This section is from the book "A Handbook Of Invalid Cooking", by Mary A. Boland. Also available from Amazon: Handbook of Invalid Cooking.
From Strawberries. Remove the stems from one quart of strawberries, and pick them over carefully. Wash them under a stream of water in a colander, gently, so that they may not be crushed; then put them into a double boiler with half their bulk of sugar, and heat for an hour or more until the berries are soft. When this is accomplished, turn them into a jelly-bag and drain until the juice has completely oozed out, which will require two or more hours. Do not squeeze them. Then put the juice into a saucepan and, returning to the fire, heat it to a temperature of 200° Fahr., and keep it at that temperature for one hour. If a thermometer is not at hand, heat the juice until it steams a little, but do not let it boil, for the flavor is not nearly so delicate with the high temperature. Then it may be canned or bottled for future use. If the bottle be scalded and carefully sealed as in preserving fruits, the juice will keep indefinitely.
The length of time that it remains at 200° is important, as it is a process of sterilization which takes place, and the temperature must be maintained for a given time or the desired result will not be accomplished. The condition of the bottle also must be carefully considered, as the thorough cleaning and scalding is for the purpose of rendering it sterile. This is most easily and thoroughly done by filling the bottle with hot water and placing it in a kettle of boiling water for half an hour.
To Use. Dilute the juice with cool water (not iced water) or soda-water in the proportion of one half juice to one half water.
From Oranges. The oranges should be peeled and the seeds removed, and then treated in the same way as the strawberries in the preceding rule, except that to every quart of fruit the juice of two lemons should be added.
From Raspberries. Employ the same method as for strawberries.
From Currants. The same as for strawberries, except that three fourths of the bulk of the fruit of sugar should be used instead of one half.
With Other Fruits. Other fruits, such as apricots, peaches, cranberries, apples, etc., may be used for syrups, varying the water and sugar according to the kind of fruit used. Apples, apricots, and peaches will require half their bulk of water.
 
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