136 CHEMICAL INDUSTRY IN KWANGTUNG PROVINCE 



which is caused by a group of bacteria. These micro- 

 organisms cause the oxidation of the alcohol into acetic acid. 

 The wines to be used must not be too strong. 



Three kinds of vinegar are made in Kwangtung : — the 

 white, black, red. 



White vinegar is made by using the by-product of wine 

 distillation, that is 12 catties of this by-product are added to 

 440 catties of water and the mixture is boiled to 80 deg. C, 

 and is placed in large containers, then 65 catties of rice wine 

 are added and the whole mixture is allowed to stand for 

 30 days during which time the bacteria change the wine into 

 vinegar. 



Black vinegar is made from the white vinegar by adding 

 to the latter roasted red rice. 



Red vinegar is made by using a special kind of rice the 

 fermentation of which gives (1) alcohol and (2) vinegar. 



Peanut Oil. — Peanut oil is used for food by nearly all the 

 people in South China. In the North, bean oil is used. As 

 peanut oil is cheaper than lard, it is used in place of it. 



Peanut oil is a light greenish yellow oil when it is pure. 

 It has a peculiar odor and taste, but when refined, the best 

 quality of oil is colorless and has a very faint nutty taste. 

 Its specific gravity is .916 to .922. 



Peanut oil is made in Canton, but the largest peanut oil 

 factory is in Sin Toen fill 14 . Here the peanuts are first 

 crushed by a machine which crushes 10,000 catties of peanut 

 a day. After the peanuts are crushed, they are steamed for 

 about 20 minutes, and then placed in rings and packed in the 

 form of round cakes. These rings are then placed in a press, 

 made of hard wood, the shape of which is like a Chinese 

 coffin. They are hammered with mallets weighing 25-50 

 catties until no oil runs out. 



As pressure is applied, the oil runs out into a vessel. 

 Then the peanuts which have been crushed and pressed are 

 taken out from the rings, are powdered and steamed again, 

 and then replaced in the presses to be hammered again, until 

 practically all the oil runs out. The residue which contains 

 no oil is dried and sold as fertilizer. This is a tedious and 

 slow process, for the crushed peanuts have to be hammered 

 for a long time before the oil begins to run out. 



The yield is 33%, that is out of 120 catties of peanuts 

 hammered in the presses, 40 catties of oil are obtained, and 

 as there are 24 presses, they can make 960 catties of oil per 

 day. About 30 men are employed so that each makes 30 

 catties of oil on the average a day. 



There are two kinds of peanut oil. The better kind is 

 light greenish yellow and is sold for 24 cents per catty. The 



