한국콩연구회

finger press. The cooked soybean is poured in a sack and crushed by stepping on the sack or pounded in a mortar. The crushed soybean is molded into a brick, a cone or a ball shape. It is placed on the rice straw, dried in the sun and stacked under a cover during the night for a week. When the outside is dried, it is tided with rice straw and hung under the ceiling of warm living room. Normally Meju preparetion starts in October, the beginning of Korean autumn, and the slow drying process undergoes for 10 weeks in the room.

 During this periods, molds grow on the surface of Meju ball, and bacteria, especially Bacillus species, grow in the inside of the ball hung in the room is taken into a sack made by roce straw and kept in the storage room. It is periodically taken out in the sun for a half day drying.

 In the next spring, Meju ball are taken out from the straw sack and brushed out the surface mold and straw dirts, and put in a large earthen jar washed with boilling water and filled with brine. The mixing ratio of Meju, water and  salt is 2:4:1.2 in volume, which makes the salt concentration of the mash around 20%. Small amounts of charcoal, dried whole red-pepper and dried date are added to the jar, which is placed in the sunny place and covered with fine net in order to protect from flys. The ripening of soysauce mash in the brine is ended in 1-2 months.

 During this period, the amino acids and sugars formed by the enzymic hydrolysis of soybean proteins and carbohydrates exude out to the brine and they undergoes maillard reaction to produce dark brown color. The halophilic yeasts, mainly Saccharomyces rouxi, grow in the mash and produce alcohols and other organic compounds to add the flavor of the sauce. At the end of the ripening the mash is filtered and the liquid part is boiled and kept in the earthen jar for longer periods of storage.

 The precipitates remained after filtration is mixed with small amounts of Meju powder and rice porridge, packed in a small earthen jar with additional salt spread on the top, and kept in the sunny place for several weeks to make soybean paste.

On the other hand, the fermentation starter for Japanese style sousauce, Koji, is made by controlled fermentation of a inoculated mold, Aspergillus oryzae, on the mixture of roasted brocken wheat and cooked soybean or defatted soybean meal. Koji is mixed with brine to make soysauce mash for ripening. The mixing ratio of Koji, water and salt is 1:7:1.8, and the higher soybean content in the mash results in stronger meaty flavor but less sweet taste. The mash is stirred once in a day, and ripening continues normally for 1-2 months, but the longer period of ripening, for example 6 months or one year, produces better quality of soysauce. After ripening the mash is filtered to separate clear liquid and the residue which are discarded. The clear liquid is sterilized by boiling and then bottled for sale. Soybean paste is made separately in Japanese style soybean fermentation. Rice Koji is mixed with cooked soybean and salt, and ground to make paste. It is packed in a container and ripened for several weeks. The pure culture of mold excluding the growth of Bacillus and the use of cereals in the starter render the products milder aroma and sweeter taste.

 Korean soysauce making is a natural fermentation having various microflora incorporated sequentially in the processing steps. Although the amylolytic and proteolytic activities of the mold grown on the surface is high, much stronger enzyme activities are expested from the anaerobic bacteria grown inside the Meju. At the end of Meju fermentation, the inside of Meju ball is dark brown and has strong smell.

 During the ripening in the brine, this smell turns more acceptable and savory nature by complex chemical and biochemical reactions, and further chemical reactions including the esterification of organic compounds with alcohols take place during the long periods of storage after filtration and boiling. The biochemical reactions taking place during the fermentation and storage of Korean soysauce are very complex and not fully understood yet.

 Due to the action of Bacillus species and the raw material using soybean only, Korean soysauce has stronger meaty flavor, less sweet and sharper smell compared to Japanese style soysauce.

 Korean people prefer to use home-made soysauce as the condiments for soup and dipping sauce for various dishes, especially for boiled pork. The strong and sharp flavor of Korean soysauce became smoother and deeper during the long period of storage in the earthen jar, and the dishes made with 10-year old soysauce can produce extraordinary harmony of taste.   [k]