Gul (oyster), or guljogae, is written as moryeo (牡蠣) or seokhwa (石花) in Chinese characters. The oyster is a bivalve mollusk (family Ostreidae), of which there are 22 types that are all edible. The fact that oysters have long been consumed by Koreans is known from the discovery of oyster-shell mounds, throughout the Korean Peninsula, which date back to prehistoric times. There are also numerous references to oysters in ancient books, such as Sinjeung dongguk yeoji seungnam (新增東國輿地勝覽, Revised and Augmented Survey of the Geography of Korea), which states that oysters were a local product of all seven provinces, with the exception of Gangwon-do. As such, Koreans have long been familiar with the preparation and consumption of oysters.

Nutrient-rich
Referred to as the “milk of the sea,” oysters are very rich in nutrients. Oyster’s high iron content makes it a good food for people who suffer from anemia, and it is also known to help strengthen liver function. The oyster contains a high level of taurine, which helps to moderate blood pressure in the case of excessive salt intake, along with lowering cholesterol in blood plasma. Oysters are also a source of vitamins (A, D, E, B1, B2, C), niacin, potassium, calcium, and phosphorous, while its calcium is readily absorbed by the human body. In addition, the oyster is said to minimize stress-related ailments, quench your thirst, and promote a healthy complexion. Oysters also contain proteins, such as histidine and lidine. With a soft texture and being easy to digest, oysters can be served to all ages, from young children to the elderly, as well as people recovering from illness.
In the waters of Korea, oysters reach a peak, in terms of taste and nutrition, in autumn and winter, when they are most flavorful. During this period, the oyster also contains a high level of glycogen, an essential nutrient that serves to boost the body’s energy and metabolism. When oysters spawn in spring and late summer, they tend to be less tasty, due to an increase of calcareous content, along with being more perishable than in other times of the year. Raw oysters should be avoided during the hot summer months because of their elevated levels of toxins, as a result of the maturity of their reproductive organs. Moreover, the oyster is less flavorful at this time as well.

Practice Prudence
Because of the oyster’s unique flavor and soft texture, it is best eaten raw. However, the selection and handling of this shellfish must be undertaken with considerable care. When buying oysters, live oysters should be selected, to the extent possible. A fresh oyster has a clear milky-white color and lustrous surface. In addition, if you poke the flesh with your finger, it should be resilient to the touch. Of particular note, look for an oyster with clear lines on its flesh and resilient firmness.
Oysters should be eaten soon after they are purchased. An unshucked oyster, if refrigerated at a temperature of 10° C, can be kept for about a week, from the time of its harvest. Shucked oysters should be placed in sea water and refrigerated; however, their freshness will be lost after a few days.
As for natural versus cultivated oysters, it is difficult to distinguish between the two, based on appearance or taste. Nevertheless, cultivated oysters tend to be more uniform in size and are oftentimes somewhat larger than naturally grown oysters. In addition, there are annual regional variations between natural and cultivated oysters, while the taste and freshness can be affected by the preservation measures that are taken during the distribution process. Therefore, caution should be exercised when purchasing fresh oysters.

Preparation
A basic principle of handling fresh oysters, whether they are served raw or prepared for cooking, is to avoid contact with fresh water. To maintain the flavor and freshness of oysters, use salt water to rinse them off or if they need to be stored. Gulbap boasts a delightful flavor, fresh taste, and high level of nutrients. Although gulbap can be enjoyed year-round in Korea, it is most flavorful when prepared with newly harvested rice.
The following recipe is for a gulbap version that includes various seafood items and vegetables, together with jujubes and an assortment of nuts (walnuts, pine nuts, and ginkgo nuts). This combination of ingredients adds to and complements the oyster’s tastiness. For many people, a serving of gulbap is perfect when topped with soy sauce and mustard.

Gulbap (Oyster Rice)
Ingredients
3 cups rice, 20 grams kelp, 400 grams oysters, 100 grams small-size shrimp, 1 abalone, 50 grams radish, 30 grams pine mushroom, 3 chestnuts, 2 tablespoons ginkgo nuts, 4 jujubes, 1 tablespoon walnuts, sesame oil, flavored juice, seafood flavored soy sauce, oil, salt

Seasoning sauce:
2 tablespoons soy sauce, 2 tablespoons kelp water, 1 tablespoon chopped shallots, 1 tablespoon mustard sauce, 1/3 tablespoon maple syrup, 1 teaspoon citron syrup, dash of pepper

Preparation
1. Wash the rice and mix in sesame oil.
2. Add 20 grams of kelp, 1 tablespoon of flavored juice, 2 tablespoons of seafood-flavored soy sauce, and salt, to 2 cups of water, and bring to a boil. The flavored juice, which is optional, should be made from the juice of onion, garlic, ginger, and pear. Seafood-flavored soy sauce is made by boiling soy sauce with anchovy, kelp, skipjack tuna, squid, and onion. For this, diluted soy sauce can be substituted.
3. Rinse the oysters in salt water, and then parboil. Slice the shrimp and abalone into strips, and braise, along with the pine mushroom. Peel the chestnuts, and remove seeds from the jujube, then cut into quarters. Slice and parboil the radish.
4. Place the rice mixture from Step 1 in the boiled water prepared in Step 2. Cook the rice.
5. When the rice is thoroughly steamed, add the ingredients prepared in Step 3, as well as the various nuts. Mix together well. Allow the rice and ingredients to steep.
6. Combine the ingredients for the seasoning sauce. Add the seasoning sauce to the gulbap (oyster rice) and serve, while still warm.