If you’ve got some ripe plums on hand, making jam is a simple way to put them to good use.
This recipe keeps things straightforward – no peeling, not too much sugar, and it turns out with a fresh plum flavor that actually tastes like the fruit.
You can make it smooth or leave some chunks in, depending on what you like.
It works for fridge storage or canning, so you’ve got options either way.
Choosing the Right Plums
When it comes to making jam, not all plums are equal.
Best Varieties for Jam
For this recipe, black plums and elephant heart plums work really well. They have good flavor, deep color, and the right kind of flesh that cooks down nicely.
One thing to pay attention to is whether the plums are clingstone or loose-stone.
Loose-stone types are easier to deal with – the pit comes out without much trouble.
Clingstone plums, like elephant hearts, take a bit more work since the pit sticks to the flesh. But either type will make good jam, so it just depends on what you’ve got.
Ripeness Matters
This is one of the few times in the kitchen where overripe fruit is actually better. The softer and more ripe the plums are, the more flavor they bring to the jam.
Even fruit that’s starting to get a little wrinkly or bruised is just fine, as long as it’s not moldy.
If you have a tree, the best plums are the ones that fall off on their own or come off easily with a gentle tug.
Farmers' markets are also a good place to find ripe or even slightly overripe plums – sometimes they’ll have a discount bin just for that.
Ingredients
- Plums: Use about 5 pounds of whole plums. After pitting, you’ll end up with around 4 pounds of fruit. No need to peel them – the skins add flavor.
- Sugar: Use 1½ pounds. It’s enough to sweeten the jam without covering up the plum flavor. Add a bit more if your plums are sour.
- Pomona’s Universal Pectin (optional): Helps the jam set without needing a lot of sugar. You’ll need calcium water with it, which comes in the box.
- Lemon Juice: Needed only if you’re canning. It helps make the jam shelf-stable and brightens the flavor. Leave it out if you’re storing in the fridge.
- Unsalted Butter (optional): A teaspoon helps cut down foam while cooking.
Tools You’ll Need
- Wide Pot or Dutch Oven: A wide pan helps the jam cook down faster, which keeps more of that fresh plum flavor.
- Food Mill (Optional): If you like smooth jam, a food mill comes in handy. If you prefer it chunky or don’t mind the texture, you can skip it.
- Freezer-Safe Metal Spoons: These are used to test if the jam is done. Just stick a couple in the freezer before you start cooking.
- Jars with Lids: Whether you’re refrigerating or canning, you’ll need some clean jars. Pint-size jars work well for this recipe.
- Canning Funnel and Jar Lifter: These make it easier to fill the jars without making a mess, especially if you’re doing shelf-stable canning.
- Deep Stockpot and Rack (for Canning): If you're planning to can your jam, you’ll need a deep pot and a rack to process the jars in a boiling water bath.
How to Make Plum Jam
Whether you’re planning to keep it in the fridge or store it on the shelf, the process is straightforward.
Here’s how to do it from start to finish.
Step 1: Pit and Cut the Plums
Rinse the plums well. If you’re using loose-stone plums, just slice around the middle, twist the halves apart, and remove the pit.
For clingstone plums, it takes a bit more effort – slice along one side of the pit and trim the rest away with your knife. Keep the skins on; they give the jam its deep flavor and color.
Aim for about 4 pounds of plum flesh.
Step 2: Macerate the Plums
Put the cut plums into a large bowl. Add the sugar (and pectin, if using). Stir to coat the fruit evenly, then cover the bowl and refrigerate it overnight – at least 8 hours, or up to 24.
This step draws out the juices and softens the fruit so it cooks faster and tastes better.
Step 3: Freeze Metal Spoons
Put a few metal spoons in the freezer before you start cooking the jam. You’ll use them later to test if the jam is done.
Step 4: Cook the Plum Mixture
Pour the macerated plums and all their juice into a wide pot or Dutch oven. If you’re using Pomona’s Pectin, stir in the calcium water now. Turn the heat to medium and bring the mixture to a simmer.
Stir regularly and let it cook until the plums are soft – this usually takes about 15 minutes.
