Gansu jiangshui noodles

Step 1: Whisk 2 tbsp plain flour into 6 ¼ cups water and boil for 2 minutes, until it turns slightly cloudy. Leave to cool completely.

Step 2: Blanch 10 ½ oz celery or Chinese cabbage in boiling water for 30 seconds and drain. Pack it into a clean 2-litre jar, pour in the cooled flour water and 2 tbsp sauerkraut brine (unpasteurised), and cover loosely with a lid or cloth.

Step 3: Leave in a warm place (about 77°F) for 3–4 days, until the liquid smells pleasantly sour and slightly fizzy and the vegetables look olive-coloured. Common mistake: sealing the jar tight or leaving it in a cold room; it needs warmth and air. Throw it away if it turns pink, slimy or mouldy.

Step 4: Heat 2 tbsp vegetable oil in a pan over a medium heat. Fry 4 dried red chillies, ½ tsp Sichuan peppercorns and 3 cloves garlic for 30 seconds until the chillies darken and the oil smells spicy. Add 3 ½ oz garlic chives (jiu cai) and stir for 20 seconds until wilted.

Step 5: Pour in 1 litre of the jiangshui liquid with a few spoonfuls of the pickled vegetables. It will hiss loudly. Bring to the boil, season with 1 tsp salt and taste: it should be sour, salty and lightly spiced.

Step 6: Cook 14 oz fresh wide wheat noodles in plenty of boiling water for 3–5 minutes until just tender, then lift into bowls.

Step 7: Ladle the hot broth and vegetables over the noodles and add 2 tbsp chilli oil to taste. Top up the jar with more cooled flour water to keep the ferment going.