This is Mrs Beeton’s damson jam recipe, published in her Book of Household Management in 1907.
Note: this recipe is provided for information only, I have not tested it yet. Once I do I will add a recipe card.
The Original Recipe
Ingredients.—Damsons; to every lb. of fruit allow ¾ lb. of loaf sugar.
Mode.—Have the fruit gathered in dry weather, pick it over, and reject any that is at all blemished. Stone the damsons, weigh them, and to every lb. allow ¾ lb. of loaf sugar. Put the fruit and sugar into a preserving-pan; keep stirring them gently until the sugar is dissolved, and carefully remove the scum as it rises. Boil the jam for about an hour, reckoning from the time it commences to simmer all over alike: it must be well stirred all the time, or it will be liable to burn and stick to the pan, which will cause the jam to have a very disagreeable flavour. When the jam looks firm, and the juice appears to set, it is done; then take it off the fire, put it into pots, cover it down, when quite cold, with oiled and egged papers, and store it away in a dry place.
Time.—1 hour after the jam simmers all over.
Average cost, from 6d. to 8d. per lb. pot.
Sufficient.—1½ pint of damsons for a lb. pot.
Seasonable.—Make this in September or October.