The most important thing about steaming crabs is to keep the fresh flavor of the crab, and to steam the crab without overdoing it. The most likely problem in the process of steaming crabs is that they are steamed for too long, resulting in meat that is not fresh and sweet, or they are steamed for too little time and have parasites. You can't generalize the steaming time for crabs because a whole crab takes a completely different amount of time than a cut-up crab. Whole live crabs need to be steamed by boiling water first, then steaming over high heat for about 5 minutes, then switching to low heat to continue. Crabs under 3 taels should continue to be steamed for about 10 minutes, those weighing 3 to 4 taels should continue to be steamed for about 12 minutes, and those weighing more than 4 taels should continue to be steamed for about 15 minutes. Usually, for every 1-two increase in weight, the steaming time will increase by about 2 minutes. In short, the exact time for steaming crabs needs to depend on the size of the crab.