Wash and pack closely in jar. Cover with medium syrup, put on rubber and top and adjust top bail or screw on top with thumb and little finger. Sterilize 16 minutes in hot-water bath. Remove, complete seal and cool.
PRINCIPLES OF JELLY MAKING
To be satisfactory, jelly must be made from fruit juice containing pectin and acid. Pectin is a substance in the fruit which is soluble in hot water and which, when cooked with sugar and acid, gives, after cooling, the right consistency to jelly.
Fruits to be used should be sound, just ripe or slightly under-ripe, and gathered but a short time. Wash them, remove stems and cut large fruits into pieces. With juicy fruits add just enough water to prevent burning while cooking. In using fruits which are not juicy cover them with water. Cook slowly until the fruits are soft. Strain through a bag made of flannel or two thicknesses of cheesecloth or similar material.
Test for Pectin
To determine if the juice contains pectin, boil 1 tablespoonful and cool. To this add 1 tablespoonful of grain alcohol and mix, gently rotating the glass. Allow the mixture to cool. If a solid mass—which is pectin—collects, this indicates that in making jelly one part of sugar should be used to one part of juice. If the pectin collects in two or three masses, use 2/3 to ¾ as much sugar as juice. If it collects in several small particles use ½ as much sugar as juice. If the presence of pectin is not shown as described it should be supplied by the addition of the juice of slightly under-ripe fruits, such as apples, currants, crab-apples, green grapes, green gooseberries or wild cherries.
Measure the juice and sugar. The sugar may be spread on a platter and heated. Do not let it scorch. When the juice begins to boil add the sugar. Boil rapidly. The jelly point is reached when the juice drops as one mass from the side of a spoon or when two drops run together and fall as one from the side of the spoon. Skim the juice, pour into sterilized glasses and cool as quickly as possible. Currant and green grape require 8 to 10 minutes' boiling to reach the jelly point while all other juices require from 20 to 30 minutes.
When the jelly is cold pour over the surface a layer of hot paraffin. A toothpick run around the edge while the paraffin is still hot will give a better seal. Protect the paraffin with a cover of metal or paper.
Three or more extractions of juice may be made from fruit. When the first extraction is well drained cover the pulp with water and let it simmer 30 minutes. Drain, and test juice for pectin. For the third extraction proceed in the same manner. The juice resulting from the second and third extractions may be combined. If the third extraction shows much pectin a fourth extraction may be made. The first pectin test should be saved for comparison with the others.