Rule 1.—Use only fresh fruit which has been gathered in dry weather.
2. Allow three-quarters of a pound of sugar to one pound of all fruit, except stone fruit. Stone fruit requires an extra quarter of a pound of sugar. Break the sugar small, but do not pound it; if the sugar is pounded the syrup will not be clear. Use the best sugar, as the inferior kinds produce much more scum.
3. Never set the preserving-pan flat on the fire. If you do, the fruit will stick to it, and burn. Raise the pan on a trivet a little above the fire, and not exactly over the hottest part. Stir the jam with a wooden spoon all the time that the sugar and fruit are boiling together. An iron spoon ruins both the flavour and the colour of jam. Stir gently at first, more quickly as the boiling of the jam proceeds. Skim off all scum as it rises.
4. Put the fruit into the preserving-pan, sprinkle in some of the sugar, and as the fruit juices, add the rest of the sugar by degrees. When the sugar is all dissolved bring the jam to the boil.
5. Never boil jam longer than twenty minutes. If it is boiled too long the jam will be sticky, but if not boiled enough it will not keep. When the scum ceases to rise, put a few drops of the jam on a cold plate, watch it for a minute, and if it sets, and does not flow freely, the jam is done.
6. Warm the jam-pots before you pour the hot jam into them; if you do not they may crack. Fill the pots to within half an inch of the top, and wipe off any drops spilt with a cloth wrung out in hot water. If this is not attended to, there will be great difficulty in scraping off the drops when the jam has cooled.
7. The day after the jam is made, and when it has become quite cold, lay a round of thin paper on the top of each pot. Then take a sufficient number of the vegetable parchment covers which are sold for tying over jam-pots, soak them for a minute or two in cold water, wipe them dry, stretch one over each pot, and tie it round with string. The parchment tightens as it dries, and excludes the air from the jam. When the covers are dry, write in ink on each the name of the jam and the date.
8. Always keep jam in a cool, dry place. Damp makes it mouldy, heat makes it ferment.
9. Never put one pot of jam exactly on the top of another, but set one row of pots on the edges of the row beneath, leaving a clear space in the centre of each pot.
Different fruits require different treatment when made into jam. Thus, strawberries must be carefully stirred, raspberries must be mashed with a wooden spoon; and both these fruits, being soft and juicy, require less boiling than the drier kinds. Dry fruits, such as apples, should always be put first into a covered jar set in a pan of boiling water, and kept there until they are thoroughly softened. Fruit, with the exception of the very juicy kinds, takes longer to boil than sugar, so that it is well to cook the fruit partially before adding the sugar. Over-boiled sugar spoils the texture of jam.