Vietnamese-Style Crab Stock

In Vietnam, rice paddy or rice-field crabs, known as "cua đồng" in Vietnamese exist in the rice paddies or rice fields. They are similar in size as the green crabs found here in the Northeast United States. My parents tell me they cause havoc by eating young rice shoots. I have not found any research that confirms that they actually ingest or simply just cut the young shoots while foraging. People have found a way to catch and eat them to near extinction just like most wildlife in Vietnam, according to my father. My cousins in Vietnam tell me that in recent years there are fewer of these once abundant crabs due to excessive use of pesticide. Although many people including my cousins in Vietnam buy these tiny crabs so they can make the classic Vietnamese crab noodle soup known as bún riêu, but are afraid to eat these freshwater crabs because of the potentially harmful chemicals used. Cousin Khiêm, an inspector for seafood in Vietnam, tells me that due to a demand for these crabs in central and northern parts of Vietnam, people have started to farm them in these regions. He has not seen or heard of anyone farming for them in the southern part of Vietnam. One of my aunts who resides in Los Angeles, California recently sent me a photo of imported frozen rice paddy crabs from Vietnam labeled as"cua đồng" sold in plastic bags in her local Asian markets.

rice paddy in Vietnam

The stock or broth (riêu) is made using a traditional Vietnamese method by hand crushing the crabs to a pulp. Nowadays many people (in Vietnam) purchase the prepared crabs all ground up for convenience. You can use a blender to puree the crab bodies or you can hand pound the crab bodies, legs and claws. If you choose to use a blender you may want to avoid adding the legs and claws since these are tough and may damage your equipment. 

crush the prepared crabs with a heavy object on a stone

add a little water and stir well to help remove any crab bits

strain the liquid

repeat the process 2 more times or until the liquid is more clear

boil the broth until the fine crab meat floats to the surface in pieces

gently scoop and discard the white foam that floats to the surface

Vietnamese-Style Crab Stock

Ingredients:

Green crabs (see How to Prepare Hard-Shell Green Crab link)
Water

Method:

Prepare the crabs by removing and discarding the carapace, gills, and apron. Save the roe and/or crab mustard in a separate bowl to be used later. Discard the legs and claws if you prefer using only the bodies. Wash the prepared crabs with about 1 tablespoon of table salt. Rinse with cold fresh water 2-3 times to remove all the salt and drain off the water. Place the crabs in 1-2 freezer or heavy duty plastic bags and crush everything using either a hammer, stone or a heavy object against something hard such as a stone or brick. For best results add a handful of crabs at a time. Pour the crushed crabs in a pot or container. Repeat the process until all the crabs are crushed. Add a little water (about 1/3 of the total water you are using) to the crushed crabs and stir well to help remove the fine meat bits. Using a fine strainer, strain and filter out the crab meat and liquid. Add a little more water (about 1/2 of the remaining water you are using) to the crushed crabs and repeat the process until all the water is used up. By the 3rd and last time the water will become more clear with less crab bits. Save the strained fine crab bits and crab liquid for cooking. Discard the rest.

In a large pot add the crab bits and crab liquid, turn the heat to medium-high to high. Do not stir and let the broth comes to a gentle boil. Once it boils the fine crab meat will float to the surface in large pieces. Turn the heat down slightly if needed so the liquid does not boil over the pot. After about 4-5 minutes stir once and gently scoop out and discard the white foam (impurities) if interested. Avoid discarding the crab meat. Save the broth and crab pieces for making soups or stews.

Helpful Hints:

*1 pound of prepared green crabs can yield about 6-8 cups of broth. The less water you use will make your broth more concentrated and the more water will dilute your broth.
*The unused crab parts make great fertilizer for your garden. 
*My mother prefers to use only the green crab bodies when she makes this special stock. I use the bodies, legs and claws.