Lu shui (鹵水, Cantonese: lo shui) is the Cantonese master braising liquid — a complex, aromatic soy-based broth used repeatedly over years to braise chicken feet, duck, offal, tofu, and eggs. Each item braised in the lo shui adds its own proteins, fats, and flavours, building a continuously deepening and evolving liquid. In Cantonese culture, a restaurant's lo shui, maintained over decades, is a jealously guarded asset — some Cantonese families have maintained the same lo shui for generations.
The lo shui base: 1L water, 500ml light soy sauce, 250ml dark soy sauce, 100ml Shaoxing wine, 100g rock sugar. Spice sachet: star anise (4 pieces), cinnamon (2 sticks), bay leaves (4), dried mandarin peel (2 pieces), Sichuan peppercorn (1 tbsp), fennel seeds (1 tsp), liquorice root (2 slices), sand ginger (sha jiang, 3 slices). Tie the spices in cheesecloth. Combine all in a pot. Bring to a boil. Simmer 30 minutes before the first use. Strain out the spice sachet. Maintaining the lo shui: After each braising session, bring the lo shui to a full boil (to kill bacteria), skim the surface, strain, cool, and refrigerate. Replenish soy sauce, water, and rock sugar after every 3-4 uses. Replace the spice sachet every 2-3 weeks. Braising times: Chicken feet: 45-60 minutes. Duck (whole): 45-60 minutes. Tofu: 30 minutes. Eggs: 30-45 minutes.
Eileen Yin-Fei Lo, Mastering the Art of Chinese Cooking (2009); Fuchsia Dunlop, Land of Fish and Rice (2016)