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There’s something incredibly satisfying about preserving the taste of summer in a jar. If you’ve got a bounty of ripe plums, turning them into plum jam is one of the most delicious ways to enjoy them all year round. This guide walks you through everything you need to know about making and canning your own homemade plum jam, from selecting the right fruit to troubleshooting common jam-making issues.

Whether you’re a seasoned canner or trying this for the first time, learning the proper method for water bath canning ensures your jam stays shelf-stable and safe to eat. For the most reliable canning guidelines, you can refer to the National Center for Home Food Preservation, which provides USDA-tested instructions for jams and jellies.

Understanding how pectin works is key to getting that perfect jam set. If you’re curious about why your jam thickens (or doesn’t), Serious Eats offers a deep dive into pectin science to help you troubleshoot and adjust recipes confidently.

Ingredients for Homemade Plum Jam

To make a rich, flavorful plum jam, you’ll need just a few simple ingredients:

4 pounds of ripe plums (preferably Damson, Italian, or Santa Rosa)
3 cups granulated sugar (can adjust for low-sugar or sugar-free versions)
2 tablespoons fresh lemon juice
1/2 teaspoon ground cinnamon (optional)
1 packet of fruit pectin (optional, depending on the plum variety)

Tools and Equipment You’ll Need

Before you start, gather all your canning supplies:

Water bath canner or a large deep pot with a rack
6–8 half-pint canning jars with new lids and bands
Jar lifter, lid lifter, and canning funnel
Potato masher or immersion blender
Large non-reactive pot (stainless steel or enamel-coated)

How to Prepare Plums for Jam

Plums don’t need to be peeled for jam, but you do need to wash, pit, and chop them:

Wash thoroughly under cool water
Cut plums in half and remove pits
Chop roughly; the skins will break down during cooking
Optional: If you want a smoother jam, peel by blanching the plums briefly in boiling water and slipping off the skins

Cooking the Plum Jam

Now, let’s cook your fruit down into a jammy, aromatic preserve:

Combine chopped plums and lemon juice in a large pot
Simmer on medium heat until plums begin to soften
Use a masher or blender to reach desired consistency
Add sugar (and pectin, if using) and bring mixture to a rolling boil
Boil hard for 1–2 minutes while stirring constantly
Skim off any foam for a cleaner finish

To test for doneness, place a spoonful on a chilled plate. If it wrinkles when pushed, your jam is ready to jar.

Step-by-Step Water Bath Canning

Sterilizing and sealing your jars properly is essential to prevent spoilage. Here’s how to can plum jam safely:

Sterilize jars and lids by boiling or washing in the dishwasher
Fill hot jars with jam, leaving 1/4 inch headspace
Wipe rims clean and apply lids and bands finger-tight
Process in a boiling water bath for 10–15 minutes (adjust for altitude using this guide)
Remove and cool jars undisturbed for 12–24 hours

Listen for the satisfying “pop” of jars sealing as they cool!

How to Store and Use Your Plum Jam

Once sealed, your plum jam is shelf-stable for up to 1 year in a cool, dark place. After opening, refrigerate and use within 3 weeks.

Try serving your jam:

On toast or biscuits
As a glaze for pork or chicken
Paired with cheese boards
In thumbprint cookies or tarts

Recipe Variations to Try

Get creative with these tasty variations:

Spiced Plum Jam – Add ground cloves, cinnamon, and a splash of vanilla
Plum & Ginger Jam – Add grated fresh ginger during cooking
Low Sugar Jam – Use low-methoxyl pectin or reduce sugar by half
Plum-Apple Jam – Mix equal parts plum and tart apple for a twist

Tips for First-Time Canners

Making jam can feel intimidating, but these tips will help:

Always start with clean, sterilized jars
Use a wide pot to avoid boiling over
Don’t double the recipe — it affects the set
Label jars with date and contents for easy tracking

Common Jam Troubleshooting

If something seems off with your jam, here’s how to fix it:

Jam too runny: Reboil with added pectin or lemon juice
Too thick: You may have overcooked; try stirring in a little hot water
Cloudy appearance: Stirring too much or not skimming foam
Jar didn’t seal: Refrigerate and use within 3 weeks

FAQs About Plum Jam Canning

Do you need pectin for plum jam?
Not always. Plums are naturally high in pectin, especially when under-ripe.

Do you peel plums for jam?
No, the skins cook down nicely and add color. Peel only if you prefer a smoother texture.

How long does homemade plum jam last?
Properly canned, up to 12 months in the pantry; 3 weeks once opened and refrigerated.

Can you freeze plum jam instead of canning?
Yes, store in freezer-safe containers and leave space for expansion.

What’s the right fruit-to-sugar ratio?
A general rule is 2:1 fruit to sugar, but it varies with fruit sweetness and pectin content.

Nutrition and Storage Info

A tablespoon of homemade plum jam typically contains:

Around 40–50 calories
Minimal fat
Gluten-free and vegan (depending on added ingredients)

Store sealed jars in a cool, dark pantry. Refrigerate once opened.

Final Thoughts

Making your own plum jam is not only a rewarding project, but a practical way to enjoy fresh fruit all year. With a few simple tools and the right guidance, your pantry can be stocked with jewel-toned jars that make breakfast (and gifting!) extra special.