. China has cultivated hops artificially for half a century, starting from the northeast. At present, large hops raw material bases have been established in Xinjiang, Gansu, Inner Mongolia, Heilongjiang, Liaoning and other places. Mature fresh hops are dried and squeezed, and used as a whole hop, or crushed and pressed into granules, and then sealed and packaged, or made into hops extract, and then stored in a low-temperature warehouse. Its effective components are hops resin and hops oil. The consumption of hops per Kl beer is about 1.4 ~ 2.4 kg.

yeast

Yeast is a microorganism used for beer fermentation. Beer yeast can be divided into upper fermentation yeast and lower fermentation yeast. In order to ensure the purity of yeast, the brewery starts with single cell culture for pure culture. In order to avoid the pollution of wild yeast and bacteria, it is necessary to clean and disinfect the brewery strictly.

corn

The properties of corn starch are roughly the same as those of barley starch. However, corn germ contains more oil, which affects the foam retention and flavor of beer. Most corn oil can be removed by removing germ. The fat content of degerminated corn should not exceed 65438 0%. Beer brewed with corn as auxiliary raw material tastes mellow. Corn is the most used auxiliary raw material in the world.

rice

High starch content, high leaching rate and low oil content. But the gelatinization temperature of rice starch is higher than that of corn starch. Beer brewed with rice as auxiliary raw material has elegant color and refreshing taste. Rice is the most used auxiliary raw material in China.

carbohydrate

It is mostly used in sugar-producing areas, and the general dosage is 10 ~ 20% of raw materials. The main types of additives are sucrose, glucose, invert sugar, syrup and so on.

wheat

German white beer uses malt as the main raw material, while Belgian Lambik beer uses wheat as the auxiliary material to brew top fermented beer with local characteristics. Wheat varieties include hard wheat and soft wheat, and soft wheat should be used in beer industry.

Beer production

Beer production can be roughly divided into three main processes: malt manufacturing, beer brewing and beer filling.

Malt manufacturing

There are the following six processes. Barley storage: the newly harvested barley has a dormant period and its germination ability is low, so it should be stored to ripen. Barley selection: impurities are removed by air screening, and the barley is screened into first, second and third grades according to the grain size. Wheat soaking: Soak in water for 2-3 days in a wheat soaking tank, and at the same time, wash with water to remove floating wheat, so that the moisture (wheat soaking degree) of barley reaches 42-48%. Germination: the soaked barley germinates under the condition of controlled temperature and ventilation, forming various substances to dissolve the contents of wheat grains. The suitable germination temperature is 13 ~ 18℃, the germination period is 4 ~ 6 days, and the elongation of root buds is 1 ~ 1.5 times the grain length. The wet malt that grows is called green malt. Baking: the purpose is to reduce moisture and stop the growth and decomposition of green malt for long-term storage; Making malt into substances that give beer color, fragrance and taste; It is easy to remove roots and buds, and the moisture content of roasted malt is 3 ~ 5%. Storage: After baking, the malt is taken out, selected, cooled and stored in a concrete or metal silo.

Brewing

There are five processes. It mainly includes three processes: saccharification, fermentation and wine storage and ripening.

Crushing raw materials: crushing malt and rice with a pulverizer respectively to a degree suitable for saccharification operation. Saccharification: the crushed malt and starch auxiliary materials are mixed with warm water in the gelatinization pot and saccharification pot respectively, and the temperature is adjusted. The saccharifying pot is maintained at a temperature suitable for protein decomposition (45 ~ 52℃) (protein stops). After the fully liquefied mash in the gelatinization pot is put into the saccharification pot, it is maintained at a temperature (62 ~ 70℃) suitable for saccharification (β-starch and α-starch) (saccharification stops) to make malt mash. There are two ways to increase the temperature of mash: leaching and boiling. Protein, saccharification pause time and heating method: according to the nature of beer, raw materials and equipment used, it is decided to filter wort with a filter tank or filter, then boil it in a boiling tank, add hops, adjust the concentration of wort to a suitable level, then enter a rotary sedimentation tank to separate out hot clots, and the clarified wort enters a cooler to cool to 5-8℃. Fermentation: add yeast into the cooled wort, send it to a fermentation tank or a cylindrical conical bottom fermentation tank for fermentation, cool it with a serpentine tube or jacket, and control the temperature. In the subsequent fermentation process, the highest temperature was controlled at 8 ~ 13℃, and the fermentation process was divided into foaming period, high foaming period and low foaming period, and the fermentation lasted for 5 ~ 10 days. The fermented beer is called tender beer, which is bitter, rough and low in CO content, so it is not suitable for drinking. Post-fermentation: In order to make the fresh beer post-mature, it is sent to a wine storage tank or continuously cooled to about 0℃ in a cylindrical conical bottom fermentor, and the pressure in the tank is adjusted to dissolve the CO in the beer. The storage period of wine is 65438 0 ~ 2 months, during which the remaining yeast, cold coagulum, etc. Gradually precipitate, the beer is gradually clarified, CO is saturated in the wine, and the taste is mellow, which is suitable for drinking. Filtering: In order to make the beer clear and transparent and become a commodity, the beer is clarified and filtered at-1℃. The requirements for filtration are: large amount of filtration, good quality, less loss of wine and CO, and no influence on the flavor of wine. The filtration methods include diatomite filtration, cardboard filtration and microporous membrane filtration.

