Pick over 1 cup of raspberries and wash them in cold water. In a pot add 1 1/2 cups of water to 3/4 cups sugar, mix and bring to boil. Add cleaned raspberries to the hot syrup, bring to boil, turn off the heat, cover the pot and leave to infuse 15-20 minutes. Strain the raspberry infusion, add lemon acid to taste, slightly cool, pour into molds and let it set. If desired — decorate jello with whole berries.