Plums are rich in vitamins C and B3, potassium and antioxidants, and they strengthen blood vessels, support the heart and improve digestion. This guide sets out six plum jam recipes, from classic preparations to versions with citrus, chocolate and even cognac, along with advice on choosing the right pot, checking when the jam is done and storing it.
Choosing plums for jam
For jam made with whole slices, choose firm, ripe fruit with no rot, since these hold their shape during cooking. For a smoother jam, overripe, soft plums work better because they break down faster into a uniform mass.
The best variety for jam is the Hungarian plum, the same variety typically used to make prunes. It has firm flesh, a small pit that separates easily, and a rich sweet taste with a slight tartness. Plums with damage, cracks or signs of rot should be avoided, as they spoil the flavor of the finished product.
Preparing the plums
Before cooking, wash the fruit thoroughly under running water, remove the stems and leaves, and take out the pits, either by cutting the plum along its natural seam. The pit in Hungarian plums comes out easily. Cut the plums in half or into quarters so they absorb the sugar better and keep their shape.
Choosing a pot for plum jam
A stainless steel basin works best, since its wide base lets moisture evaporate quickly, so the jam thickens evenly without burning, and the acid in the plums does not react with the metal. A thick-bottomed stainless steel pot is an acceptable alternative, though its higher sides slow evaporation and require longer cooking. An enameled pot or basin also works, since the enamel does not react with the acid, but it must be free of chips or the jam will burn.
Aluminum and copper cookware should never be used for plum jam. Aluminum ruins the color of the jam and gives it a metallic taste, while copper destroys the vitamins in the fruit.
Classic plum jam with sugar
This recipe calls for 1 kilogram of plums and 1 kilogram of sugar. Place the prepared plums in a pot or wide basin and cover with sugar, mixing gently with a wooden or silicone spoon so the sugar spreads evenly without damaging the slices. Leave for two to three hours at room temperature, or overnight, so the plums release their juice and the sugar begins to dissolve.
Place the pot on the stove over the lowest heat and bring to a boil while stirring gently so the sugar does not burn on the bottom. Once it boils, turn off the heat and let it cool completely at room temperature, uncovered, so excess moisture can evaporate. This cooling takes about three to five hours, or overnight.
Bring the jam to a boil a second time over low heat, stirring occasionally, then turn off the heat and let it cool fully again. By this stage the plums will have absorbed the syrup and turned translucent. Bring it to a boil a third time and cook for about 35 to 40 minutes, stirring constantly and skimming off the foam regularly, until the syrup turns clear and amber.
Pour the finished jam immediately into hot sterilized jars, filling them to the top, and seal tightly with a canning key. Check the seal by turning the jars upside down to make sure nothing leaks. Once fully cooled, store the jars in a cool, dark place.
Spiced plum jam baked in the oven
This version uses 2 kilograms of plums, 1 kilogram of sugar, two cinnamon sticks, five star anise pods and one tablespoon of lemon juice. Remove the pits from the plums and place the fruit in a deep pot. Cover with sugar, add the cinnamon and star anise, and pour over the lemon juice. Let it stand for two hours or longer.
Heat the oven to between 150 and 160 degrees Celsius. Simmer the plums for two hours, stirring occasionally, until the syrup thickens. Transfer the finished jam into sterilized jars and seal.
Plum jam with orange and lemon
This bright, fragrant jam has a citrus tartness and pairs well with pancakes and fritters.
It calls for 1 kilogram of firm plums, one orange, half a lemon and 1 kilogram of sugar. Wash the plums, orange and lemon thoroughly. Remove the pits from the plums, and cut the orange and lemon into wedges, removing their seeds but leaving the peel on. Pass all the ingredients through a meat grinder.
Add sugar to the mixture, stir and let it sit for several hours at room temperature. Place the pot over medium heat, bring to a boil, then reduce the heat and cook for about 50 to 60 minutes until done. Pour the hot jam into sterilized jars, seal and leave to cool at room temperature. Store in a cold place.
Plum jam with chocolate and cognac
This recipe uses 1 kilogram of ripe plums, 1 kilogram of sugar, 10 grams of dark chocolate and 10 milliliters of cognac, or more to taste. Wash the plums and remove the pits, cover with sugar, then cover the pot and refrigerate for a couple of days until the sugar dissolves.
Place the pot over medium heat and skim off the foam once it boils. Cook in two stages: bring to a boil the first time, skim the foam and cool at room temperature, then bring to a boil a second time, cook for five to seven minutes, turn off the heat and stir in the chocolate. Let it cool for another 20 minutes, then stir in the cognac. There is no need to boil it again after that. Pour into sterilized jars and store in the refrigerator.
Plum jam (jam-style, smooth)
This thick, smooth jam becomes marmalade-like once cooled, making it ideal for pie fillings and toast.
It requires 2 kilograms of plums and 1 kilogram of sugar. Wash the plums and remove the pits, then place them over medium heat for 30 minutes until they release their juice and soften. Puree the mixture with a blender or pass it through a meat grinder.
Add the sugar, stir and place back on the stove. Cook down for about 30 minutes until thickened, keeping the consistency not too thick, since it will thicken further as it cools. Pour into clean jars and seal.
Plum jam with less sugar
This version suits those who prefer a less sweet jam.
It uses 1.5 kilograms of plums and 700 grams of sugar. Cover the prepared plums with sugar and leave overnight. Cook the first time for five minutes over high heat, stirring constantly. Five hours later, cook again for 15 minutes over low heat. If the jam is not yet ready, once it has cooled, cook a third time for 10 minutes over low heat. Pour the hot jam into sterilized jars and seal.
How to tell when plum jam is done
Several tests help check whether the jam is ready. Drop a spoonful of hot jam onto a cold saucer: if the drop holds its shape without spreading, it is done, and if it spreads out, it needs more time. Scoop up jam with a spoon and lift it above the pot: if the syrup flows in a thin, unbroken thread, the jam is ready, but if it drips in separate drops, it is not. A thermometer can also help, since finished jam reaches 104 to 105 degrees Celsius.
Doneness can also be judged by sight. The jam is ready when the syrup turns clear and amber, foam barely forms anymore, and the plum slices become translucent.
How and how long to store plum jam
The ideal storage spot is a pantry, basement or cellar with a temperature between 5 and 15 degrees Celsius. How long the jam keeps depends heavily on whether it was made with or without the pits.
Jam made without pits can keep for one to two years. In hermetically sealed, sterilized jars it can last a full two years, though the flavor is richest in the first year. Jam made with pits keeps for no more than six to eight months, since over time the pits release substances that can give the jam a slightly bitter taste and change its color. Once opened, jam should be kept in the refrigerator and used within one to three months.