Beer filling

Filling is the last process of beer production, which has a direct impact on maintaining the quality of beer and giving it the appearance and image. The beer after filling should meet the hygienic standard, so as to minimize the loss of CO and the air content in the container.

Barrel: The barrel is made of aluminum or stainless steel, and its capacity is 15, 20, 25, 30 and 50l. Among them, 30l is a common specification. Barreled beer is generally draft beer without high temperature disinfection. Draft beer has good taste and low cost, but its shelf life is not long, so it is suitable for local sales.

Bottle: In order to maintain the quality of beer and reduce the influence of ultraviolet rays, brown or dark green glass bottles are generally used. Empty bottles are soaked in a bottle soaking tank (alkali solution 2 ~ 5%, 40 ~ 70℃), then washed by a bottle washer, filled with beer by a filling machine, and capped by a capping machine. After pasteurization by a sterilizer, it can be packaged and delivered from the factory after passing the inspection.

Canning: Canned beer began in America 1935. In the second world war, it developed rapidly because of military supplies. After the war, after a series of technical transformation, the demand gradually increased. 1966, the ratio of bottled and canned in the United States is 52: 46. The tank body is made of aluminum or copper. Canned beer is light in weight and easy to transport, carry and open bottles for drinking, so it is very popular with consumers and develops rapidly.

PET (polyethylene terephthalate) plastic bottles: they have been put on the market since 1980, and the number has increased year by year. Its advantages are high transparency, light weight, resealable after opening and reasonable price. The main disadvantage is poor gas retention, and during storage, CO gradually decreases. Adding coating can improve gas retention, but the storage time should not be too long. PET bottles can't be vacuumized or pasteurized in advance, and special filling procedures are needed to avoid air entry and bacterial contamination.

New technology of beer production

There are seven main types. Thick mash fermentation: 1967 began to be used in production. It is a method of fermenting wort with high concentration and then diluting it into finished beer with specified concentration. The output can be increased without increasing or increasing production equipment. The concentration of wort is generally around 16 P for rapid fermentation: by controlling fermentation conditions, on the basis of maintaining the original flavor, the fermentation cycle is shortened, the utilization rate of equipment is improved and the yield is increased. The control conditions of rapid fermentation process are: increasing the temperature at a certain stage of fermentation process; Increase the inoculation amount of yeast; Stir. Continuous Fermentation: There was a scheme of beer continuous fermentation in 1906, but it was not industrialized until 1967. The main applicant countries are New Zealand, Britain and so on. The popularization of beer continuous fermentation technology is limited by the problems of easy variation of strains, pollution of miscellaneous bacteria and beer flavor. Study on beer production by immobilized yeast: The research began in 1970s, aiming at greatly shortening the fermentation period. In essence, it overcomes the problems of strain variation and miscellaneous bacteria pollution, and it is a faster continuous fermentation process. The results showed that the pre-fermentation was shortened from 5 ~ 10 day in the traditional method to 1 day, and it could run continuously and stably for 3 months. Cylindrical conical open-pit fermentor: It has been used in production since 1966. Its main advantages are: shortening fermentation period, saving investment, easy recovery of CO and yeast, and being beneficial to automatic control. At present, it is very common that the volume of a single tank is 600Kl, and the material is generally stainless steel. Development of draft beer: With the success of sterilization, filtration and aseptic packaging technology, draft beer which can be preserved for a long time without pasteurization has been developed since 1970s. Because it tastes good, it is very popular with consumers. At present, draft beer accounts for 50% of the total beer production in some countries. Development of low-alcohol and non-alcohol beer: a cool drink for car drivers, women, children and the elderly. It is characterized by low alcohol content. The alcohol content of alcohol-free beer is generally 0.5 ~ 1%, which is rich in foam, light and refreshing in taste, and has a good hops flavor, maintaining the characteristics of beer.