TECHNOLOGY FOCUS - MECHANICAL ENGINEERING - Preferred Device: Bubble catcher is connected above the generator in sealing manner. It communicates with a gas-liquid separator by a carbon dioxide condensed exhaust pipe. The liquid output end of the gas-liquid separator communicates with the mash storing box. The gas output end of gas-liquid separator is connected with a carbon oxide purifier communicating with a pressure stabilizing gas storing chamber provided with a compressed gas input opening at the bottom of the generator by a gas compressor. The inner wall of the generator is cylindrical. The injection direction in which the mash delivery pipe enters into the generator is in parallel with the cross-sectional direction of the inner wall of the generator. The injection direction in which the compressed gas input opening of pressure stabilizing gas storing chamber enters into the generator is in parallel with the middle axis of the generator. The input opening of the air compressor is connected with an air input pipe provided with an air purifier. The bubble catcher, mash delivery pipe, and pressure stabilizing gas storing chamber are respectively provided with flow rate control valve, respectively, electrically connected with a temperature controller electrically connected with a temperature detecting unit capable of detecting the temperature of the mash solution in the generator. The temperature controller is further electrically connected to the control circuit of the gas compressor.    TECHNOLOGY FOCUS - ORGANIC CHEMISTRY - Preferred Method: Before the step of extracting juice, the method further comprises pretreatment step comprising firstly removing the branch, leaves, and sheath wrapped on the stalk; and washing. After the step of extracting juice, the method further comprises preparing juice by acidizing, diluting, and adding nutritive salt into the juice. Acidizing comprises directly adding diluted hydrochloric acid into the raw juice; and detecting the pH of the juice until 4-4.5. Diluting comprises adding water into 74-80% raw juice to dilute into 25%. Adding nutritive salt comprises adding nitrogen and magnesium salt into diluted juice; and uniformly stirring, where nitrogen accounts for 0.15-0.18% of the sugar content in the juice, magnesium salt accounts for 0.05-0.06% of sugar content in the juice, and the content of sugar is 25 mass% of the total mass of the juice.