Shrimp pastes may vary in appearance from pale liquid sauces to solid chocolate-colored blocks. Shrimp paste produced in Hong Kong and Vietnam is typically a light pinkish gray while the type used for Burmese, Lao, Cambodian, Thai and Indonesian cooking is darker brown. While all shrimp paste has a pungent aroma, that of higher grades is generally milder. Markets near villages producing shrimp paste are the best places to obtain the highest quality product. Shrimp paste varies between different Asian cultures and can vary in smell, texture and saltiness.
Belacan, a Malay variety of shrimp paste, is prepared from krill, also known as geragau in Kristang or rebon in Sundanese and Javanese. In Malaysia, normally the krill are steamed first and after that are mashed into a paste and stored for several months. The fermented shrimp are then prepared, fried and hard-pressed into cakes. William Marsden, an English writer, included the word in his "A Dictionary of the Malayan Language" published in 1812.
Belacan is used as an ingredient in many dishes. A common preparation is sambal belacan, made by mixing toasted belacan with chilli peppers, minced garlic, shallot paste and sugar and then fried. Sometimes it is toasted to bring out the flavour, but this process creates a strong odor.
Recipe using Belacan paste see Here