Ripe cherries are washed and cleaned from the stems and pits, crushed and flooded with water. Boil 5 minutes. Juice strain, add sugar (to 1 liter juice - 800 g of sugar) and boil for 5-10 minutes. Dissolved pectin is added in a thin stream. Mix and boil to give the required density. 2-3 minutes before removing from heat and add the tartaric acid.