Stuart Morrow’s recipe, for 750 ml: add 2.5 g of citric acid, 2.5 g of ascorbic acid, and 2.5 g of malic acid to 250 ml of Lillet Blanc. Add 2 pcs of ground lime zest and 50 g of cut ginger. Pour in 250 ml of Riesling and 250 g of passionfruit pulp. Place the resulting mixture in a bag, squeeze the air out with a vacuum, and boil for an hour at 60 ºC. Then place the bag in an ice bath, chill, and let steep for 24 hours. Filter the liquid into a separate bottle and store in the refrigerator.