As a general rule, the more watery the fruit the more reduced the syrup of sugar must be. If it is not reduced enough, small pieces of ice, formed by the water of the fruit, will be found while eating it. The fruit must be ripe. It is done also with preserved fruit. It is impossible to tell exactly the degree or state of the fruit and syrup without a hydrometer.
The following preparation may be added to the fruit, or to punch, as soon as it begins to freeze; it is not indispensable, but gives it more body: Put one pound of loaf-sugar in a copper pan with two gills of cold water, set on the fire, stir now and then till it comes to a boil, then boil till it is at the fifth state or 43 deg., and take off. Beat four whites of eggs to a stiff froth, flavor with essence of vanilla, and turn the sugar into the eggs, little by little, but do not stop beating until the whole is in. Then move the mixture gently round with a spoon for about a minute, and it is ready for use.