BRING THE WATER AND WINE to a boil over high heat. Wash all the fish trimmings. Add the fish trimmings, lemon juice, onion, celery, parsley, thyme and peppercorns to the pot. When the water returns to a boil, reduce the heat so that it is barely simmering, and simmer for 2 hours. Strain the stock, extracting as much liquid as possible from the solids. Discard the solids, and allow the stock to reach room temperature before refrigerating or freezing. Makes 3 litre s. The stock can be refrigerated up to four days, or frozen for up to six months.