Alcohol made from sweet potato

Alcohol, also known as ethanol, is an important chemical raw material, which can produce a variety of organic reagents and solvents, as well as dyes, paints, pharmaceuticals, spices, synthetic materials, detergents and so on.

1. Technological process: koji-making mother wine-cooking gelatinization-saccharification fermentation-distillation

2. Key points of process operation:

① koji making: most of the saccharifying agents used in this process are cultured in solid medium. Adding 5%-10% grain bran or fine rice bran as culture medium and cultivating Aspergillus Niger or Aspergillus flavus as saccharifying agent, called bran koji method. Aspergillus by bran koji method is generally expanded through several stages, such as test tube culture, petri dish culture, seed koji production and koji making, until it meets the needs of production.

Test tube culture: commonly used Aspergillus Niger strains (such as Aspergillus Niger Qingyan 2) are provided by special research units. There are many kinds of culture media used in test tube culture, and millet medium can be used. The millet medium was divided into test tubes for cleaning and sterilization, each tube was about 10 milliliters, steamed and sterilized three times at intervals of 1 day and night each time, steaming for 1 hour. After the last sterilization, the test tube was placed obliquely overnight and a small amount of Aspergillus Niger was inoculated with an inoculation needle. It multiplied vigorously after 5-7 days at a temperature of 30-32 degrees Celsius. After passing the inspection, it can be used to expand the culture.

Petri dish culture: can be carried out in a petri dish or flask. The culture medium can be made of 5%-10% rice bran or fine rice bran, soaked in 1-1.2 times water for 2 hours, steamed in a pot for 30 minutes and 40 minutes, respectively, in a sterilized petri dish or flask with a thickness of 0.2-0.3 cm. Continue steaming for 30 minutes to form the culture medium. When the culture medium is cold to less than 40 degrees Celsius, a small amount of Aspergillus Niger cultured in test tube is connected with an inoculation needle in an aseptic room, fully stirred, put into a thermostat, cultured at a temperature of 30-32 degrees Celsius for about 3-5 days, the strain can reproduce vigorously. After passing the inspection, pour out the water from the petri dish or flask and dry at a temperature of 35-40 degrees Celsius. After drying, store it in a cool and dry place and keep it ready.

Koji-making: koji, also known as koji, is an aspergillus strain used for koji-making. Koji seed production should be carried out in a special koji room. The day before inoculation, put the disc and tools indoors, seal, burn formaldehyde, carry out drug sterilization, and open the skylight about 1 day and night later to let the drug gas escape. The raw materials for koji seed production can be wheat bran, rice, millet and sorghum. The commonly used formula is: wheat bran 70% muri 80%, rice bran or rice husk 10%, fresh distiller's grains 20% 30% with about 60% water content. Mix the raw materials with water, add 75%-85% of the amount of water, place and moisturize for 1 hour, sift, and then cook in the pan for 45-50 minutes. After steaming, go out of the pot, cool to 370.38 degrees Celsius, insert the bacteria cultured in petri dishes according to 0.1% UV 0.2% inoculum, and shovel them evenly, accumulate at 32-35 degrees Celsius for 4 hours and mix once in the middle. Then pack the material in the crankplate, which is about 1 cm thick, and then store the crankplate at a temperature of about 30 degrees Celsius. The temperature of the material at this time is 2830 degrees Celsius. After 5-7 hours, the temperature of the material gradually rises to 32-34 degrees Celsius, and the stacking form of the disc should be reversed. After that, mash the koji three times every 3-4 hours and keep the temperature no more than 35-36 degrees Celsius. From inoculation, after 48-50 hours, the spores have grown, and the temperature of the material begins to drop or no longer rise, then the room temperature can be increased, the skylight of the curved room can be opened and dried at 35-40 degrees Celsius for 5-6 hours. After drying, store the koji seeds in a cool and dry place and keep them in reserve.

Koji making: qu is a saccharifying agent that can be directly put into production. Music-making should be carried out in a special music room. Koji-making materials are generally mixed with 5%-10% grain bran or bran, or 20%-30% fresh distiller's grains. When making, mix the raw materials with water, and the amount of water added should be determined by the water content of wheat bran and distiller's grains, which can be calculated by the following formula.

Water weight = raw material weight * (required water content% ~ raw material water content%) / (1 ~ required water content%)

The required water content is generally 45% to 50%. Sift the material mixed with water for 1 hour, soak the raw material with water, boil it in the pan for 45 minutes, remove it, spread and cool to 37 degrees Celsius, enter the koji seed according to 0.3% 0.5% inoculation, mix well. The koji material after inoculation is sent to the koji room. Accumulate at 28 degrees 30 degrees Celsius for 4 hours and stir once. Stack for another 1 / 2 hours, mix well, and load into a crankplate with a thickness of 2 / 2. 5 cm. Then stack each plate into a square column, after loading for 4 hours, the material temperature can rise to 36-37 degrees Celsius, and pull the plate at this time. The so-called pull plate is to pull the curved plate stacked into a square column at a certain distance and show a zigzag shape in order to facilitate air circulation and discharge carbon dioxide produced by Aspergillus. After pulling the plate for 5 hours, the material temperature rises rapidly, reaching 41-42 degrees Celsius, and the plate is buckled at this time. The so-called buckle plate is to buckle the empty koji plate upside down on the qu plate, and then flip each other, so that the koji material falls into the empty plate from the original plate, so that the koji material originally pressed below grows Aspergillus. After buckling the plate, the crankplate is still stacked with finished glyph, and the position of the crankplate is adjusted timely according to the change of material temperature, so as to keep the material temperature in each plate basically the same. In the process of making qu, the temperature of the music room should be kept at 2833 degrees Celsius. Generally starts from the inoculation, after 40-45 hours, can produce qu. Bran koji that has been made should be put into production immediately and should not be stored for a long time.

