First and foremost, you will need ripe plums. Look for plums that are slightly soft to the touch and have vibrant colors. The best time to make plum jam is when plums are in season, typically around late summer or early fall. Choose plums that are sweet and flavorful to ensure the best taste in your jam.
Once you have your plums, wash them thoroughly and remove any stems or blemished areas. If you prefer a smoother consistency, you can also peel the plums, although this step is optional. Cut the plums in half, remove the pits, and chop them into small pieces. It’s up to you how chunky or smooth you want your jam to be.
Next, prepare your canning jars and lids. Proper sterilization is essential to prevent any bacterial growth or spoilage. Thoroughly wash the jars and lids in hot, soapy water, or run them through a dishwasher cycle. Once the jars are clean, place them in a large pot of boiling water for about 10 minutes to sterilize them. Remove the jars from the boiling water and let them air dry.
Now, it’s time to start cooking your plum jam. In a large, non-reactive pot, combine the chopped plums with sugar and lemon juice. The amount of sugar will depend on the sweetness of the plums and your personal taste. As a general rule, for every pound of plums, you will need about ¾ to 1 cup of sugar. The lemon juice adds a touch of acidity that helps preserve the jam.
Place the pot over medium heat and bring the mixture to a boil, stirring occasionally. As it boils, the plums will release their juices, and the sugar will dissolve, giving the jam a thicker consistency. At this point, you can also add any additional flavorings or spices you desire, such as vanilla extract or cinnamon, to enhance the taste.
Once the jam reaches a rolling boil, reduce the heat to low and let it simmer. Stir occasionally to prevent the bottom from sticking or burning. As the jam cooks, it will gradually thicken and darken in color. Simmer the jam for about 30-40 minutes, or until it reaches the desired consistency. You can test the jam’s readiness by placing a small spoonful on a chilled plate and tilting it. If the jam holds its shape and doesn’t run, it’s done.
Once the jam is ready, carefully ladle it into the sterilized jars, leaving about ¼ inch of headspace. Wipe off any spills or drips from the jar rims using a clean, damp cloth. Place the lids on the jars and tighten until just snug. To seal the jars properly, you can either process them in a water bath canner for about 10 minutes or follow the manufacturer’s instructions for your specific canning lids.
After processing or sealing the jars, let them cool undisturbed for several hours or overnight. During this time, the jam will continue to thicken and set. Once the jars are completely cooled, check the seals by pressing down on the center of each lid. The lids should feel firm and not move or make any popping sounds. Store the sealed jars in a cool, dark place for up to one year.
Making your own plum jam at home is a rewarding and delicious endeavor. Not only will you be able to enjoy the sweet and tart flavors of fresh plums all year round, but you can also gift your homemade plum jam to friends and family. So, don your apron, gather your plums, and get ready to embark on a delicious jam-making adventure!