Deep-fried Crab Balls With Vinegar Dip

• 6 water chestnuts (peeled)
• 2 eggs
• 1 scallion
• 475 ml deep-frying oil
• 130 gr crab meat (fresh cooked)
• 32 gr pork fat from loin
• 30 ml black chinjiang vinegar
• 30 ml dry sherry
• 16 gr cornstarch
• 10 ml soy sauce (thin)