② wine mother: the expanded culture of yeast is generally divided into test tube culture, flask culture, Castell pot culture and wine mother stage.

Test tube culture: first soak the barley in cold water for 24 hours, change the water three times in the middle, then spread it on the bamboo curtain or bamboo screen, and allow it to germinate at room temperature. When the length of the leaf bud is equal to that of the barley grain, crush it, add 1.5 ~ 2 times water, saccharify at 60 degrees Celsius for 1 to 3 hours, and then filter with a cloth bag. Adjust the sugar content to 12-13 degrees, add sulfuric acid to adjust the pH to 0.2-0.4, put the sugar solution into the test tube, about 5 milliliters per tube, cook and sterilize for about 1 hour, once a day and night, for three times. The last sterilization, placed overnight, while aseptic access to a small number of test tubes cultured yeast, at a temperature of 25-26 degrees Celsius, 22-24 hours. After passing the inspection, it can be used for expanded culture.

Triangular flask culture: can be carried out in triangular flasks and flasks. The culture medium and culture method used were the same as those of test tube culture, but the culture multiple was expanded to 8: 10.

Castell pot culture: first stir the sweet potato powder and its 2 times the water into the slurry, and then put 3 times the weight of the sweet potato powder into the pot to boil, then pour in the sweet potato powder slurry, stir and cook for 40 minutes. After discharging, the gelatinized mash can be obtained by filtering with coarse cloth. Put the gelatinized mash into a sterilized Karl jar, add 8% to 10% koji, and saccharify for 1 to 3 hours at a temperature of 60 degrees Celsius. The sugar content was adjusted to 12-19 degrees and pH was 0.3-0.35. Then sterilize in steam or boiling water for 1 hour. After cooling, insert the yeast cultured in the flask according to the inoculation amount of 7% to 10%. Culture at 27: 28 degrees Celsius for 20: 22 hours, stirring once every 4: 5 hours, waiting for vigorous reproduction and qualified inspection, it can be used as a wine mother.

Wine mother: mix sweet potato powder, fresh distiller's grains, rice bran and water in the proportion of 100, 20, 5, 50, sift out the coarse grains, moisturize for 3 to 4 hours, and cook in the pot for 40 minutes. Then put the material in the sterilized yeast culture tank, add water, and add acid to adjust pH to about 4.3, then add 8% to 10% seed koji, mix well. When the feed temperature is 25-27 degrees Celsius, enter the yeast mash cultured in the Castell pot according to 5%-7% of the inoculation amount, and culture at 25-26 degrees Celsius for 8-10 hours. After maturing, the yeast can be used as a yeast for production.

③ cooking gelatinization: dried sweet potatoes are crushed, sifted and watered into 13%-15% slurry, then boiled in a pot. Cooking time is related to firepower, often judged by experience, generally about 40 minutes can be steamed through, you can get gelatinized mash.

④ saccharification fermentation: bran koji and wine mother can be added to the gelatinization mash at the same time. When the gelatinized mash is cooled to 20 degrees Celsius, add 8%-10% bran koji and 3%-5% mother wine to mix well, and add water according to the proportion of 60% water in the material. In the case of no more than 20 degrees Celsius, put the material into the ceramic tank fermentation tank or cellar, seal and carry out saccharification fermentation. In the process of fermentation, the temperature of the material rises gradually, generally 28 degrees Celsius, up to 40 degrees Celsius and 42 degrees Celsius, and the moisture is maintained at about 65%. The fermentation time is determined by many kinds of solid elements, such as temperature, air temperature, heat dissipation of materials, crushing degree of raw materials and starch concentration, etc. Generally, fermentation can be completed in about 3 days. After fermentation, the material can be sent to distillation.

⑤ distillation: the separation of refined ethanol from the crude product is carried out in an intermittent distillation column. The fermentation mash was put into a still and heated with indirect steam and direct steam. After boiling, the material liquid was kept boiling and the volatile components including ethanol were vaporized. The steam escapes from the top of the tower and condenses into the condenser to form a liquid. At the beginning of distillation, all the condensate flows back to the tower from the top of the tower (called stuffy tower in production). Its main purpose is to concentrate ethanol. The temperature of the reflux liquid from the condenser should not be lower than 50-56 degrees Celsius, so as not to destroy the operation of the distillation column. The condenser began to steam out ethanol after being stuffed in the tower for 1.5 hours. At the beginning, the first impurities are lower than the boiling point of ethanol, then the finished ethanol, and finally the tail impurities whose boiling point is higher than ethanol, which should be received in different containers. When the ethanol fraction is finished, the heating can be stopped. After the feed liquid is cooled, open the residual liquid discharge valve at the bottom of the kettle, release the residual liquid, clean the tower, kettle, condenser, cooler and other equipment with clean water, and then reload for the next step of distillation.