The Kam Man Food supermarket sells more than 20 varieties of rice, catering to subtle differences in palates among Chinese, Vietnamese, Korean, and other Asian cultures.

It is that kind of need-based variety that has helped Kam Man double in size in the 10 years since it opened in Quincy, to its current 80,000 square feet, as the city’s Asian population, already the most dense in the state, continues its steady expansion.