Step 5: Mill Half the Plums (Optional)
If you want a smoother jam, ladle about half of the cooked mixture into a food mill and process it into a bowl. Then pour the smooth part back into the pot with the rest of the fruit.
This gives the jam a nice balance between smooth and chunky.
Step 6: Reduce and Skim
Keep the jam simmering. As it cooks, it’ll start to foam and reduce. Stir often and scrape off the foam with a spoon if you want a clearer, glossier finish.
Cook it down until the volume drops by about a quarter.
Step 7: Add Butter and Lemon Juice
Stir in a teaspoon of unsalted butter to help with any remaining foam. If you're planning to can the jam, add the bottled lemon juice now.
Keep the jam cooking until it thickens and turns glossy – usually another 15 to 30 minutes.
Step 8: Test for Doneness
Take one of your frozen spoons and drop a little jam on it. Put it back in the freezer for 5 minutes.
Take it out and run your finger through the jam. If it’s thick and spreadable (not runny) it’s ready.
If not, cook a little longer and test again.
Step 9: Fill and Seal Jars
For refrigerator jam, just spoon the hot jam into clean jars. Put the lids on and let them cool to room temperature before refrigerating.
For canning, sterilize your jars and lids in boiling water. Fill the hot jars using a funnel, leaving about ¼ inch of space at the top.
Wipe the rims, place the lids on, and screw the rings on just until snug (not too tight).
Step 10: Process (Canning Only)
Put the filled jars in a boiling water bath. Make sure they’re fully covered with water.
Boil for 10 minutes, then carefully remove the jars and let them cool on the counter.
As they cool, the lids should seal with a small “ping.” Once they’ve cooled completely, check the seals. If sealed properly, the lids won’t flex when pressed.
Remove the rings and store the jars in a cool, dark place.
Storing Your Plum Jam
Once your jam is cooked and jarred, you’ve got two ways to store it – in the fridge for quick use or processed for shelf storage.
It just depends on how long you want it to last and whether you want to can it.
Refrigerator Storage
If you’re not canning the jam, let the filled jars cool at room temperature.
Once they’re cool, tighten the lids and put them in the fridge.
You don’t need to add lemon juice for this version, and it keeps the flavor more plum-forward.
The jam will last for a couple of months in the fridge.
Shelf-Stable Canning
If you want to store your jam for longer, you’ll need to can it:
- Sterilize the jars and lids in boiling water.
- Fill hot jars with hot jam, leaving about ¼ inch of space at the top.
- Wipe the rims clean and put the lids on. Screw the rings on until they’re snug (not cranked tight).
- Process the jars in a boiling water bath for 10 minutes, fully submerged.
- Let them cool on the counter, undisturbed. As they cool, the lids should seal with a light pop or ping.
- Once fully cool, check the seals by pressing the centers – sealed lids won’t flex.
- Remove the rings and store the jars in a cool, dark place.
Properly sealed jars can last up to a year on the shelf.
For more guidance on keeping your preserves safe and fresh, see our canned food storage tips.
Wrap Up Your Summer Harvest with Homemade Plum Jam
Making your own plum jam isn’t complicated – and it’s a good way to use up ripe fruit without letting it go to waste.
With just a few basic ingredients and a bit of time, you’ll end up with a jam that tastes like real fruit, not just sugar.
Whether you keep it chunky or smooth, store it in the fridge or preserve it for later, it’s flexible enough to suit what you have and how you like it.
Got questions, tips, or your own way of making plum jam? Comment down below – would love to hear how you do it.
Frequently Asked Questions
Can I use frozen plums to make this jam?
Yes, frozen plums work fine. Let them thaw completely before starting, and use the same weight as you would for fresh plums.
Do I need to peel the plums first?
No. The skins break down during cooking and add flavor, color, and texture to the jam.
Why does my jam have so much foam?
Foam is normal during cooking. Stirring in a small amount of butter helps reduce it. You can also skim it off before jarring if you want a clearer jam.
Can I skip the pectin?
Yes, but the jam will take longer to cook and may not set as firmly. If you're okay with a looser jam, there’s no need for pectin.
How do I know if my canned jars are sealed properly?
After cooling, press the center of each lid. If it doesn’t move, it’s sealed. If it pops up and down, it didn’t seal and should be refrigerated and used first.